In English

Finite Element Model Calibration with Digital Image Correlation

Lotta Bergbom
Göteborg : Chalmers tekniska högskola, 2018. 66 s.
[Examensarbete på avancerad nivå]

Finite Element (FE) models are widely used to predict the mechanical behaviour of materials and components when subjected to different loads. In the industry, this is a valuable way to reduce the number of physical experiments and, thereby, costs when developing new products. With many actors trying to become more material efficient, new materials with sometimes complex structures are employed or the limits of how much the material is loaded are pushed. As a consequence of this, the need for adequate and accurate material models in the FE modelling increases. Digital Image Correlation(DIC) is a non-contact measurement technique used to measure displacements and strains locally on a surface in space and time. The goal of this thesis is to use DIC data to calibrate some typical material models used in FE modelling. The value and potential of the proposed calibration method is evaluated. The work is performed in collaboration with Research Institutes of Sweden AB (RISE) who has extensive experience with physical experiments, modelling and DIC. As there already existed test results from tensile tests made of steel, these were used when developing the calibration method. For later applications more complicated material models are of interest but for concept testing, the choice of material model is less important and therefore the relatively simple linear isotropic elasticity and von Mises plasticity with linear hardening are chosen. The work was mainly divided into two parts. The first part consisted of examining the experimental data obtained from DIC as a means for pre-processing and analysis of the data quality. The second part of the work was concentrated on constructing FE models whose results could be compared to the available experimental data and to calibrate the material models by using an optimising method. In order to assess the calibration method and how it is affected by different prerequisites, different case studies were carried out. The aim of the case studies was to investigate how different assumptions of the material model and of the FE modelling affected the results and thereby also giving an indication of the calibration method’s robustness. This thesis therefore provides an idea of how this calibration method could work and what potential it has by showing some of the potential pitfalls to avoid when developing the method further. Since the developed method is material model independent, more advanced materials and models could be evaluated in the future.

Nyckelord: digital image correlation, material model calibration, finite element modelling

Publikationen registrerades 2018-07-04. Den ändrades senast 2018-07-04

CPL ID: 255486

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