TY - THES
A1 - Kavrakov, Igor
T1 - Structural Optimization of Composite Cross-Sections and Elements using Energy Methods
N2 - Structural optimization has gained considerable attention in the design of structural engineering structures, especially in the preliminary phase.
This study introduces an unconventional approach for structural optimization by utilizing the Energy method with Integral Material Behavior (EIM), based on the Lagrange’s principle of minimum potential energy. An automated two-level optimization search process is proposed, which integrates the EIM, as an alternative method for nonlinear
structural analysis, and the bilevel optimization. The proposed procedure secures the equilibrium through minimizing the potential energy on one level, and on a higher level, a design objective function. For this, the most robust strategy of bilevel optimization, the nested method is used. The function of the potential energy is investigated along with its instabilities for physical nonlinear analysis through principle examples, by which the advantages and limitations using this method are reviewed. Furthermore, optimization algorithms are discussed.
A numerical fully functional code is developed for nonlinear cross section,
element and 2D frame analysis, utilizing different finite elements and is verified
against existing EIM programs. As a proof of concept, the method is applied on selected
examples using this code on cross section and element level. For the former one a
comparison is made with standard procedure, by employing the equilibrium equations
within the constrains. The validation of the element level was proven by a theoretical
solution of an arch bridge and finally, a truss bridge is optimized. Most of the
principle examples are chosen to be adequate for the everyday engineering practice, to
demonstrate the effectiveness of the proposed method.
This study implies that with further development, this method could become just as
competitive as the conventional structural optimization techniques using the Finite
Element Method.
KW - Strukturoptimierung
Y1 - 2014
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20190815-39593
ER -
TY - JOUR
A1 - Völker, Conrad
A1 - Mämpel, Silvio
A1 - Kornadt, Oliver
T1 - Measuring the human body’s micro‐climate using a thermal manikin
JF - Indoor Air
N2 - The human body is surrounded by a micro‐climate which results from its convective release of heat. In this study, the air temperature and flow velocity of this micro‐climate were measured in a climate chamber at various room temperatures, using a thermal manikin simulating the heat release of the human being. Different techniques (Particle Streak Tracking, thermography, anemometry, and thermistors) were used for measurement and visualization. The manikin surface temperature was adjusted to the particular indoor climate based on simulations with a thermoregulation model (UCBerkeley Thermal Comfort Model). We found that generally, the micro‐climate is thinner at the lower part of the torso, but expands going up. At the head, there is a relatively thick thermal layer, which results in an ascending plume above the head. However, the micro‐climate shape strongly depends not only on the body segment, but also on boundary conditions: the higher the temperature difference between the surface temperature of the manikin and the air temperature, the faster the air flow in the micro‐climate. Finally, convective heat transfer coefficients strongly increase with falling room temperature, while radiative heat transfer coefficients decrease. The type of body segment strongly influences the convective heat transfer coefficient, while only minimally influencing the radiative heat transfer coefficient.
KW - Raumklima
KW - Mikroklima
KW - Wärmeübertragung
KW - Strömungsmechanik
KW - thermal manikin
KW - climate chamber
KW - micro climate
KW - heat transfer coefficient
KW - CFD
KW - thermography
Y1 - 2014
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20181025-38153
UR - https://onlinelibrary.wiley.com/doi/abs/10.1111/ina.12112
N1 - This is the peer reviewed version of the following article: "Measuring the human body’s micro‐climate using a thermal
manikin", which has been published in final form at https://doi.org/10.1111/ina.12112. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
IS - 24, 6
SP - 567
EP - 579
ER -
TY - CHAP
A1 - Schwedler, Michael
A1 - Könke, Carsten
T1 - Integrierte Tragwerksanalysen mittels Bauwerksinformationsmodellen und isogeometrischer FE-Methoden
N2 - Integrierte Tragwerksanalysen mittels Bauwerksinformationsmodellen und isogeometrischer FE-Methoden
KW - Angewandte Mathematik
KW - Strukturmechanik
Y1 - 2014
SN - 978-3-00-041256-1
ER -
TY - CHAP
A1 - Hatahet, Tareq
A1 - Könke, Carsten
T1 - Rational Framework for Probability of Collapse in Buildings
N2 - Rational Framework for Probability of Collapse in Buildings
KW - Angewandte Mathematik
KW - Strukturmechanik
Y1 - 2014
ER -
TY - JOUR
A1 - Zhuang, Xiaoying
A1 - Huang, Runqiu
A1 - Rabczuk, Timon
A1 - Liang, C.
T1 - A coupled thermo-hydro-mechanical model of jointed hard rock for compressed air energy storage
JF - Mathematical Problems in Engineering
N2 - A coupled thermo-hydro-mechanical model of jointed hard rock for compressed air energy storage
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 - Thai, Chien H.
A1 - Ferreira, A.J.M.
A1 - Bordas, Stéphane Pierre Alain
A1 - Rabczuk, Timon
A1 - Nguyen-Xuan, Hung
T1 - Isogeometric analysis of laminated composite and sandwich plates using a new inverse trigonometric shear deformation theory
JF - European Journal of Mechanics
N2 - Isogeometric analysis of laminated composite and sandwich plates using a new inverse trigonometric shear deformation theory
KW - Angewandte Mathematik
KW - Strukturmechanik
Y1 - 2014
SP - 89
EP - 108
ER -
TY - JOUR
A1 - Nanthakumar, S.S.
A1 - Lahmer, Tom
A1 - Rabczuk, Timon
T1 - Detection of multiple flaws in piezoelectric structures using XFEM and level sets
JF - Computer Methods in Applied Mechanics and Engineering
N2 - Detection of multiple flaws in piezoelectric structures using XFEM and level sets
KW - Angewandte Mathematik
KW - Stochastik
KW - Strukturmechanik
Y1 - 2014
SP - 98
EP - 112
ER -
TY - JOUR
A1 - Chen, Lei
A1 - Nguyen-Thanh, Nhon
A1 - Nguyen-Xuan, Hung
A1 - Rabczuk, Timon
A1 - Bordas, Stéphane Pierre Alain
A1 - Limbert, Georges
T1 - Explicit finite deformation analysis of isogeometric membranes
JF - Computer Methods in Applied Mechanics and Engineering
N2 - Explicit finite deformation analysis of isogeometric membranes
KW - Angewandte Mathematik
KW - Strukturmechanik
Y1 - 2014
SP - 104
EP - 130
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 -