A Cartesian parametrization for the numerical analysis of material instability. (25th February 2016)

• Record Type: Journal Article
• Authors: Mota, A.; Chen, Q.; Foulk, J.W.; Ostien, J.T.; Lai, Z.
• Is Part Of: International journal for numerical methods in engineering. Volume 108:Number 2(2016)
• Page Start: 156
• Page End: 180
• Publication Date: 2016-02-25
• Subjects: material stability -- constitutive equations -- Newton methods -- variational methods; Numerical analysis -- Periodicals; Engineering mathematics -- Periodicals; 620.001518
• DOI: 10.1002/nme.5228
• Languages: English
• ISSNs: 0029-5981

Abstract

Summary: We examine four parametrizations of the unit sphere in the context of material stability analysis by means of the singularity of the acoustic tensor. We then propose a Cartesian parametrization for vectors that lie a cube of side length two and use these vectors in lieu of unit normals to test for the loss of the ellipticity condition. This parametrization is then used to construct a tensor akin to the acoustic tensor. It is shown that both of these tensors become singular at the same time and in the same planes in the presence of a material instability. The performance of the Cartesian parametrization is compared against the other parametrizations, with the results of these comparisons showing that in general, the Cartesian parametrization is more robust and more numerically efficient than the others. Copyright © 2016 John Wiley & Sons, Ltd.