Strain rate dependent poroelastic behavior of bovine vertebral trabecular bone

It is widely accepted that the pressure variation of interstitial fluid is one of the most important factors in bone physiology. In order to understan d the role of interstitial fluid on porous bony structure, a consideration for the biomechanical interactions between fluid and solid constituents wit hin bone is required. In this study, a poroelastic theory was applied to in vestigate the elastic behavior of calf vertebral trabecular bone composed o f the porous solid trabeculae and the viscous bone marrow. The poroelastic behavior of trabecular bone in a uniaxial stress condition was simulated us ing a commercial finite difference analysis software (FLAC, Itasca Consulti ng Group, USA), and tested for 5 different strain rates, i.e., 0.001, 0. 01 , 0.1, and 10 per second. The material properties of the calf vertebral tra becular bone were utilized from the previous experimental study. Two asympt otic poroelastic responses, the drained and undrained deformations. were pr edicted. From the predicted results for the simulated five strain rates. it was found that the pore pressure generation has a linearly increasing beha vior when the strain rate is the highest at 10 per second, otherwise it sho wed a nonlinear behavior. The pore pressure generation with respect to the strain was found to be increased as the strain rate increased. The elastic moduli predicted at each strain were 208.3, 212.2, 337.6, 593. 1. and 602.2 MPa, respectively. Based on the results of the present study, it was sugge sted that the calf vertebral trabecular bone could be modeled as a poroelas tic material and its strain rate dependent material behavior could be predi cted.