Abstract
The fatigue characteristics that simulated a bone plate having a hole were evaluated. And technique of fatigue duration of life evaluation was studied. A Ti-6Al-4V alloy and SUS316L steel were used for test materials. A specimen configuration is plate of thickness 2mm with both materials. And a penetration hole of a diameter of 2.5mm and 5.5mm, 7.5mm was emptied centrally. A stress concentration coefficient (Kt) is 2.5 and 2.2, 2.1 respectively. The fatigue test performed a uniaxial pulling fatigue test (stress ratio (R) = 0.1, frequency =10Hz, a sine wave). In addition, the examination went in atmosphere environment. A fatigue fracture was observed using SEM. In addition, by a electromagnetic field analysis (FEM), analyzed fracture stress of a hole bottom. And a fatigue fracture mechanism was considered by analyzing load distribution. Fatigue strength of a Ti-6Al-4V alloy is not associated with hole diameter, and fatigue strength is about the same. In other words it was confirmed that there was not influence by size of hole diameter. The fatigue test of SUS316L steel understood that was superior so that hole diameter was large. In addition, fatigue strength of fatigue limit (N_f=10^7 times) is superior so that hole diameter is large. It developed that this was maximum stress (σ max) and a difference of stress distribution.
