FINITE ELEMENT STUDY OF A TROCHANTERIC GAMMA NAIL (TGN) FOR A TROCHANTERIC FRACTURE: VISUALIZATION OF THE 3-D STRESS DISTRIBUTION PATTERNS BY MEANS OF A MULTI-COLOURED 3DP MODEL

摘要

A three-dimensional finite element study of a trochanteric fracture fixation by means of a trochanteric Gamma nail (TGN) was investigated in this study. The analyses were performed under single-legged stance load boundary conditions to study the stress distribution in both the implant and the proximal femur. The average geometry of the Asian proximal femur was derived from computerized tomography scans and using reverse engineering techniques to create the average boundary surfaces. The influence of material properties (E-modulus) of implant, bone and contact conditions in the fracture zone was determined. We used the VRML format to transfer the finite element stress analysis results into the RP software. Multi-coloured 3DP models were made from the von Mises stress distribution patterns of both the implant and the proximal femur model using Z-Corp's Z406 3DP machine. The new technique of colour coded visualization allows for a full 3D visual interpretation of the stress distributions resulting from FE calculations. The application of RP for concept modeling as a design communication tool in the early stages of product design has been generally accepted. Multi-colour coded physical models of a prototype incorporating information such as stress distribution and deformation patterns from a finite element analysis are believed to be a very useful advanced design communication tool that goes beyond the conventional use of a concept model in the early design stages.