No abstract

A high-modulus polymer, polysulfone, was evaluated as a porous bone implant material. The bone ingrowth into canine cortical pellets of sintered polysulfone particles was assessed by microradiography and histology. The shear strength of the porous polysulfone-bone interface was determined by push-out and pull-out tests of cortical and trochanteric implants, respectively. Results indicated that the bone ingrowth into porous polysulfone specimens proceeded in such a fashion as to mimic the normal repair at the site. Mechanical testing of cortical and cancellous implants revealed that the interfacial shear strength of the porous polysulfone-bone composite was similar to that achieved using porous metals.

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Initial-yield results on SAE 1017 steel are presented for: four different specimens under combined axial load and twisting moment for servo controlled loading; and six different specimens under various combinations of servo controlled axial strain and shear strain. Subsequent yield curves determined by small strain offset multiple probes on a given specimen are presented covering all four quadrants of axial stress-shear stress space. The resulting families of subsequent yield curves allows conclusions to be drawn concerning the effects of plastic strain and strain aging. All curves were found to be convex and normality of the plastic strain increment vector was obeyed. The response to plastic straining allowed discussion of corner formation, translation, rotation, Bauschinger and cross effects of subsequent yield curves and formation of a limit curve. A comparison is made between the experiments and the Prager kinematic hardening model and the Ziegler modification.