Study On the Long Bone Failure Behaviors Under the Impactor Rigid-Contact by Experiment Analysis and Subject-Specific Simulation.

Du, Xianping; Jiang, Binhui; Zhang, Guanjun; Chou, Clifford; Bai, Zhonghao

The bending fracture behaviors of long bone have gained great attention due to the high bending fracture risk during traffic accidents, etc. For evaluating bone bending behavior, most of the previous studies use an impactor in 3-pints bending experiments while the impactor rigidity was never considered. In this work, using the porcine long bones, the 3-point bending tests were conducted to explore the bone fracture behaviors under the rigid impactor. The bone fracture dynamic process was recorded by high-speed photography and the fracture surface profile was observed by the scanning electron microscope (SEM). Based on the CT scanning, their cross-section properties were calculated by a homemade MATLAB script for correlating with their strengths. Also, a subject-specific finite element (FE) model was developed to identify the influence on simulation. Findings led to conclusions as follows: 1) The tension fracture came with fracture path deflection, which was caused by the bone indentation induced mesoscale crack-opening. Due to this damage before the whole bone fracture, a bone fracture moment correction was defined to compensate experimental data. 2) The plastic indentation caused the impact force fluctuation. 3) The bone failure moment is higher correlated with the inertial moment of the bone cross-section than the traditional cross-section area. 4) In the subject-specific simulation, the indentation caused compression fracture and a much lower failure force. To reject the element erosion on impact location during only validation was verified as a good option to solve this issue.