Application of ANSYS to the stress relaxation of articular cartilage in unconfined compression

The purpose of this paper is to establish a poroelastic model of cartilage for stress relaxation using the new elements in ANSYS version 12. Articular cartilage was modeled as a fluid-saturated solid because of its high water content and biphasic property. The biphasic theory for cartilage, which is capable of investigating the essential mechanical features of articular cartilage, was developed by Mow et al. (1980). In order to calibrate the material properties of the tissue-engineered cartilage, which is now emerging as a potential alternative treatment of osteoarthritis, the capacity of commercial software for modeling the cartilage needs to be verified. The aim of this research is to evaluate the porous elements available in ANSYS software and to promote the expanded application of the finite element method for analyzing soft tissues. By creating cartilage models using the fluid-solid coupling finite element analysis of porous media, ANSYS has been used in this paper to demonstrate the unconfined compressive behaviors of articular cartilage during stress relaxation. Furthermore, the validation of the fluid-solid coupling finite element model by ANSYS software ensures that the results of the present study are consistent with the analytical results of the linear Kuei, Lai, and Mow (KLM) biphasic theory.