TY  - JOUR
A1  - Reichert, Ina
A1  - Olney, Peter
A1  - Lahmer, Tom
T1  - Combined approach for optimal sensor placement and experimental verification in the context of tower-like structures
JF  - Journal of Civil Structural Health Monitoring
N2  - When it comes to monitoring of huge structures, main issues are limited time, high costs and how to deal with the big amount of data. In order to reduce and manage them, respectively, methods from the field of optimal design of experiments are useful and supportive. Having optimal experimental designs at hand before conducting any measurements is leading to a highly informative measurement concept, where the sensor positions are optimized according to minimal errors in the structures’ models. For the reduction of computational time a combined approach using Fisher Information Matrix and mean-squared error in a two-step procedure is proposed under the consideration of different error types. The error descriptions contain random/aleatoric and systematic/epistemic portions. Applying this combined approach on a finite element model using artificial acceleration time measurement data with artificially added errors leads to the optimized sensor positions. These findings are compared to results from laboratory experiments on the modeled structure, which is a tower-like structure represented by a hollow pipe as the cantilever beam. Conclusively, the combined approach is leading to a sound experimental design that leads to a good estimate of the structure’s behavior and model parameters without the need of preliminary measurements for model updating.
KW  - Strukturmechanik
KW  - Finite-Elemente-Methode
KW  - tower-like structures
KW  - experimental validation
KW  - mean-squared error
KW  - fisher-information matrix
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210804-44701
UR  - https://link.springer.com/article/10.1007/s13349-020-00448-7
VL  - 2021
IS  - volume 11
SP  - 223
EP  - 234
PB  - Heidelberg
CY  - Springer
ER  - 
TY  - JOUR
A1  - Ataollahi Oshkour, Azim
A1  - Talebi, Hossein
A1  - Seyed Shirazi, Seyed Farid
A1  - Bayat, Mehdi
A1  - Yau, Yat Huang
A1  - Tarlochan, Faris
A1  - Abu Osman, Noor Azuan
T1  - Comparison of various functionally graded femoral prostheses by finite element analysis
JF  - Scientific World Journal
N2  - This study is focused on finite element analysis of a model comprising femur into which a femoral component of a total hip replacement was implanted. The considered prosthesis is fabricated from a functionally graded material (FGM) comprising a layer of a titanium alloy bonded to a layer of hydroxyapatite. The elastic modulus of the FGM was adjusted in the radial, longitudinal, and longitudinal-radial directions by altering the volume fraction gradient exponent. Four cases were studied, involving two different methods of anchoring the prosthesis to the spongy bone and two cases of applied loading. The results revealed that the FG prostheses provoked more SED to the bone. The FG prostheses carried less stress, while more stress was induced to the bone and cement. Meanwhile, less shear interface stress was stimulated to the prosthesis-bone interface in the noncemented FG prostheses. The cement-bone interface carried more stress compared to the prosthesis-cement interface. Stair climbing induced more harmful effects to the implanted femur components compared to the normal walking by causing more stress. Therefore, stress shielding, developed stresses, and interface stresses in the THR components could be adjusted through the controlling stiffness of the FG prosthesis by managing volume fraction gradient exponent.
KW  - Finite-Elemente-Methode
KW  - Hüftgelenk
KW  - Funktioneller Gradientenwerkstoff
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170413-31194
ER  -