Effect of muscle on cortical bone layer by finite element modeling

Muscle is one of the important parts of the body as it made up from a bundle of fibrous tissue. The effects of fracture mechanisms of the bone are been studied related with the existing of muscle layer. In order to establish cortical bone with muscle layer, the structure of the base must be relevant and efficient. Therefore, finite element modeling method is an alternative way to study the effect of human fracture mechanisms with and without muscle layer. The aim of this study is to develop two dimensional (2D) model of human cortical bone and muscle layer in linear elastic fracture mechanics (LEFM) and elastic plastic fracture mechanics (EPFM) by using ANSYS APDL applied on three-point bending test. Other than that, Stress Intensity Factor (K) and Strain Energy Release Rate (J-Integral) were analyzed on both 2D models which are cortical bone layer and cortical bone with muscle layer. Two methods were used to evaluate the values of K which are Displacement Extrapolation Method (DEM) and Constrained Integration (CINT) method. The experimental values then been compared with two theoretical expressions for validation purposes. By referring to the values of error for K and J-Integral values in both methods, it is proved that by using CINT method, the model produced smaller error and higher efficiency. By comparing the two models, cortical bone with muscle layer resulted lower K and J-Integral values. It can be concluded that layer of muscle on the cortical bone gives an impact on the crack tip that allow the growth of the crack.