TY - JOUR A1 - Jiang, Jin-Wu A1 - Wang, Bing-Shen A1 - Rabczuk, Timon T1 - Why twisting angles are diverse in graphene Moir’e patterns? JF - Journal of Applied Physics N2 - Why twisting angles are diverse in graphene Moir’e patterns? KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Döring, R. A1 - Hoffmeyer, J. A1 - Seeger, T. A1 - Vormwald, Michael T1 - Verformungsverhalten und rechnerische Abschätzung der Ermüdungslebensdauer metallischer Werkstoffe unter mehrachsig nichtproportionaler Beanspruchung JF - Materialwissenschaft und Werkstofftechnik N2 - Verformungsverhalten und rechnerische Abschätzung der Ermüdungslebensdauer metallischer Werkstoffe unter mehrachsig nichtproportionaler Beanspruchung KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2002 SP - 280 EP - 288 ER - TY - JOUR A1 - Lahmer, Tom A1 - Ilg, J. A1 - Lerch, Reinhard T1 - Variance-based sensitivity analyses of piezoelectric models JF - Computer Modeling in Engineering & Sciences N2 - Variance-based sensitivity analyses of piezoelectric models KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2015 SP - 105 EP - 126 ER - TY - JOUR A1 - Faizollahzadeh Ardabili, Sina A1 - Najafi, Bahman A1 - Alizamir, Meysam A1 - Mosavi, Amir A1 - Shamshirband, Shahaboddin A1 - Rabczuk, Timon T1 - Using SVM-RSM and ELM-RSM Approaches for Optimizing the Production Process of Methyl and Ethyl Esters JF - Energies N2 - The production of a desired product needs an effective use of the experimental model. The present study proposes an extreme learning machine (ELM) and a support vector machine (SVM) integrated with the response surface methodology (RSM) to solve the complexity in optimization and prediction of the ethyl ester and methyl ester production process. The novel hybrid models of ELM-RSM and ELM-SVM are further used as a case study to estimate the yield of methyl and ethyl esters through a trans-esterification process from waste cooking oil (WCO) based on American Society for Testing and Materials (ASTM) standards. The results of the prediction phase were also compared with artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS), which were recently developed by the second author of this study. Based on the results, an ELM with a correlation coefficient of 0.9815 and 0.9863 for methyl and ethyl esters, respectively, had a high estimation capability compared with that for SVM, ANNs, and ANFIS. Accordingly, the maximum production yield was obtained in the case of using ELM-RSM of 96.86% for ethyl ester at a temperature of 68.48 °C, a catalyst value of 1.15 wt. %, mixing intensity of 650.07 rpm, and an alcohol to oil molar ratio (A/O) of 5.77; for methyl ester, the production yield was 98.46% at a temperature of 67.62 °C, a catalyst value of 1.1 wt. %, mixing intensity of 709.42 rpm, and an A/O of 6.09. Therefore, ELM-RSM increased the production yield by 3.6% for ethyl ester and 3.1% for methyl ester, compared with those for the experimental data. KW - Biodiesel KW - Optimierung KW - extreme learning machine KW - machine learning KW - response surface methodology KW - support vector machine KW - OA-Publikationsfonds2018 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20181025-38170 UR - https://www.mdpi.com/1996-1073/11/11/2889 IS - 11, 2889 SP - 1 EP - 20 PB - MDPI CY - Basel ER - TY - JOUR A1 - Ilyani Akmar, A.B. A1 - Lahmer, Tom A1 - Bordas, Stéphane Pierre Alain A1 - Beex, L.A.A. A1 - Rabczuk, Timon T1 - Uncertainty quantification of dry woven fabrics: A sensitivity analysis on material properties JF - Composite Structures N2 - Uncertainty quantification of dry woven fabrics: A sensitivity analysis on material properties KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.compstruct.2014.04.014 SP - 1 EP - 17 ER - TY - JOUR A1 - Vu-Bac, N. A1 - Rafiee, Roham A1 - Zhuang, Xiaoying A1 - Lahmer, Tom A1 - Rabczuk, Timon T1 - Uncertainty quantification for multiscale modeling of polymer nanocomposites with correlated parameters JF - Composites Part B: Engineering N2 - Uncertainty quantification for multiscale modeling of polymer nanocomposites with correlated parameters KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2015 SP - 446 EP - 464 ER - TY - JOUR A1 - Göbel, Luise A1 - Lahmer, Tom A1 - Osburg, Andrea T1 - Uncertainty analysis in multiscale modeling of concrete based on continuum micromechanics JF - European Journal of Mechanics-A/Solids N2 - Uncertainty analysis in multiscale modeling of concrete based on continuum micromechanics KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Rafiee, Roham A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Uncertainties propagation in metamodel-based probabilistic optimization of CNT/polymer composite structure using stochastic multi-scale modeling JF - Computational Materials Science N2 - Uncertainties propagation in metamodel-based probabilistic optimization of CNT/polymer composite structure using stochastic multi-scale modeling KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 295 EP - 305 ER - TY - JOUR A1 - Nanthakumar, S.S. A1 - Lahmer, Tom A1 - Zhuang, Xiaoying A1 - Park, Harold S. A1 - Rabczuk, Timon T1 - Topology optimization of piezoelectric nanostructures JF - Journal of the Mechanics and Physics of Solids N2 - Topology optimization of piezoelectric nanostructures KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 SP - 316 EP - 335 ER - TY - JOUR A1 - Alemu, Yohannes L. A1 - Habte, Bedilu A1 - Lahmer, Tom A1 - Urgessa, Girum T1 - Topologically preoptimized ground structure (TPOGS) for the optimization of 3D RC buildings JF - Asian Journal of Civil Engineering N2 - As an optimization that starts from a randomly selected structure generally does not guarantee reasonable optimality, the use of a systemic approach, named the ground structure, is widely accepted in steel-made truss and frame structural design. However, in the case of reinforced concrete (RC) structural optimization, because of the orthogonal orientation of structural members, randomly chosen or architect-sketched framing is used. Such a one-time fixed layout trend, in addition to its lack of a systemic approach, does not necessarily guarantee optimality. In this study, an approach for generating a candidate ground structure to be used for cost or weight minimization of 3D RC building structures with included slabs is developed. A multiobjective function at the floor optimization stage and a single objective function at the frame optimization stage are considered. A particle swarm optimization (PSO) method is employed for selecting the optimal ground structure. This method enables generating a simple, yet potential, real-world representation of topologically preoptimized ground structure while both structural and main architectural requirements are considered. This is supported by a case study for different floor domain sizes. KW - Bodenmechanik KW - Strukturanalyse KW - Optimierung KW - Stahlbetonkonstruktion KW - Dreidimensionales Modell KW - ground structure KW - TPOGS KW - topology optimization KW - 3D reinforced concrete buildings Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230517-63677 UR - https://link.springer.com/article/10.1007/s42107-023-00640-2 VL - 2023 SP - 1 EP - 11 PB - Springer International Publishing CY - Cham ER - TY - JOUR A1 - Lahmer, Tom A1 - Nguyen-Tuan, Long A1 - Könke, Carsten A1 - Bettzieche, Volker T1 - Thermo-hydro-mechanische 3-D-Simulation von Staumauern‐Modellierung und Validierung JF - WASSERWIRTSCHAFT N2 - Thermo-hydro-mechanische 3-D-Simulation von Staumauern‐Modellierung und Validierung KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 SP - 27 EP - 30 ER - TY - JOUR A1 - Zhang, Chao A1 - Hao, Xiao-Li A1 - Wang, Cuixia A1 - Wei, Ning A1 - Rabczuk, Timon T1 - Thermal conductivity of graphene nanoribbons under shear deformation: A molecular dynamics simulation JF - Scientific Reports N2 - Tensile strain and compress strain can greatly affect the thermal conductivity of graphene nanoribbons (GNRs). However, the effect of GNRs under shear strain, which is also one of the main strain effect, has not been studied systematically yet. In this work, we employ reverse nonequilibrium molecular dynamics (RNEMD) to the systematical study of the thermal conductivity of GNRs (with model size of 4 nm × 15 nm) under the shear strain. Our studies show that the thermal conductivity of GNRs is not sensitive to the shear strain, and the thermal conductivity decreases only 12–16% before the pristine structure is broken. Furthermore, the phonon frequency and the change of the micro-structure of GNRs, such as band angel and bond length, are analyzed to explore the tendency of thermal conductivity. The results show that the main influence of shear strain is on the in-plane phonon density of states (PDOS), whose G band (higher frequency peaks) moved to the low frequency, thus the thermal conductivity is decreased. The unique thermal properties of GNRs under shear strains suggest their great potentials for graphene nanodevices and great potentials in the thermal managements and thermoelectric applications. KW - Wärmeleitfähigkeit KW - Graphen KW - Schubspannung Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170428-31718 ER - TY - JOUR A1 - Zhao, Jiyun A1 - Lu, Lixin A1 - Rabczuk, Timon T1 - The tensile and shear failure behavior dependence on chain length and temperature in amorphous polymers JF - Computational Materials Science N2 - The tensile and shear failure behavior dependence on chain length and temperature in amorphous polymers KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 567 EP - 572 ER - TY - JOUR A1 - Fathi, Sadegh A1 - Sajadzadeh, Hassan A1 - Mohammadi Sheshkal, Faezeh A1 - Aram, Farshid A1 - Pinter, Gergo A1 - Felde, Imre A1 - Mosavi, Amir T1 - The Role of Urban Morphology Design on Enhancing Physical Activity and Public Health JF - International Journal of Environmental Research and Public Health N2 - Along with environmental pollution, urban planning has been connected to public health. The research indicates that the quality of built environments plays an important role in reducing mental disorders and overall health. The structure and shape of the city are considered as one of the factors influencing happiness and health in urban communities and the type of the daily activities of citizens. The aim of this study was to promote physical activity in the main structure of the city via urban design in a way that the main form and morphology of the city can encourage citizens to move around and have physical activity within the city. Functional, physical, cultural-social, and perceptual-visual features are regarded as the most important and effective criteria in increasing physical activities in urban spaces, based on literature review. The environmental quality of urban spaces and their role in the physical activities of citizens in urban spaces were assessed by using the questionnaire tool and analytical network process (ANP) of structural equation modeling. Further, the space syntax method was utilized to evaluate the role of the spatial integration of urban spaces on improving physical activities. Based on the results, consideration of functional diversity, spatial flexibility and integration, security, and the aesthetic and visual quality of urban spaces plays an important role in improving the physical health of citizens in urban spaces. Further, more physical activities, including motivation for walking and the sense of public health and happiness, were observed in the streets having higher linkage and space syntax indexes with their surrounding texture. KW - Morphologie KW - Gesundheitswesen KW - Intelligente Stadt KW - Nachhaltigkeit KW - Gesundheitsinformationssystem KW - urban morphology KW - public health KW - physical activities KW - health KW - public space KW - urban health KW - smart cities KW - sustainability Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200402-41225 UR - https://www.mdpi.com/1660-4601/17/7/2359 VL - 2020 IS - Volume 17, Issue 7, 2359 PB - MDPI CY - Basel ER - TY - JOUR A1 - Ben, S. A1 - Zhao, Jun-Hua A1 - Zhang, Yancheng A1 - Rabczuk, Timon T1 - The interface strength and debonding for composite structures: review and recent developments JF - Composite Structures N2 - The interface strength and debonding for composite structures: review and recent developments KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 ER - TY - JOUR A1 - Areias, Pedro A1 - Rabczuk, Timon A1 - Barbosa, J.I. T1 - The extended unsymmetric frontal solution for multiple-point constraints JF - Engineering Computations N2 - The extended unsymmetric frontal solution for multiple-point constraints KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Işık, Ercan A1 - Büyüksaraç, Aydın A1 - Levent Ekinci, Yunus A1 - Aydın, Mehmet Cihan A1 - Harirchian, Ehsan T1 - The Effect of Site-Specific Design Spectrum on Earthquake-Building Parameters: A Case Study from the Marmara Region (NW Turkey) JF - Applied Sciences N2 - The Marmara Region (NW Turkey) has experienced significant earthquakes (M > 7.0) to date. A destructive earthquake is also expected in the region. To determine the effect of the specific design spectrum, eleven provinces located in the region were chosen according to the Turkey Earthquake Building Code updated in 2019. Additionally, the differences between the previous and updated regulations of the country were investigated. Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) were obtained for each province by using earthquake ground motion levels with 2%, 10%, 50%, and 68% probability of exceedance in 50-year periods. The PGA values in the region range from 0.16 to 0.7 g for earthquakes with a return period of 475 years. For each province, a sample of a reinforced-concrete building having two different numbers of stories with the same ground and structural characteristics was chosen. Static adaptive pushover analyses were performed for the sample reinforced-concrete building using each province’s design spectrum. The variations in the earthquake and structural parameters were investigated according to different geographical locations. It was determined that the site-specific design spectrum significantly influences target displacements for performance-based assessments of buildings due to seismicity characteristics of the studied geographic location. KW - Erdbeben KW - earthquake KW - site-specific spectrum KW - Marmara Region KW - seismic hazard analysis KW - adaptive pushover KW - OA-Publikationsfonds2020 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20201022-42758 UR - https://www.mdpi.com/2076-3417/10/20/7247 VL - 2020 IS - Volume 10, issue 20, article 7247 PB - MDPI CY - Basel ER - TY - JOUR A1 - Zerbst, U. A1 - Vormwald, Michael A1 - Andersch, C. A1 - Mädler, K. A1 - Pfuff, M. T1 - The development of a damage tolerance concept for railway components and its demonstration for a railway axle JF - Engineering Fracture Mechanics N2 - The development of a damage tolerance concept for railway components and its demonstration for a railway axle KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2005 SP - 209 EP - 239 ER - TY - JOUR A1 - Zhao, Jun-Hua A1 - Kou, Liangzhi A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures JF - Nanotechnology N2 - Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 U6 - http://dx.doi.org/10.1088/0957-4484/25/29/295701 ER - TY - JOUR A1 - Ghorashi, Seyed Shahram A1 - Valizadeh, Navid A1 - Mohammadi, S. A1 - Rabczuk, Timon T1 - T-spline based XIGA for Fracture Analysis of Orthotropic Media JF - Computers & Structures N2 - T-spline based XIGA for Fracture Analysis of Orthotropic Media KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 138 EP - 146 ER - TY - JOUR A1 - Unger, Jörg F. A1 - Teughels, A. A1 - De Roeck, G. T1 - System identification and damage detection of a prestressed concrete beam JF - Journal of Structural Engineering N2 - System identification and damage detection of a prestressed concrete beam KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 1691 EP - 1698 ER - TY - JOUR A1 - Stein, Peter A1 - Lahmer, Tom A1 - Bock, Sebastian T1 - Synthese und Analyse von gekoppelten Modellen im konstruktiven Ingenieurbau BT - Sonderdruck‐DFG Graduiertenkolleg JF - Bautechnik N2 - Synthese und Analyse von gekoppelten Modellen im konstruktiven Ingenieurbau KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2011 SP - 8 EP - 11 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Zhao, Jun-Hua A1 - Zhou, K. A1 - Rabczuk, Timon T1 - Superior thermal conductivity and extremely high mechanical strength in polyethylene chains from ab initio calculation JF - Journal of Applied Physics N2 - The upper limit of the thermal conductivity and the mechanical strength are predicted for the polyethylene chain, by performing the ab initio calculation and applying the quantum mechanical non-equilibrium Green’s function approach. Specially, there are two main findings from our calculation: (1) the thermal conductivity can reach a high value of 310 Wm−1 K−1 in a 100 nm polyethylene chain at room temperature and the thermal conductivity increases with the length of the chain; (2) the Young’s modulus in the polyethylene chain is as high as 374.5 GPa, and the polyethylene chain can sustain 32.85%±0.05% (ultimate) strain before undergoing structural phase transition into gaseous ethylene. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1063/1.4729489 ER - TY - JOUR A1 - Ghazvinei, Pezhman Taherei A1 - Darvishi, Hossein Hassanpour A1 - Mosavi, Amir A1 - Yusof, Khamaruzaman bin Wan A1 - Alizamir, Meysam A1 - Shamshirband, Shahaboddin A1 - Chau, Kwok-Wing T1 - Sugarcane growth prediction based on meteorological parameters using extreme learning machine and artificial neural network JF - Engineering Applications of Computational Fluid Mechanics N2 - Management strategies for sustainable sugarcane production need to deal with the increasing complexity and variability of the whole sugar system. Moreover, they need to accommodate the multiple goals of different industry sectors and the wider community. Traditional disciplinary approaches are unable to provide integrated management solutions, and an approach based on whole systems analysis is essential to bring about beneficial change to industry and the community. The application of this approach to water management, environmental management and cane supply management is outlined, where the literature indicates that the application of extreme learning machine (ELM) has never been explored in this realm. Consequently, the leading objective of the current research was set to filling this gap by applying ELM to launch swift and accurate model for crop production data-driven. The key learning has been the need for innovation both in the technical aspects of system function underpinned by modelling of sugarcane growth. Therefore, the current study is an attempt to establish an integrate model using ELM to predict the concluding growth amount of sugarcane. Prediction results were evaluated and further compared with artificial neural network (ANN) and genetic programming models. Accuracy of the ELM model is calculated using the statistics indicators of Root Means Square Error (RMSE), Pearson Coefficient (r), and Coefficient of Determination (R2) with promising results of 0.8, 0.47, and 0.89, respectively. The results also show better generalization ability in addition to faster learning curve. Thus, proficiency of the ELM for supplementary work on advancement of prediction model for sugarcane growth was approved with promising results. KW - Künstliche Intelligenz KW - Sustainable production KW - ELM KW - prediction KW - machine learning KW - sugarcane KW - estimation KW - growth mode KW - extreme learning machine KW - OA-Publikationsfonds2018 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20181017-38129 UR - https://www.tandfonline.com/doi/full/10.1080/19942060.2018.1526119 VL - 2018 IS - 12,1 SP - 738 EP - 749 PB - Taylor & Francis ER - TY - JOUR A1 - Most, Thomas A1 - Bucher, Christian T1 - Stochastic simulation of cracking in concrete structures using multi-parameter random fields JF - International Journal of Reliability and Safety N2 - Stochastic simulation of cracking in concrete structures using multi-parameter random fields KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 168 EP - 187 ER - TY - JOUR A1 - Vu-Bac, N. A1 - Lahmer, Tom A1 - Zhang, Yancheng A1 - Zhuang, Xiaoying A1 - Rabczuk, Timon T1 - Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs) JF - Composites Part B Engineering N2 - Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs) KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2014 SP - 80 EP - 95 ER - TY - JOUR A1 - Vu-Bac, N. A1 - Lahmer, Tom A1 - Keitel, Holger A1 - Zhao, Jun-Hua A1 - Zhuang, Xiaoying A1 - Rabczuk, Timon T1 - Stochastic predictions of bulk properties of amorphous polyethylene based on molecular dynamics simulations JF - Mechanics of Materials N2 - Stochastic predictions of bulk properties of amorphous polyethylene based on molecular dynamics simulations KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2014 SP - 70 EP - 84 ER - TY - JOUR A1 - Rabczuk, Timon A1 - Guo, Hongwei A1 - Zhuang, Xiaoying A1 - Chen, Pengwan A1 - Alajlan, Naif T1 - Stochastic deep collocation method based on neural architecture search and transfer learning for heterogeneous porous media JF - Engineering with Computers N2 - We present a stochastic deep collocation method (DCM) based on neural architecture search (NAS) and transfer learning for heterogeneous porous media. We first carry out a sensitivity analysis to determine the key hyper-parameters of the network to reduce the search space and subsequently employ hyper-parameter optimization to finally obtain the parameter values. The presented NAS based DCM also saves the weights and biases of the most favorable architectures, which is then used in the fine-tuning process. We also employ transfer learning techniques to drastically reduce the computational cost. The presented DCM is then applied to the stochastic analysis of heterogeneous porous material. Therefore, a three dimensional stochastic flow model is built providing a benchmark to the simulation of groundwater flow in highly heterogeneous aquifers. The performance of the presented NAS based DCM is verified in different dimensions using the method of manufactured solutions. We show that it significantly outperforms finite difference methods in both accuracy and computational cost. KW - Maschinelles Lernen KW - Neuronales Lernen KW - Fehlerabschätzung KW - deep learning KW - neural architecture search KW - randomized spectral representation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45835 UR - https://link.springer.com/article/10.1007/s00366-021-01586-2 VL - 2022 SP - 1 EP - 26 PB - Springer CY - London ER - TY - JOUR A1 - Kerfriden, Pierre A1 - Schmidt, K.M. A1 - Rabczuk, Timon A1 - Bordas, Stéphane Pierre Alain T1 - Statistical extraction of process zones and representative subspaces in fracture of random composites JF - International Journal for Multiscale Computational Engineering N2 - Statistical extraction of process zones and representative subspaces in fracture of random composites KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Thai, Chien H. A1 - Nguyen-Xuan, Hung A1 - Nguyen-Thanh, Nhon A1 - Le, T.H. A1 - Nguyen-Thoi, T. A1 - Rabczuk, Timon T1 - Static, free vibration and buckling analysis of laminated composite Reissner-Mindlin plates using NURBS-based isogeometric approach JF - International Journal for Numerical Methods in Engineering N2 - This paper presents a novel numerical procedure based on the framework of isogeometric analysis for static, free vibration, and buckling analysis of laminated composite plates using the first-order shear deformation theory. The isogeometric approach utilizes non-uniform rational B-splines to implement for the quadratic, cubic, and quartic elements. Shear locking problem still exists in the stiffness formulation, and hence, it can be significantly alleviated by a stabilization technique. Several numerical examples are presented to show the performance of the method, and the results obtained are compared with other available ones. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1002/nme.4282 SP - 571 EP - 603 ER - TY - JOUR A1 - Dehghani, Majid A1 - Salehi, Somayeh A1 - Mosavi, Amir A1 - Nabipour, Narjes A1 - Shamshirband, Shahaboddin A1 - Ghamisi, Pedram T1 - Spatial Analysis of Seasonal Precipitation over Iran: Co-Variation with Climate Indices JF - ISPRS, International Journal of Geo-Information N2 - Temporary changes in precipitation may lead to sustained and severe drought or massive floods in different parts of the world. Knowing the variation in precipitation can effectively help the water resources decision-makers in water resources management. Large-scale circulation drivers have a considerable impact on precipitation in different parts of the world. In this research, the impact of El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO) on seasonal precipitation over Iran was investigated. For this purpose, 103 synoptic stations with at least 30 years of data were utilized. The Spearman correlation coefficient between the indices in the previous 12 months with seasonal precipitation was calculated, and the meaningful correlations were extracted. Then, the month in which each of these indices has the highest correlation with seasonal precipitation was determined. Finally, the overall amount of increase or decrease in seasonal precipitation due to each of these indices was calculated. Results indicate the Southern Oscillation Index (SOI), NAO, and PDO have the most impact on seasonal precipitation, respectively. Additionally, these indices have the highest impact on the precipitation in winter, autumn, spring, and summer, respectively. SOI has a diverse impact on winter precipitation compared to the PDO and NAO, while in the other seasons, each index has its special impact on seasonal precipitation. Generally, all indices in different phases may decrease the seasonal precipitation up to 100%. However, the seasonal precipitation may increase more than 100% in different seasons due to the impact of these indices. The results of this study can be used effectively in water resources management and especially in dam operation. KW - Maschinelles Lernen KW - Machine learning KW - spatiotemporal database KW - spatial analysis KW - seasonal precipitation KW - spearman correlation coefficient Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200128-40740 UR - https://www.mdpi.com/2220-9964/9/2/73 VL - 2020 IS - Volume 9, Issue 2, 73 PB - MDPI ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Zhao, Jun-Hua A1 - Rabczuk, Timon T1 - Size-Sensitive Young’s Modulus of Kinked Silicon Nanowires JF - Nanotechnology N2 - We perform both classical molecular dynamics simulations and beam model calculations to investigate the Young's modulus of kinked silicon nanowires (KSiNWs). The Young's modulus is found to be highly sensitive to the arm length of the kink and is essentially inversely proportional to the arm length. The mechanism underlying the size dependence is found to be the interplay between the kink angle potential and the arm length potential, where we obtain an analytic relationship between the Young's modulus and the arm length of the KSiNW. Our results provide insight into the application of this novel building block in nanomechanical devices. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 U6 - http://dx.doi.org/10.1088/0957-4484/24/18/185702 ER - TY - JOUR A1 - Natarajan, S. A1 - Chakraborty, S. A1 - Thangavel, M. A1 - Bordas, Stéphane Pierre Alain A1 - Rabczuk, Timon T1 - Size dependent free flexural vibration behavior of functionally graded nanoplates JF - Computational Materials Science N2 - Size dependent free flexural vibration behavior of functionally graded nanoplates KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 SP - 74 EP - 80 ER - TY - JOUR A1 - Nabipour, Narjes A1 - Dehghani, Majid A1 - Mosavi, Amir A1 - Shamshirband, Shahaboddin T1 - Short-Term Hydrological Drought Forecasting Based on Different Nature-Inspired Optimization Algorithms Hybridized With Artificial Neural Networks JF - IEEE Access N2 - Hydrological drought forecasting plays a substantial role in water resources management. Hydrological drought highly affects the water allocation and hydropower generation. In this research, short term hydrological drought forecasted based on the hybridized of novel nature-inspired optimization algorithms and Artificial Neural Networks (ANN). For this purpose, the Standardized Hydrological Drought Index (SHDI) and the Standardized Precipitation Index (SPI) were calculated in one, three, and six aggregated months. Then, three states where proposed for SHDI forecasting, and 36 input-output combinations were extracted based on the cross-correlation analysis. In the next step, newly proposed optimization algorithms, including Grasshopper Optimization Algorithm (GOA), Salp Swarm algorithm (SSA), Biogeography-based optimization (BBO), and Particle Swarm Optimization (PSO) hybridized with the ANN were utilized for SHDI forecasting and the results compared to the conventional ANN. Results indicated that the hybridized model outperformed compared to the conventional ANN. PSO performed better than the other optimization algorithms. The best models forecasted SHDI1 with R2 = 0.68 and RMSE = 0.58, SHDI3 with R 2 = 0.81 and RMSE = 0.45 and SHDI6 with R 2 = 0.82 and RMSE = 0.40. KW - Maschinelles Lernen KW - Machine learning KW - Deep learning KW - Hydrological drought KW - precipitation KW - hydrology Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200213-40796 UR - https://ieeexplore.ieee.org/document/8951168 VL - 2020 IS - volume 8 SP - 15210 EP - 15222 PB - IEEE ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Brighenti, Roberto A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Sequential reliability based optimization of fiber content and dispersion in fiber reinforced composite by using NURBS finite elements JF - Structural and Multidisciplinary Optimization N2 - Sequential reliability based optimization of fiber content and dispersion in fiber reinforced composite by using NURBS finite elements KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Nasser, Mourad A1 - Schwedler, Michael A1 - Wuttke, Frank A1 - Könke, Carsten T1 - Seismic analysis of structural response using simplified soil-structure interaction models JF - Bauingenieur, D-A-CH-Mitteilungsblatt N2 - Seismic analysis of structural response using simplified soil-structure interaction models KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2010 ER - TY - JOUR A1 - Nguyen-Thanh, Nhon A1 - Kiendl, J. A1 - Nguyen-Xuan, Hung A1 - Wüchner, R. A1 - Bletzinger, Kai-Uwe A1 - Bazilevs, Yuri A1 - Rabczuk, Timon T1 - Rotation free isogeometric thin shell analysis using PHT-splines JF - Computer Methods in Applied Mechanics and Engineering N2 - Rotation free isogeometric thin shell analysis using PHT-splines KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2011 SP - 3410 EP - 3424 ER - TY - JOUR A1 - Ouaer, Hocine A1 - Hosseini, Amir Hossein A1 - Amar, Menad Nait A1 - Ben Seghier, Mohamed El Amine A1 - Ghriga, Mohammed Abdelfetah A1 - Nabipour, Narjes A1 - Andersen, Pål Østebø A1 - Mosavi, Amir A1 - Shamshirband, Shahaboddin T1 - Rigorous Connectionist Models to Predict Carbon Dioxide Solubility in Various Ionic Liquids JF - Applied Sciences N2 - Estimating the solubility of carbon dioxide in ionic liquids, using reliable models, is of paramount importance from both environmental and economic points of view. In this regard, the current research aims at evaluating the performance of two data-driven techniques, namely multilayer perceptron (MLP) and gene expression programming (GEP), for predicting the solubility of carbon dioxide (CO2) in ionic liquids (ILs) as the function of pressure, temperature, and four thermodynamical parameters of the ionic liquid. To develop the above techniques, 744 experimental data points derived from the literature including 13 ILs were used (80% of the points for training and 20% for validation). Two backpropagation-based methods, namely Levenberg–Marquardt (LM) and Bayesian Regularization (BR), were applied to optimize the MLP algorithm. Various statistical and graphical assessments were applied to check the credibility of the developed techniques. The results were then compared with those calculated using Peng–Robinson (PR) or Soave–Redlich–Kwong (SRK) equations of state (EoS). The highest coefficient of determination (R2 = 0.9965) and the lowest root mean square error (RMSE = 0.0116) were recorded for the MLP-LMA model on the full dataset (with a negligible difference to the MLP-BR model). The comparison of results from this model with the vastly applied thermodynamic equation of state models revealed slightly better performance, but the EoS approaches also performed well with R2 from 0.984 up to 0.996. Lastly, the newly established correlation based on the GEP model exhibited very satisfactory results with overall values of R2 = 0.9896 and RMSE = 0.0201. KW - Maschinelles Lernen KW - Machine learning KW - OA-Publikationsfonds2020 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200107-40558 UR - https://www.mdpi.com/2076-3417/10/1/304 VL - 2020 IS - Volume 10, Issue 1, 304 PB - MDPI ER - TY - JOUR A1 - Thumser, Rayk A1 - Bergmann, Joachim W. A1 - Vormwald, Michael T1 - Residual stress fields and fatigue analysis of autofrettaged parts JF - International Journal of Pressure Vessels and Piping N2 - Residual stress fields and fatigue analysis of autofrettaged parts KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2002 SP - 113 EP - 117 ER - TY - JOUR A1 - Beex, L.A.A. A1 - Kerfriden, Pierre A1 - Rabczuk, Timon A1 - Bordas, Stéphane Pierre Alain T1 - Quasicontinuum-based multiscale approaches for plate-like beam lattices experiencing in-plane and out-of-plane deformation JF - Computer Methods in Applied Mechanics and Engineering N2 - Quasicontinuum-based multiscale approaches for plate-like beam lattices experiencing in-plane and out-of-plane deformation KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Zhang, Yancheng A1 - Wei, Ning A1 - Zhao, Jun-Hua A1 - Gong, Yadong A1 - Rabczuk, Timon T1 - Quasi-analytical solution for the stable system of the multi-layer folded graphene wrinkles JF - Journal of Applied Physics N2 - Quasi-analytical solution for the stable system of the multi-layer folded graphene wrinkles KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Most, Thomas A1 - Bucher, Christian T1 - Probabilistic analysis of concrete cracking using neural networks and random fields JF - Probabilistic Engineering Mechanics N2 - Probabilistic analysis of concrete cracking using neural networks and random fields KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2007 SP - 219 EP - 229 ER - TY - JOUR A1 - Mousavi, Seyed Nasrollah A1 - Steinke Júnior, Renato A1 - Teixeira, Eder Daniel A1 - Bocchiola, Daniele A1 - Nabipour, Narjes A1 - Mosavi, Amir A1 - Shamshirband, Shahaboddin T1 - Predictive Modeling the Free Hydraulic Jumps Pressure through Advanced Statistical Methods JF - Mathematics N2 - Pressure fluctuations beneath hydraulic jumps potentially endanger the stability of stilling basins. This paper deals with the mathematical modeling of the results of laboratory-scale experiments to estimate the extreme pressures. Experiments were carried out on a smooth stilling basin underneath free hydraulic jumps downstream of an Ogee spillway. From the probability distribution of measured instantaneous pressures, pressures with different probabilities could be determined. It was verified that maximum pressure fluctuations, and the negative pressures, are located at the positions near the spillway toe. Also, minimum pressure fluctuations are located at the downstream of hydraulic jumps. It was possible to assess the cumulative curves of pressure data related to the characteristic points along the basin, and different Froude numbers. To benchmark the results, the dimensionless forms of statistical parameters include mean pressures (P*m), the standard deviations of pressure fluctuations (σ*X), pressures with different non-exceedance probabilities (P*k%), and the statistical coefficient of the probability distribution (Nk%) were assessed. It was found that an existing method can be used to interpret the present data, and pressure distribution in similar conditions, by using a new second-order fractional relationships for σ*X, and Nk%. The values of the Nk% coefficient indicated a single mean value for each probability. KW - Maschinelles Lernen KW - Machine learning KW - mathematical modeling KW - extreme pressure KW - hydraulic jump KW - stilling basin KW - standard deviation of pressure fluctuations KW - statistical coeffcient of the probability distribution Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200402-41140 UR - https://www.mdpi.com/2227-7390/8/3/323 VL - 2020 IS - Volume 8, Issue 3, 323 PB - MDPI CY - Basel ER - TY - JOUR A1 - Sadeghzadeh, Milad A1 - Maddah, Heydar A1 - Ahmadi, Mohammad Hossein A1 - Khadang, Amirhosein A1 - Ghazvini, Mahyar A1 - Mosavi, Amir Hosein A1 - Nabipour, Narjes T1 - Prediction of Thermo-Physical Properties of TiO2-Al2O3/Water Nanoparticles by Using Artificial Neural Network JF - Nanomaterials N2 - In this paper, an artificial neural network is implemented for the sake of predicting the thermal conductivity ratio of TiO2-Al2O3/water nanofluid. TiO2-Al2O3/water in the role of an innovative type of nanofluid was synthesized by the sol–gel method. The results indicated that 1.5 vol.% of nanofluids enhanced the thermal conductivity by up to 25%. It was shown that the heat transfer coefficient was linearly augmented with increasing nanoparticle concentration, but its variation with temperature was nonlinear. It should be noted that the increase in concentration may cause the particles to agglomerate, and then the thermal conductivity is reduced. The increase in temperature also increases the thermal conductivity, due to an increase in the Brownian motion and collision of particles. In this research, for the sake of predicting the thermal conductivity of TiO2-Al2O3/water nanofluid based on volumetric concentration and temperature functions, an artificial neural network is implemented. In this way, for predicting thermal conductivity, SOM (self-organizing map) and BP-LM (Back Propagation-Levenberq-Marquardt) algorithms were used. Based on the results obtained, these algorithms can be considered as an exceptional tool for predicting thermal conductivity. Additionally, the correlation coefficient values were equal to 0.938 and 0.98 when implementing the SOM and BP-LM algorithms, respectively, which is highly acceptable. View Full-Text KW - Wärmeleitfähigkeit KW - Fluid KW - Neuronales Netz KW - Thermal conductivity KW - Nanofluid KW - Artificial neural network Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200421-41308 UR - https://www.mdpi.com/2079-4991/10/4/697 VL - 2020 IS - Volume 10, Issue 4, 697 PB - MDPI CY - Basel ER - TY - JOUR A1 - Shamshirband, Shahaboddin A1 - Babanezhad, Meisam A1 - Mosavi, Amir A1 - Nabipour, Narjes A1 - Hajnal, Eva A1 - Nadai, Laszlo A1 - Chau, Kwok-Wing T1 - Prediction of flow characteristics in the bubble column reactor by the artificial pheromone-based communication of biological ants JF - Engineering Applications of Computational Fluid Mechanics N2 - A novel combination of the ant colony optimization algorithm (ACO)and computational fluid dynamics (CFD) data is proposed for modeling the multiphase chemical reactors. The proposed intelligent model presents a probabilistic computational strategy for predicting various levels of three-dimensional bubble column reactor (BCR) flow. The results prove an enhanced communication between ant colony prediction and CFD data in different sections of the BCR. KW - Maschinelles Lernen KW - Machine learning KW - Bubble column reactor KW - ant colony optimization algorithm (ACO) KW - flow pattern KW - computational fluid dynamics (CFD) KW - big data KW - OA-Publikationsfonds2020 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200227-41013 UR - https://www.tandfonline.com/doi/full/10.1080/19942060.2020.1715842 VL - 2020 IS - volume 14, issue 1 SP - 367 EP - 378 PB - Taylor & Francis ER - TY - JOUR A1 - Hamdia, Khader A1 - Lahmer, Tom A1 - Nguyen-Thoi, T. A1 - Rabczuk, Timon T1 - Predicting The Fracture Toughness of PNCs: A Stochastic Approach Based on ANN and ANFIS JF - Computational Materials Science N2 - Predicting The Fracture Toughness of PNCs: A Stochastic Approach Based on ANN and ANFIS KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2015 SP - 304 EP - 313 ER - TY - JOUR A1 - Luther, Torsten A1 - Könke, Carsten T1 - Polycrystal models for the analysis of intergranular crack growth in metallic materials JF - Engineering Fracture Mechanics N2 - Polycrystal models for the analysis of intergranular crack growth in metallic materials KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2009 SP - 2332 EP - 2343 ER - TY - JOUR A1 - Banihani, Suleiman A1 - Rabczuk, Timon A1 - Almomani, Thakir T1 - POD for real-time simulation of hyperelastic soft biological tissue using the point collocation method of finite spheres JF - Mathematical Problems in Engineering N2 - The point collocation method of finite spheres (PCMFS) is used to model the hyperelastic response of soft biological tissue in real time within the framework of virtual surgery simulation. The proper orthogonal decomposition (POD) model order reduction (MOR) technique was used to achieve reduced-order model of the problem, minimizing computational cost. The PCMFS is a physics-based meshfree numerical technique for real-time simulation of surgical procedures where the approximation functions are applied directly on the strong form of the boundary value problem without the need for integration, increasing computational efficiency. Since computational speed has a significant role in simulation of surgical procedures, the proposed technique was able to model realistic nonlinear behavior of organs in real time. Numerical results are shown to demonstrate the effectiveness of the new methodology through a comparison between full and reduced analyses for several nonlinear problems. It is shown that the proposed technique was able to achieve good agreement with the full model; moreover, the computational and data storage costs were significantly reduced. KW - Chirurgie KW - Finite-Elemente-Methode Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170413-31203 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Wang, Bing-Shen A1 - Rabczuk, Timon T1 - Phonon modes in single-walled molybdenum disulphide nanotubes: lattice dynamics calculation and molecular dynamics simulation JF - Nanotechnology N2 - Phonon modes in single-walled molybdenum disulphide nanotubes: lattice dynamics calculation and molecular dynamics simulation KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Amiri, Fatemeh A1 - Millán, D. A1 - Shen, Y. A1 - Rabczuk, Timon A1 - Arroyo, M. T1 - Phase-field modeling of fracture in linear thin shells JF - Theoretical and Applied Fracture Mechanics N2 - Phase-field modeling of fracture in linear thin shells KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 102 EP - 109 ER - TY - JOUR A1 - Jamshidian, M. A1 - Rabczuk, Timon T1 - Phase field modelling of stressed grain growth: Analytical study and the effect of microstructural length scale JF - Journal of Computational Physics N2 - Phase field modelling of stressed grain growth: Analytical study and the effect of microstructural length scale KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 23 EP - 35 ER - TY - JOUR A1 - Chau-Dinh, T. A1 - Zi, Goangseup A1 - Lee, P.S. A1 - Song, Jeong-Hoon A1 - Rabczuk, Timon T1 - Phantom-node method for shell models with arbitrary cracks JF - Computers & Structures N2 - A phantom-node method is developed for three-node shell elements to describe cracks. This method can treat arbitrary cracks independently of the mesh. The crack may cut elements completely or partially. Elements are overlapped on the position of the crack, and they are partially integrated to implement the discontinuous displacement across the crack. To consider the element containing a crack tip, a new kinematical relation between the overlapped elements is developed. There is no enrichment function for the discontinuous displacement field. Several numerical examples are presented to illustrate the proposed method. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.compstruc.2011.10.021 ER - TY - JOUR A1 - Kaltenbacher, Barbara A1 - Lahmer, Tom A1 - Mohr, Marcus A1 - Kaltenbacher, Manfred T1 - PDE based determination of piezoelectric material tensors JF - European Journal of Applied Mathematics N2 - PDE based determination of piezoelectric material tensors. KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2006 U6 - http://dx.doi.org/10.25643/bauhaus-universitaet.3595 SP - 383 EP - 416 ER - TY - JOUR A1 - Shirazi, A. H. N. A1 - Mohebbi, Farzad A1 - Azadi Kakavand, M. R. A1 - He, B. A1 - Rabczuk, Timon T1 - Paraffin Nanocomposites for Heat Management of Lithium-Ion Batteries: A Computational Investigation JF - JOURNAL OF NANOMATERIALS N2 - Lithium-ion (Li-ion) batteries are currently considered as vital components for advances in mobile technologies such as those in communications and transport. Nonetheless, Li-ion batteries suffer from temperature rises which sometimes lead to operational damages or may even cause fire. An appropriate solution to control the temperature changes during the operation of Li-ion batteries is to embed batteries inside a paraffin matrix to absorb and dissipate heat. In the present work, we aimed to investigate the possibility of making paraffin nanocomposites for better heat management of a Li-ion battery pack. To fulfill this aim, heat generation during a battery charging/discharging cycles was simulated using Newman’s well established electrochemical pseudo-2D model. We couple this model to a 3D heat transfer model to predict the temperature evolution during the battery operation. In the later model, we considered different paraffin nanocomposites structures made by the addition of graphene, carbon nanotubes, and fullerene by assuming the same thermal conductivity for all fillers. This way, our results mainly correlate with the geometry of the fillers. Our results assess the degree of enhancement in heat dissipation of Li-ion batteries through the use of paraffin nanocomposites. Our results may be used as a guide for experimental set-ups to improve the heat management of Li-ion batteries. KW - Batterie KW - Wärmeleitfähigkeit Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170411-31141 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Zhuang, Xiaoying A1 - Rabczuk, Timon T1 - Orientation dependent thermal conductance in single-layer MoS 2 JF - Scientific Reports N2 - We investigate the thermal conductivity in the armchair and zigzag MoS2 nanoribbons, by combining the non-equilibrium Green's function approach and the first-principles method. A strong orientation dependence is observed in the thermal conductivity. Particularly, the thermal conductivity for the armchair MoS2 nanoribbon is about 673.6 Wm−1 K−1 in the armchair nanoribbon, and 841.1 Wm−1 K−1 in the zigzag nanoribbon at room temperature. By calculating the Caroli transmission, we disclose the underlying mechanism for this strong orientation dependence to be the fewer phonon transport channels in the armchair MoS2 nanoribbon in the frequency range of [150, 200] cm−1. Through the scaling of the phonon dispersion, we further illustrate that the thermal conductivity calculated for the MoS2 nanoribbon is esentially in consistent with the superior thermal conductivity found for graphene. KW - Mechanische Eigenschaft KW - Wärmeleitfähigkeit KW - Nanoribbons, thermal conductivity Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170418-31417 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Brighenti, Roberto A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Optimum fiber content and distribution in fiber-reinforced solids using a reliability and NURBS based sequential optimization approach JF - Structural and Multidisciplinary Optimization N2 - Optimum _ber content and distribution in _ber-reinforced solids using a reliability and NURBS based sequential optimization approach KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 99 EP - 112 ER - TY - JOUR A1 - Macke, M. A1 - Higuchi, Shoko T1 - Optimizing maintenance interventions for deteriorating structures using cost-benefit criteria JF - Journal of Structural Engineering N2 - Optimizing maintenance interventions for deteriorating structures using cost-benefit criteria KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2007 SP - 925 EP - 934 ER - TY - JOUR A1 - Bucher, Christian A1 - Frangopol, D.M. T1 - Optimization of lifetime maintenance strategies for deteriorting structures considering probabilities of violating safety, condition, and cost thresholds JF - Probabilistic Engineering Mechanics N2 - Optimization of lifetime maintenance strategies for deteriorting structures considering probabilities of violating safety, condition, and cost thresholds KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 1 EP - 8 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Brighenti, Roberto A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Optimization of fiber distribution in fiber reinforced composite by using NURBS functions JF - Computational Materials Science N2 - Optimization of fiber distribution in fiber reinforced composite by using NURBS functions KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 463 EP - 473 ER - TY - JOUR A1 - Bakar, I. A1 - Kramer, O. A1 - Bordas, Stéphane Pierre Alain A1 - Rabczuk, Timon T1 - Optimization of Elastic Properties and Weaving Patterns of Woven Composites JF - Composite Structures N2 - Optimization of Elastic Properties and Weaving Patterns of Woven Composites KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 SP - 575 EP - 591 ER - TY - JOUR A1 - Lahmer, Tom A1 - Könke, Carsten A1 - Bettzieche, Volker T1 - Optimale Positionierung von Messeinrichtungen an Staumauern zur Bauwerksüberwachung JF - WASSERWIRTSCHAFT N2 - Optimale Positionierung von Messeinrichtungen an Staumauern zur Bauwerksüberwachung KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2010 SP - 16 EP - 16 ER - TY - JOUR A1 - Brehm, Maik A1 - Zabel, Volkmar A1 - Bucher, Christian T1 - Optimal reference sensor positions for applications in model updating using output-only vibration test data based on random excitation: Part 2 - improved search strategy and experimental case study JF - Mechanical Systems and Signal Processing N2 - Optimal reference sensor positions for applications in model updating using output-only vibration test data based on random excitation: Part 2 - improved search strategy and experimental case study KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2011 ER - TY - JOUR A1 - Lahmer, Tom A1 - Könke, Carsten A1 - Bettzieche, Volker T1 - Optimal positioning of sensors for the monitoring of water dams JF - WASSERWIRTSCHAFT N2 - Optimal positioning of sensors for the monitoring of water dams KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2010 SP - 16 EP - 19 ER - TY - JOUR A1 - Lahmer, Tom A1 - Kaltenbacher, Barbara A1 - Schulz, V. T1 - Optimal measurement selection for piezoelectric material tensor identification JF - Inverse Problems in Science and Engineering N2 - Optimal measurement selection for piezoelectric material tensor identification. KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2008 U6 - http://dx.doi.org/10.25643/bauhaus-universitaet.3593 SP - 369 EP - 387 ER - TY - JOUR A1 - Lahmer, Tom T1 - Optimal experimental design for nonlinear ill-posed problems applied to gravity dams JF - Inverse Problems N2 - Optimal experimental design for nonlinear ill-posed problems applied to gravity dams KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2011 ER - TY - JOUR A1 - Talebi, Hossein A1 - Samaniego, C. A1 - Samaniego, Esteban A1 - Rabczuk, Timon T1 - On the numerical stability and mass-lumping schemes for explicit enriched meshfree methods JF - International Journal for Numerical Methods in Engineering N2 - Meshfree methods (MMs) such as the element free Galerkin (EFG)method have gained popularity because of some advantages over other numerical methods such as the finite element method (FEM). A group of problems that have attracted a great deal of attention from the EFG method community includes the treatment of large deformations and dealing with strong discontinuities such as cracks. One efficient solution to model cracks is adding special enrichment functions to the standard shape functions such as extended FEM, within the FEM context, and the cracking particles method, based on EFG method. It is well known that explicit time integration in dynamic applications is conditionally stable. Furthermore, in enriched methods, the critical time step may tend to very small values leading to computationally expensive simulations. In this work, we study the stability of enriched MMs and propose two mass-lumping strategies. Then we show that the critical time step for enriched MMs based on lumped mass matrices is of the same order as the critical time step of MMs without enrichment. Moreover, we show that, in contrast to extended FEM, even with a consistent mass matrix, the critical time step does not vanish even when the crack directly crosses a node. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1002/nme.3275 SP - 1009 EP - 1027 ER - TY - JOUR A1 - Silani, Mohammad A1 - Talebi, Hossein A1 - Arnold, Daniel A1 - Ziaei-Rad, S. A1 - Rabczuk, Timon T1 - On the coupling of a commercial finite element package with lammps for multiscale modeling of materials JF - Steel Research International N2 - On the coupling of a commercial finite element package with lammps for multiscale modeling of materials KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Bucher, Christian A1 - Pham, Hoang Anh T1 - On model updating of existing structures utilizing measured dynamic responses JF - Structure and Infrastructure Engineering N2 - On model updating of existing structures utilizing measured dynamic responses KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2005 SP - 135 EP - 143 ER - TY - JOUR A1 - Valizadeh, Navid A1 - Natarajan, S. A1 - Gonzalez-Estrada, O.A. A1 - Rabczuk, Timon A1 - Tinh Quoc, Bui A1 - Bordas, Stéphane Pierre Alain T1 - NURBS-based finite element analysis of functionally graded plates: static bending, vibration, buckling and flutter JF - Composite Structures N2 - NURBS-based finite element analysis of functionally graded plates: static bending, vibration, buckling and flutter KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 SP - 309 EP - 326 ER - TY - JOUR A1 - Bruhin, R. A1 - Stock, U.A. A1 - Drücker, J.-P. A1 - Azhari, T. A1 - Wippermann, J. A1 - Albes, J.M. A1 - Hintze, D. A1 - Eckardt, Stefan A1 - Könke, Carsten A1 - Wahlers, T. T1 - Numerical simulation techniques to study the structural response of the human chest following median sternotomy JF - The Annals of Thoracic Surgery N2 - Numerical simulation techniques to study the structural response of the human chest following median sternotomy KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2005 SP - 623 EP - 630 ER - TY - JOUR A1 - Kirichuk, A. A1 - Most, Thomas A1 - Bucher, Christian T1 - Numerical nonlinear analysis of kinematically excited shells JF - International Journal for Computational Civil and Structural Engineering N2 - Numerical nonlinear analysis of kinematically excited shells KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2003 SP - 61 EP - 74 ER - TY - JOUR A1 - Nguyen-Tuan, Long A1 - Könke, Carsten A1 - Bettzieche, Volker A1 - Lahmer, Tom T1 - Numerical modeling and validation for 3D coupled-nonlinear thermo-hydro-mechanical problems in masonry dams JF - Computers & Structures N2 - Numerical modeling and validation for 3D coupled-nonlinear thermo-hydro-mechanical problems in masonry dams KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 SP - 143 EP - 154 ER - TY - JOUR A1 - Band, Shahab S. A1 - Janizadeh, Saeid A1 - Chandra Pal, Subodh A1 - Saha, Asish A1 - Chakrabortty, Rabbin A1 - Shokri, Manouchehr A1 - Mosavi, Amir Hosein T1 - Novel Ensemble Approach of Deep Learning Neural Network (DLNN) Model and Particle Swarm Optimization (PSO) Algorithm for Prediction of Gully Erosion Susceptibility JF - Sensors N2 - This study aims to evaluate a new approach in modeling gully erosion susceptibility (GES) based on a deep learning neural network (DLNN) model and an ensemble particle swarm optimization (PSO) algorithm with DLNN (PSO-DLNN), comparing these approaches with common artificial neural network (ANN) and support vector machine (SVM) models in Shirahan watershed, Iran. For this purpose, 13 independent variables affecting GES in the study area, namely, altitude, slope, aspect, plan curvature, profile curvature, drainage density, distance from a river, land use, soil, lithology, rainfall, stream power index (SPI), and topographic wetness index (TWI), were prepared. A total of 132 gully erosion locations were identified during field visits. To implement the proposed model, the dataset was divided into the two categories of training (70%) and testing (30%). The results indicate that the area under the curve (AUC) value from receiver operating characteristic (ROC) considering the testing datasets of PSO-DLNN is 0.89, which indicates superb accuracy. The rest of the models are associated with optimal accuracy and have similar results to the PSO-DLNN model; the AUC values from ROC of DLNN, SVM, and ANN for the testing datasets are 0.87, 0.85, and 0.84, respectively. The efficiency of the proposed model in terms of prediction of GES was increased. Therefore, it can be concluded that the DLNN model and its ensemble with the PSO algorithm can be used as a novel and practical method to predict gully erosion susceptibility, which can help planners and managers to manage and reduce the risk of this phenomenon. KW - Geoinformatik KW - Maschinelles Lernen KW - gully erosion susceptibility KW - deep learning neural network KW - partical swarm optimization KW - OA-Publikationsfonds2020 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210122-43341 UR - https://www.mdpi.com/1424-8220/20/19/5609 VL - 2020 IS - Volume 20, issue 19, article 5609 SP - 1 EP - 27 PB - MDPI CY - Basel ER - TY - JOUR A1 - Ren, Huilong A1 - Zhuang, Xiaoying A1 - Oterkus, Erkan A1 - Zhu, Hehua A1 - Rabczuk, Timon T1 - Nonlocal strong forms of thin plate, gradient elasticity, magneto-electro-elasticity and phase-field fracture by nonlocal operator method JF - Engineering with Computers N2 - The derivation of nonlocal strong forms for many physical problems remains cumbersome in traditional methods. In this paper, we apply the variational principle/weighted residual method based on nonlocal operator method for the derivation of nonlocal forms for elasticity, thin plate, gradient elasticity, electro-magneto-elasticity and phase-field fracture method. The nonlocal governing equations are expressed as an integral form on support and dual-support. The first example shows that the nonlocal elasticity has the same form as dual-horizon non-ordinary state-based peridynamics. The derivation is simple and general and it can convert efficiently many local physical models into their corresponding nonlocal forms. In addition, a criterion based on the instability of the nonlocal gradient is proposed for the fracture modelling in linear elasticity. Several numerical examples are presented to validate nonlocal elasticity and the nonlocal thin plate. KW - Bruchmechanik KW - Elastizität KW - Peridynamik KW - energy form KW - weak form KW - peridynamics KW - variational principle KW - explicit time integration Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20211207-45388 UR - https://link.springer.com/article/10.1007/s00366-021-01502-8 VL - 2021 SP - 1 EP - 22 ER - TY - JOUR A1 - Zhang, Yongzheng T1 - Nonlocal dynamic Kirchhoff plate formulation based on nonlocal operator method JF - Engineering with Computers N2 - In this study, we propose a nonlocal operator method (NOM) for the dynamic analysis of (thin) Kirchhoff plates. The nonlocal Hessian operator is derived based on a second-order Taylor series expansion. The NOM does not require any shape functions and associated derivatives as ’classical’ approaches such as FEM, drastically facilitating the implementation. Furthermore, NOM is higher order continuous, which is exploited for thin plate analysis that requires C1 continuity. The nonlocal dynamic governing formulation and operator energy functional for Kirchhoff plates are derived from a variational principle. The Verlet-velocity algorithm is used for the time discretization. After confirming the accuracy of the nonlocal Hessian operator, several numerical examples are simulated by the nonlocal dynamic Kirchhoff plate formulation. KW - Angewandte Mathematik KW - nonlocal operator method KW - nonlocal Hessian operator KW - operator energy functional KW - dual-support KW - variational principle Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45849 UR - https://link.springer.com/article/10.1007/s00366-021-01587-1 VL - 2022 SP - 1 EP - 35 PB - Springer CY - London ER - TY - JOUR A1 - Lahmer, Tom A1 - Bock, Sebastian A1 - Hildebrand, Jörg A1 - Gürlebeck, Klaus T1 - Non-destructive identification of residual stresses in steel under thermal loadings JF - Inverse Problems in Science and Engineering N2 - Non-destructive identification of residual stresses in steel under thermal loadings KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 SP - 1 EP - 17 ER - TY - JOUR A1 - Bucher, Christian A1 - Ebert, Matthias T1 - Nichtlineare Berechnung von Stahlflanschverbindungen mit gemessenen Imperfektionen JF - Stahlbau N2 - Nichtlineare Berechnung von Stahlflanschverbindungen mit gemessenen Imperfektionen KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2002 SP - 516 EP - 522 ER - TY - JOUR A1 - Most, Thomas A1 - Bucher, Christian T1 - New concepts for moving least squares: An interpolating non-singular weighting function and weighted nodal least squares JF - Engineering Analysis with Boundary Elements N2 - New concepts for moving least squares: An interpolating non-singular weighting function and weighted nodal least squares KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2008 SP - 461 EP - 470 ER - TY - JOUR A1 - Arash, Behrouz A1 - Rabczuk, Timon A1 - Jiang, Jin-Wu T1 - Nanoresonators and their applications: a state of the art review JF - Applied Physics Reviews N2 - Nanoresonators and their applications: a state of the art review KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 ER - TY - JOUR A1 - Noori, Hamidreza A1 - Mortazavi, Bohayra A1 - Keshtkari, Leila A1 - Zhuang, Xiaoying A1 - Rabczuk, Timon T1 - Nanopore creation in MoS2 and graphene monolayers by nanoparticles impact: a reactive molecular dynamics study JF - Applied Physics A N2 - In this work, extensive reactive molecular dynamics simulations are conducted to analyze the nanopore creation by nano-particles impact over single-layer molybdenum disulfide (MoS2) with 1T and 2H phases. We also compare the results with graphene monolayer. In our simulations, nanosheets are exposed to a spherical rigid carbon projectile with high initial velocities ranging from 2 to 23 km/s. Results for three different structures are compared to examine the most critical factors in the perforation and resistance force during the impact. To analyze the perforation and impact resistance, kinetic energy and displacement time history of the projectile as well as perforation resistance force of the projectile are investigated. Interestingly, although the elasticity module and tensile strength of the graphene are by almost five times higher than those of MoS2, the results demonstrate that 1T and 2H-MoS2 phases are more resistive to the impact loading and perforation than graphene. For the MoS2nanosheets, we realize that the 2H phase is more resistant to impact loading than the 1T counterpart. Our reactive molecular dynamics results highlight that in addition to the strength and toughness, atomic structure is another crucial factor that can contribute substantially to impact resistance of 2D materials. The obtained results can be useful to guide the experimental setups for the nanopore creation in MoS2or other 2D lattices. KW - Nanomechanik KW - Molekülstruktur KW - Nanoporöser Stoff KW - MoS2 KW - molecular dynamics KW - Nanopore KW - Graphene Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210804-44756 UR - https://link.springer.com/article/10.1007/s00339-021-04693-5 VL - 2021 IS - volume 127, article 541 SP - 1 EP - 13 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Könke, Carsten A1 - Eckardt, Stefan A1 - Häfner, Stefan A1 - Luther, Torsten A1 - Unger, Jörg F. T1 - Multiscale simulation methods in damage prediction of brittle and ductile materials JF - International Journal for Multiscale Computational Engineering N2 - Multiscale simulation methods in damage prediction of brittle and ductile materials KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2010 SP - 17 EP - 36 ER - TY - JOUR A1 - Mortazavi, Bohayra A1 - Rabczuk, Timon T1 - Multiscale modeling of heat conduction in graphene laminates JF - Carbon N2 - Multiscale modeling of heat conduction in graphene laminates KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 1 EP - 7 ER - TY - JOUR A1 - Zhang, Chao A1 - Nanthakumar, S.S. A1 - Lahmer, Tom A1 - Rabczuk, Timon T1 - Multiple cracks identification for piezoelectric structures JF - International Journal of Fracture N2 - Multiple cracks identification for piezoelectric structures KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 SP - 1 EP - 19 ER - TY - JOUR A1 - Ilyani Akmar, A.B. A1 - Kramer, O. A1 - Rabczuk, Timon T1 - Multi-objective evolutionary optimization of sandwich structures: An evaluation by elitist non-dominated sorting evolution strategy JF - American Journal of Engineering and Applied Sciences N2 - In this study, an application of evolutionary multi-objective optimization algorithms on the optimization of sandwich structures is presented. The solution strategy is known as Elitist Non-Dominated Sorting Evolution Strategy (ENSES) wherein Evolution Strategies (ES) as Evolutionary Algorithm (EA) in the elitist Non-dominated Sorting Genetic algorithm (NSGA-II) procedure. Evolutionary algorithm seems a compatible approach to resolve multi-objective optimization problems because it is inspired by natural evolution, which closely linked to Artificial Intelligence (AI) techniques and elitism has shown an important factor for improving evolutionary multi-objective search. In order to evaluate the notion of performance by ENSES, the well-known study case of sandwich structures are reconsidered. For Case 1, the goals of the multi-objective optimization are minimization of the deflection and the weight of the sandwich structures. The length, the core and skin thicknesses are the design variables of Case 1. For Case 2, the objective functions are the fabrication cost, the beam weight and the end deflection of the sandwich structures. There are four design variables i.e., the weld height, the weld length, the beam depth and the beam width in Case 2. Numerical results are presented in terms of Paretooptimal solutions for both evaluated cases. KW - Optimierung KW - Stahlbau KW - Multi-objective Evolutionary Optimization, Elitist Non- Dominated Sorting Evolution Strategy (ENSES), Sandwich Structure, Pareto-Optimal Solutions, Evolutionary Algorithm Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170418-31402 SP - 185 EP - 201 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Park, Harold S. A1 - Rabczuk, Timon T1 - MoS2 nanoresonators: intrinsically better than graphene? JF - Nanoscale N2 - MoS2 nanoresonators: intrinsically better than graphene? KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 3618 EP - 3625 ER - TY - JOUR A1 - Talebi, Hossein A1 - Silani, Mohammad A1 - Bordas, Stéphane Pierre Alain A1 - Kerfriden, Pierre A1 - Rabczuk, Timon T1 - Molecular Dynamics/XFEM Coupling by a Three-Dimensional Extended Bridging Domain with Applications to Dynamic Brittle Fracture JF - International Journal for Multiscale Computational Engineering N2 - Molecular Dynamics/XFEM Coupling by a Three-Dimensional Extended Bridging Domain with Applications to Dynamic Brittle Fracture KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Modulation of Thermal Conductivity in kinked Silicon Nanowires: Phonon interchanging and pinching effects or Reduction of thermal conductivity in kinked silicon nanowire superlattices JF - Nano Letters N2 - Modulation of Thermal Conductivity in kinked Silicon Nanowires: Phonon interchanging and pinching effects or Reduction of thermal conductivity in kinked silicon nanowire superlattices KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Lahmer, Tom T1 - Modified Landweber iterations in a multilevel algorithm applied to inverse problems in piezoelectricity JF - Journal of Inverse and Ill-posed Problems N2 - Modified Landweber iterations in a multilevel algorithm applied to inverse problems in piezoelectricity KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2009 SP - 585 EP - 593 ER - TY - JOUR A1 - Unger, Jörg F. A1 - Eckardt, Stefan A1 - Könke, Carsten T1 - Modelling of cohesive crack growth in concrete structures with the extended finite element method JF - Computer Methods in Applied Mechanics and Engineering N2 - Modelling of cohesive crack growth in concrete structures with the extended finite element method KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2007 SP - 4087 EP - 4100 ER - TY - JOUR A1 - Mortazavi, Bohayra A1 - Pereira, Luiz Felipe C. A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Modelling heat conduction in polycrystalline hexagonal boron-nitride films JF - Scientific Reports N2 - We conducted extensive molecular dynamics simulations to investigate the thermal conductivity of polycrystalline hexagonal boron-nitride (h-BN) films. To this aim, we constructed large atomistic models of polycrystalline h-BN sheets with random and uniform grain configuration. By performing equilibrium molecular dynamics (EMD) simulations, we investigated the influence of the average grain size on the thermal conductivity of polycrystalline h-BN films at various temperatures. Using the EMD results, we constructed finite element models of polycrystalline h-BN sheets to probe the thermal conductivity of samples with larger grain sizes. Our multiscale investigations not only provide a general viewpoint regarding the heat conduction in h-BN films but also propose that polycrystalline h-BN sheets present high thermal conductivity comparable to monocrystalline sheets. KW - Wärmeleitfähigkeit KW - Bornitrid KW - Finite-Elemente-Methode Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170425-31534 ER - TY - JOUR A1 - Meiabadi, Mohammad Saleh A1 - Moradi, Mahmoud A1 - Karamimoghadam, Mojtaba A1 - Ardabili, Sina A1 - Bodaghi, Mahdi A1 - Shokri, Manouchehr A1 - Mosavi, Amir Hosein T1 - Modeling the Producibility of 3D Printing in Polylactic Acid Using Artificial Neural Networks and Fused Filament Fabrication JF - polymers N2 - Polylactic acid (PLA) is a highly applicable material that is used in 3D printers due to some significant features such as its deformation property and affordable cost. For improvement of the end-use quality, it is of significant importance to enhance the quality of fused filament fabrication (FFF)-printed objects in PLA. The purpose of this investigation was to boost toughness and to reduce the production cost of the FFF-printed tensile test samples with the desired part thickness. To remove the need for numerous and idle printing samples, the response surface method (RSM) was used. Statistical analysis was performed to deal with this concern by considering extruder temperature (ET), infill percentage (IP), and layer thickness (LT) as controlled factors. The artificial intelligence method of artificial neural network (ANN) and ANN-genetic algorithm (ANN-GA) were further developed to estimate the toughness, part thickness, and production-cost-dependent variables. Results were evaluated by correlation coefficient and RMSE values. According to the modeling results, ANN-GA as a hybrid machine learning (ML) technique could enhance the accuracy of modeling by about 7.5, 11.5, and 4.5% for toughness, part thickness, and production cost, respectively, in comparison with those for the single ANN method. On the other hand, the optimization results confirm that the optimized specimen is cost-effective and able to comparatively undergo deformation, which enables the usability of printed PLA objects. KW - 3D-Druck KW - Polymere KW - Maschinelles Lernen KW - 3D printing KW - machine learning KW - fused filament fabrication KW - OA-Publikationsfonds2021 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220110-45518 UR - https://www.mdpi.com/2073-4360/13/19/3219 VL - 2021 IS - Volume 13, issue 19, article 3219 SP - 1 EP - 21 PB - MDPI CY - Basel ER - TY - JOUR A1 - Shabani, Sevda A1 - Samadianfard, Saeed A1 - Sattari, Mohammad Taghi A1 - Mosavi, Amir A1 - Shamshirband, Shahaboddin A1 - Kmet, Tibor A1 - Várkonyi-Kóczy, Annamária R. T1 - Modeling Pan Evaporation Using Gaussian Process Regression K-Nearest Neighbors Random Forest and Support Vector Machines; Comparative Analysis JF - Atmosphere N2 - Evaporation is a very important process; it is one of the most critical factors in agricultural, hydrological, and meteorological studies. Due to the interactions of multiple climatic factors, evaporation is considered as a complex and nonlinear phenomenon to model. Thus, machine learning methods have gained popularity in this realm. In the present study, four machine learning methods of Gaussian Process Regression (GPR), K-Nearest Neighbors (KNN), Random Forest (RF) and Support Vector Regression (SVR) were used to predict the pan evaporation (PE). Meteorological data including PE, temperature (T), relative humidity (RH), wind speed (W), and sunny hours (S) collected from 2011 through 2017. The accuracy of the studied methods was determined using the statistical indices of Root Mean Squared Error (RMSE), correlation coefficient (R) and Mean Absolute Error (MAE). Furthermore, the Taylor charts utilized for evaluating the accuracy of the mentioned models. The results of this study showed that at Gonbad-e Kavus, Gorgan and Bandar Torkman stations, GPR with RMSE of 1.521 mm/day, 1.244 mm/day, and 1.254 mm/day, KNN with RMSE of 1.991 mm/day, 1.775 mm/day, and 1.577 mm/day, RF with RMSE of 1.614 mm/day, 1.337 mm/day, and 1.316 mm/day, and SVR with RMSE of 1.55 mm/day, 1.262 mm/day, and 1.275 mm/day had more appropriate performances in estimating PE values. It was found that GPR for Gonbad-e Kavus Station with input parameters of T, W and S and GPR for Gorgan and Bandar Torkmen stations with input parameters of T, RH, W and S had the most accurate predictions and were proposed for precise estimation of PE. The findings of the current study indicated that the PE values may be accurately estimated with few easily measured meteorological parameters. KW - Maschinelles Lernen KW - Machine learning KW - Deep learning Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20200110-40561 UR - https://www.mdpi.com/2073-4433/11/1/66 VL - 2020 IS - Volume 11, Issue 1, 66 ER - TY - JOUR A1 - Kumar, S. A1 - Singh, I. A1 - Mishra, B.K. A1 - Rabczuk, Timon T1 - Modeling and Simulation of Kinked Cracks by Virtual Node XFEM JF - Computer Methods in Applied Mechanics and Engineering N2 - Modeling and Simulation of Kinked Cracks by Virtual Node XFEM KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 1425 EP - 1466 ER - TY - JOUR A1 - Abdelnour, Mena A1 - Zabel, Volkmar T1 - Modal identification of structures with a dynamic behaviour characterised by global and local modes at close frequencies JF - Acta Mechanica N2 - Identification of modal parameters of a space frame structure is a complex assignment due to a large number of degrees of freedom, close natural frequencies, and different vibrating mechanisms. Research has been carried out on the modal identification of rather simple truss structures. So far, less attention has been given to complex three-dimensional truss structures. This work develops a vibration-based methodology for determining modal information of three-dimensional space truss structures. The method uses a relatively complex space truss structure for its verification. Numerical modelling of the system gives modal information about the expected vibration behaviour. The identification process involves closely spaced modes that are characterised by local and global vibration mechanisms. To distinguish between local and global vibrations of the system, modal strain energies are used as an indicator. The experimental validation, which incorporated a modal analysis employing the stochastic subspace identification method, has confirmed that considering relatively high model orders is required to identify specific mode shapes. Especially in the case of the determination of local deformation modes of space truss members, higher model orders have to be taken into account than in the modal identification of most other types of structures. KW - Fachwerkbau KW - Holzkonstruktion KW - Schwingung KW - three-dimensional truss structures KW - vibration-based methodology KW - numerical modelling Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230525-63822 UR - https://link.springer.com/article/10.1007/s00707-023-03598-z VL - 2023 SP - 1 EP - 21 PB - Springer CY - Wien ER - TY - JOUR A1 - Häfner, Stefan A1 - Eckardt, Stefan A1 - Luther, Torsten A1 - Könke, Carsten T1 - Mesoscale modeling of concrete: Geometry and numerics JF - Computers and Structures N2 - Mesoscale modeling of concrete: Geometry and numerics KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 450 EP - 461 ER - TY - JOUR A1 - Zhao, Jun-Hua A1 - Wei, Ning A1 - Fan, Z. A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Mechanical properties of three types of carbon allotropes JF - Nanotechnology N2 - Mechanical properties of three types of carbon allotropes KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Mortazavi, Bohayra A1 - Cuniberti, G. A1 - Rabczuk, Timon T1 - Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study JF - Computational Materials Science N2 - Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 285 EP - 289 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring JF - Applied Physics Letters N2 - Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Mosavi, Amir Hosein A1 - Shokri, Manouchehr A1 - Mansor, Zulkefli A1 - Qasem, Sultan Noman A1 - Band, Shahab S. A1 - Mohammadzadeh, Ardashir T1 - Machine Learning for Modeling the Singular Multi-Pantograph Equations JF - Entropy N2 - In this study, a new approach to basis of intelligent systems and machine learning algorithms is introduced for solving singular multi-pantograph differential equations (SMDEs). For the first time, a type-2 fuzzy logic based approach is formulated to find an approximated solution. The rules of the suggested type-2 fuzzy logic system (T2-FLS) are optimized by the square root cubature Kalman filter (SCKF) such that the proposed fineness function to be minimized. Furthermore, the stability and boundedness of the estimation error is proved by novel approach on basis of Lyapunov theorem. The accuracy and robustness of the suggested algorithm is verified by several statistical examinations. It is shown that the suggested method results in an accurate solution with rapid convergence and a lower computational cost. KW - Fuzzy-Regelung KW - square root cubature calman filter KW - statistical analysis KW - OA-Publikationsfonds2020 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210122-43436 UR - https://www.mdpi.com/1099-4300/22/9/1041 VL - 2020 IS - volume 22, issue 9, article 1041 SP - 1 EP - 18 PB - MDPI CY - Basel ER - TY - JOUR A1 - Zhang, Yancheng A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Mabrouki, Tarek A1 - Fontaine, Michaël A1 - Gong, Yadong A1 - Rabczuk, Timon T1 - Load transfer of graphene/carbon nanotube/polyethylene hybrid nanocomposite by molecular dynamics simulation JF - Composites Part B Engineering N2 - Load transfer of graphene/carbon nanotube/polyethylene hybrid nanocomposite by molecular dynamics simulation KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 27 EP - 33 ER -