The eventual outcome of localized deformation is ductile rupture and material separation. For this reason, the combination of shear strain localization and eventual rupture is called shear failure. This phenomenon occurs and plays an important role in many applications. For example, shear bands are observed in ballistic impact, explosive fragmentation, high speed machining, metal forming, grinding, interfacial friction, powder compaction, granular flow, and seismic events. The formation of shear bands is a self-feeding process.
Plastic dissipation generates heat which causes the material to soften as temperature increases.
The thermal softening causes the material to deform at higher strain rates, resulting in further dissipation, temperature increase and thermal softening. This catastrophic cycle does not occur uniformly in the material. The result is the formation of narrow and distinct bands of high rates of shear deformation and high temperature. An important outcome of this process is the decrease of the material's stress-carrying capability, leading to precipitous drop in stress in later stages of the process. If deformation is allowed to continue, the eventual result is the ductile rupture of the material and total separation through the center of the shear band.