Stress Analysis and Identification with Full-Field Measurements

2006 ◽  
Vol 3-4 ◽  
pp. 9-16 ◽  
Author(s):  
M. Grédiac
Keyword(s):  
Model Updating ◽  
Measurement Techniques ◽  
Field Measurements ◽  
Element Model ◽  
Finite Element Model Updating ◽  
Strain Fields ◽  
Full Field ◽  
Full Field Measurement ◽  
Constitutive Parameters ◽  
The Finite Element Model

The wealth of information provided by full-field measurement techniques is very useful in experimental mechanics. Among different possible applications, full-field measurements can be used to identify parameters governing constitutive equations from heterogeneous strain fields. This keynote lecture first describes the different possible uses of such measurements. It then focuses on the virtual fields method which has been proposed to extract constitutive parameters from full-field measurements. Finally, the method is compared with the finite element model updating technique which is usually used for solving such a problem.

scholarly journals Identification of Local Elastic Parameters in Heterogeneous Materials Using a Parallelized Femu Method

2019 ◽  
Vol 24 (4) ◽  
pp. 140-156
Author(s):  
L. Petureau ◽  
P. Doumalin ◽  
F. Bremand
Keyword(s):  
Genetic Algorithm ◽  
Model Updating ◽  
Heterogeneous Materials ◽  
Element Model ◽  
Finite Element Model Updating ◽  
Elastic Parameters ◽  
Displacement Fields ◽  
Quadratic Error ◽  
Strain Fields ◽  
Computation Cost

Abstract In this work, we explore the possibilities of the widespread Finite Element Model Updating method (FEMU) in order to identify the local elastic mechanical properties in heterogeneous materials. The objective function is defined as a quadratic error of the discrepancy between measured fields and simulated ones. We compare two different formulations of the function, one based on the displacement fields and one based on the strain fields. We use a genetic algorithm in order to minimize these functions. We prove that the strain functional associated with the genetic algorithm is the best combination. We then improve the implementation of the method by parallelizing the algorithm in order to reduce the computation cost. We validate the approach with simulated cases in 2D.

scholarly journals Identification of Materials Properties Using Displacement Field Measurement

2011 ◽  
Vol 482 ◽  
pp. 57-65 ◽  
Author(s):  
Marina Fazzini ◽  
Olivier Dalverny ◽  
Sébastien Mistou
Keyword(s):  
Finite Element ◽  
Displacement Field ◽  
Model Updating ◽  
Virtual Work ◽  
Field Measurements ◽  
Element Model ◽  
Field Method ◽  
Element Analysis ◽  
Virtual Field ◽  
Constitutive Parameters

The aim of this work is to identify parameters driving constitutive equations of materials with displacement field measurements carried out by image stereo-correlation during an unidirectional tensile test. We evaluate two identification techniques. The first one is the virtual fields method which consists in writing the principle of virtual work with particular virtual fields. It is generally used in the case of linear elasticity and it requires a perfect knowledge of the model in terms of boundary condition since the virtual fields used must be kinematically admissible. This method allows to determine parameters by a direct and fast calculation, without iterations. The second method is the finite element model updating method. It consists in finding constitutive parameters that achieve the best match between finite element analysis quantities and their experimental counterparts. This method is more adaptable than the virtual field method but it needs to spend more calculation time.

Finite element model updating from full-field vibration measurement using digital image correlation

2011 ◽  
Vol 330 (8) ◽  
pp. 1599-1620 ◽  
Author(s):  
Weizhuo Wang ◽  
John E. Mottershead ◽  
Alexander Ihle ◽  
Thorsten Siebert ◽  
Hans Reinhard Schubach
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Finite Element Model ◽  
Digital Image ◽  
Model Updating ◽  
Element Model ◽  
Image Correlation ◽  
Vibration Measurement ◽  
Finite Element Model Updating ◽  
Full Field

Identification of a 3D Anisotropic Yield Surface of X70 Pipeline Steel Using a Multi-DIC Setup

2016 ◽  
Author(s):  
Kristof Denys ◽  
Sam Coppieters ◽  
Renaat Van Hecke ◽  
Steven Cooreman ◽  
Dimitri Debruyne
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Model Updating ◽  
Element Model ◽  
Image Correlation ◽  
Finite Element Model Updating ◽  
Line Pipe ◽  
Strain Fields ◽  
Stereo Digital Image Correlation

A new method is proposed combining multiple synchronized digital image correlation setups (multi-DIC) and finite element model updating to identify the hardening behaviour and anisotropy of 23.5 mm thick X70 line pipe steel. Curved tensile samples have been cut from a coil. While performing a tensile test on those samples, the force was obtained from the load cell and the back and front surface strain fields were measured by means of two synchronized stereo digital image correlation setups. The tests on the curved samples are reproduced with FE simulations, applying the same boundary conditions as the experimental setup to obtain the numerical force and strain fields. While simultaneously minimising the discrepancy between the experimentally and numerically obtained force and strain fields, the strain hardening behaviour is identified beyond the point of maximum uniform elongation. A profound understanding of the anisotropy is also mandatory because the hot rolling operation develops substantial anisotropy which has an important influence on the line pipe performance. Due to the 23.5 mm thick steel that is used in this work, it is possible to measure the front and side surfaces with two synchronized stereo digital image correlation setups. Because full field information is available in all 3 material directions (lateral, longitudinal and through thickness direction), a 3D anisotropic yield criterion can be identified. A prerequisite for stable and accurate identification of the yield locus parameters is that the governing parameters are sufficiently sensitive to the experimentally measured response. For this purpose, a double perforated specimen has been designed which includes a side perforation. The latter guarantees the necessary through-thickness information to inversely identify the 3D anisotropic yield function through multi-DIC and finite element model updating. The presented procedure could potentially be used by line pipe manufactures to verify whether the mechanical properties meet the specified requirements. The proposed approach has some advantages compared to conventional methods to determine mechanical properties of large diameter pipe. The curved specimen geometry is modelled in the FE simulation, hence the detrimental effects of flatting the tensile specimen can be avoided. Further, the new approach enables to consider the complete wall thickness as opposed to conventional testing with round bar samples of which a part of the wall thickness is removed during manufacturing.

scholarly journals Shape features and finite element model updating from full-field strain data

2011 ◽  
Vol 48 (11-12) ◽  
pp. 1644-1657 ◽  
Author(s):  
Weizhuo Wang ◽  
John E. Mottershead ◽  
Christopher M. Sebastian ◽  
Eann A. Patterson
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Field Strain ◽  
Finite Element Model Updating ◽  
Shape Features ◽  
Full Field ◽  
Strain Data
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