Effect of strain rate sensitivity in visco-plastic modeling. (November 2018)

• Record Type: Journal Article
• Authors: Chapuis, Adrien; Liu, Qing
• Is Part Of: International journal of solids and structures. Volume 152/153(2018)
• Page Start: 217
• Page End: 227
• Publication Date: 2018-11
• Subjects: Crystal plasticity -- Viscoplastic material; Mechanics, Applied -- Periodicals; Structural analysis (Engineering) -- Periodicals; Elastic solids -- Periodicals; Mécanique appliquée -- Périodiques; Constructions, Théorie des -- Périodiques; Solides élastiques -- Périodiques; Elastic solids; Mechanics, Applied; Structural analysis (Engineering); Periodicals; 624.18
• DOI: 10.1016/j.ijsolstr.2018.06.029
• Languages: English
• ISSNs: 0020-7683

Abstract

Abstract: Many crystal plasticity models use a rate sensitive law for its convenience. The rate sensitivity can be determined experimentally and input in the models. From a numerical point of view, high values of the strain rate sensitivity parameter m favor easy convergence of these models, but when m is fixed arbitrarily, which is in practice done for slightly rate sensitive materials, the physical meaning of m is lost. The present study shows that the flow stress σ, slip systems activity γ s, strain anisotropy and simulated texture are strongly dependent on m . Precautions should be taken when predicting the mechanical behavior of polycrystals. To simulate nearly rate insensitive materials with models using a rate sensitive law, the use of the reference shear strain γ ˙ 0 equal to the imposed strain rate is necessary but not sufficient. It is also necessary to use a high strain rate sensitivity parameter ( m = 0.05) to correctly evaluate the material parameters, i.e., the critical resolved shear stresses (CRSS). This study also provides a relationship between the CRSS determined for different values of strain rate ɛ ˙, m and γ ˙ 0, so that CRSS determined in different studies can be compared.