DEVELOPMENTS, MECHANICAL PROPERTY MEASUREMENTS AND STRENGTH EVALUATIONS OF THE WRIST BRACES FOR THE WRIST FRACTURE PATIENTS

In this paper, the wrist braces for the wrist fracture patients are developed. Geometry of the patient's wrist surface anatomy was digitalized and recorded by an optical 3D scanner. An expert software was developed to generate the brace model, on which several holes are distributed to increase the air permeability. Finally, the brace is fabricated by commercial FDM 3D printer. For ensuring the strength of the wrist brace, the tensile test and impact test were conducted to measure the elastic modulus, yielding strength and fracture strength. A finite element model was established to investigate the stresses and deformations when the wrist brace is subjected to a static load. The mechanical properties measured in the tensile tests are as input parameters in the model. The static analysis showed that, for four considered movements of the wrist, the maximum von-Mises stress is less than the yielding strength. An impact analysis was also conducted to simulate brace impacted by a moving rigid ball with a mass of 0.3768kg. The results showed that the deformation at the impact point remains in the elastic range when the impact speed is 3m/s. The finite element calculations give us rules to design the number of holes and the thickness of the brace.