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Identification of material parameters in extended contiuum mechanicalmodels
Author(s) -
Chatzouridou Anthippi,
Diebels Stefan
Publication year - 2005
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200510224
Subject(s) - boundary value problem , constitutive equation , inverse problem , inverse , statistical physics , materials science , work (physics) , mechanics , mathematics , physics , finite element method , mathematical analysis , thermodynamics , geometry
A method for the identification of material parameters of constitutive models describing foamed materials is discussed in the present work. One can model foamed materials in two ways: using a lattice‐like micro‐model or alternatively a continuum mechanical approach. A beam model is used for the description of foams on a microscopic scale and alternatively an extended continuum model based on the Cosserat theory is employed on the macroscopic scale. By performing numerical shear tests at specimens of different sizes, we can observe the following effect on both models: The distribution of the rotations shows a strong boundary layer character at the top and bottom boundary of the specimen, whereas at the inner part it takes a constant value. These boundary layer effects do not scale with the size of the specimen, as a result specimens occur to be stiffer, see [1]. The goal is to perform a fitting of the Cosserat parameters by comparing the results of the macroscopic model to these of the microscopic one. The parameter fitting concerns an inverse problem which is treated within the framework of stochastic optimization methods. An evolutionary algorithm is used in combination with a response surface method for the identification of the material parameters. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)