Quantitative Visualization of Human Cortical Bone Mechanical Response: Studies on the Anisotropic Compressive Response and Fracture Behavior as a Function of Loading Rate

Blast and impact events regularly cause damage to human tissues. Efforts to improve protective gear are made through numerical simulation of these events where human tissues are exposed to high-rate loading conditions. Accurate simulation results can only be obtained if constitutive models are used that are based on precisely carried out experimental studies. Experimental studies on bone are challenging because of the relatively brittle nature of bone as well as the importance of the bone being in a hydrated state prior to experiments to avoid changing the mechanical properties. Past studies have utilized strain gages which require a period of drying time to bond strain gages to the surface of the bone. In this study, rate dependent fracture and compressive responses of wet human femur bone are investigated with in situ quantitative visualization. The fracture properties of cortical bone are studied transverse to the longitudinal axis of the bone up to high stress intensity factor rates, and the rate dependent compressive response is investigated in both longitudinal and transverse directions. The rate dependent nature of the fracture response, and the compressive behavior of human cortical bone over a range of rates from 0.001–1000 s-1 is discussed with the aid of quantitative visualization.