Deformation instabilities in extensional plastic flow of polymers

2 Deformation instabilities in extensional plastic flow of polymers 

In this chapter the subject of primary interest is the plastic-flow instabilities occurring in extensional deformation of fibers or bars of solid polymers with an inelastic constitutive response as discussed in Chapters 7-9. There, localization in shear was featured prominently both in unit plastic events in the form of shear transformations and also in the form of more homogenized processes resulting in macro shear bands. The discussion here concentrates on complementary instabilities occurring in extensional plastic fiow of fibers or bars of solid polymers from a 

---