The strain rate dependent mechanical properties and modelling of bovine cortical bone in compression

Conventional Hopkinson bar experiments resulted in a specimen strain rate that decreases beyond reaching a maximum value at the rise time. The variation in dynamic strain rate was rectified by shaping the Hopkinson bar input pulse with a reusable, conical striker bar. The hypothesis investigated was that a varying strain rate history could result in the measurement of a smeared response for materials with significant strain rate sensitivity. Results indicate that nonuniform, dynamic strain rates result in irregular stress-strain curves; however the stress-strain responses comprise the same corridor as the constant strain rate responses. Bovine cortical bone exhibits significant strain rate sensitivity, with distinct corridors of quasi-static and dynamic stress-strain response. Fracture occurs at a higher stress for both increasing strain rate and bone density. A microstructural investigation indicated that longitudinal compression of bovine bone leads to the formation of shear bands and that fracture depends on the orientation of the vascular porosity.

Grantor dc:publisher.institution

Department of Mechanical Engineering

Year dc:date.issued

2008

Author dc:creator

• Van der Westhuizen, Anriëtte

Advisor dc:contributor.advisor

• Nurick, Gerald N

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/5459

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/5459