Analysis on shear band development under large strain torsion of amorphous glassy polymers

Unlike the shear band development of metals generally regarded as the precursor to failure, the shear banding process in amorphous glassy polymers is known to influence both the strengthening and fracturing behaviors. Complementary to the previous experimental work in the literature on the shear band development under torsion under limited cases, the finite element (FE) analysis has been conducted to investigate the general shear banding behaviors in terms of the initiation and propagation in more detail. The FE model has been established by incorporating the Boyce-Parks-Argon (BPA) constitutive model with the full-network modification via a user material subroutine in ABAQUS. A series of nondimensional quantities were used to discuss the mesh sensitivity and the effects of predefined imperfections, specimen geometry, and torsion mode. Besides, by altering the extents of the intrinsic material softening and the strain hardening, the shear banding behaviors of typical materials under typical temperature and strain rate conditions are equivalently investigated. The validity of the simulation has been qualitatively validated by directly comparing with the experimental results from the literature.