Improving efficiency and robustness of enhanced assumed strain elements for nonlinear problems

Autor: Robin Pfefferkorn, Manfred Bischoff, Simon Bieber, Peter Betsch, Bastian Oesterle
Rok vydání: 2021
Předmět:
Zdroj: International journal for numerical methods in engineering, 122 (8), 1911-1939
ISSN: 1097-0207
0029-5981
DOI: 10.1002/nme.6605
Popis: The enhanced assumed strain (EAS) method is one of the most frequently used methods to avoid locking in solid and structural finite elements. One issue of EAS elements in the context of geometrically nonlinear analyses is their lack of robustness in the Newton–Raphson scheme, which is characterized by the necessity of small load increments and large number of iterations. In the present work we extend the recently proposed mixed integration point (MIP) method to EAS elements in order to overcome this drawback in numerous applications. Furthermore, the MIP method is generalized to generic material models, which makes this simple method easily applicable for a broad class of problems. In the numerical simulations in this work, we compare standard strain‐based EAS elements and their MIP improved versions to elements based on the assumed stress method in order to explain when and why the MIP method allows to improve robustness. A further novelty in the present work is an inverse stress‐strain relation for a Neo‐Hookean material model.
Databáze: OpenAIRE
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