Workshop on "Plasticity, Damage and Fracture of Engineering Materials", Ankara, Türkiye, 25 Ekim 2018, ss.9
This paper presents a novel approach for comparison of constitutive models for
rubber. Model parameters are identified by simultaneous fitting of a given data of a set of
homogeneous experiments (uniaxial tension, equibiaxial tension, and pure shear, Figure 1) by
multiobjective optimization. Using these parameters, fitting error can be calculated. In this
study, however, quality of fit parameter, which represents the amount of error normalized by
the data, is calculated for unbiased comparison of models. 40 different constitutive models for
rubber-like materials from the literature are compared based on their quality of fit values [1].
Among these models, micro-sphere [2] and Alexander’s model [3] gives the best results for
simultaneous fitting. However, some models work in low or moderate stretch levels. The stretch
values up to which a model performs reasonably good (in terms of quality of fit) is called
validity range. It allows ranged comparison of models and provides insight for model selection
in engineering practice. Quality of fit values, validity ranges and errors are presented for all 40
models.