An analysis of Bauschinger parameters in torsion

Hysteretic pinching of human secondary osteons subjected to torsion

“…Pinching is due to (i) ultrastructural kinematic hardening, called the Bauschinger effect (Lee, 1989;Yaman et al, 1990;Zhao and Lee, 2002); (ii) the size of the differential angles between the fiber/rebar direction and the principal stresses in reinforced materials (Mansour and Hsu, 2005); and (iii) the local prying effect in a connection or joint (Piraprez, 1993). Analogously, the source of pinching here is ascribed to the main ultra-structural components, collagen fibrils and apatite crystallites, and their connections.…”

“…Indeed, the Bauschinger effect was originally defined for metals under tension/compression loading. Subsequently, the definition was broadened to apply to other loading modes as a change (as softening or hardening) of material upon downloading and reloading in a direction opposite to the original loading direction, including torsion (Yaman et al, 1990;Zhao and Lee, 2002). Further, such weakening would cause prying effects of apatite crystals at the nonmineralized collagen interface.…”