A combination of continuum damage mechanics and the finite element method to analyze acrylic bone cement cracking around implants

We present a method to simulate acrylic bone cement damage accumulation around implants. The method combines the finite element method (FEM) with the theory of continuum damage mechanics (CDM). Damage was considered a tensorial variable, resulting in anisotropic material behavior when the material was damaged. The method was applied to an axi-symmetric structure, consisting of a taper pushed in a cement mantle. Varying the taper/cement interface conditions revealed that these had considerable effects on the damage process. Not only the mechanical endurance of the structure changed, but also the way in which damage progressed was affected. Two mesh densities were considered, to study the effects of mesh refinement. It was concluded that, although further research is required to obtain more realistic survival times, the method can be used on a comparative, qualitative basis. It predicts, pre-clinically, sites where cement damage is initiated, how this process progresses, and the effects of design parameters of implants on the mechanical endurance of the structure

Biomechanics of artificial joints : the hip

No abstrac

Biomechanics of artificial joints : the hip

No abstrac

A combination of continuum damage mechanics and the finite element method to analyze acrylic bone cement cracking around implants

We present a method to simulate acrylic bone cement damage accumulation around implants. The method combines the finite element method (FEM) with the theory of continuum damage mechanics (CDM). Damage was considered a tensorial variable, resulting in anisotropic material behavior when the material was damaged. The method was applied to an axi-symmetric structure, consisting of a taper pushed in a cement mantle. Varying the taper/cement interface conditions revealed that these had considerable effects on the damage process. Not only the mechanical endurance of the structure changed, but also the way in which damage progressed was affected. Two mesh densities were considered, to study the effects of mesh refinement. It was concluded that, although further research is required to obtain more realistic survival times, the method can be used on a comparative, qualitative basis. It predicts, pre-clinically, sites where cement damage is initiated, how this process progresses, and the effects of design parameters of implants on the mechanical endurance of the structure

Pre-clinical testing of hip prosthetic designs : a comparison of finite element calculations and laboratory tests

To investigate the accuracy of finite element (FE) models for pre-clinical testing of unbonded hip prostheses, relative to aspects of load transfer and micromobility, two previously published laboratory experiments were simulated, using three-dimensional FE models. It was found for the load-transfer analyses that the experiment and the FE study revealed results that were very similar. The trends in the mobility experiments were also reproduced in the FE simulations, although quantitative differences were found. It is concluded that FE analysis can effectively be used for design evaluation of hip prostheses before prototypes are mad