基于ABAQUS及疲劳试验的烧结股骨柄设计研究

Design of sintered femoral stem based on ABAQUS and fatigue test

目的确保精锻Ti-6Al-4V钛合金烧结股骨柄柄体能达到植入后支撑人体体重及运动循环载荷的要求。方法通过对Worst Case下的烧结股骨柄进行数值模拟,设计3种烧结涂层区域不同(不同的应力规避区)的股骨柄,并对其分别进行疲劳试验。结果通过数值模拟,Worst Case下的烧结股骨柄的最大主应力为432.8 MPa;方案一中股骨柄外侧烧结涂层至股骨柄肩部的距离为47 mm(规避处的应力值为309.493 MPa),疲劳试验结果为6组全部断裂,循环载荷次数均为2.3×10^6次上下;方案二中股骨柄外侧烧结涂层至股骨柄肩部的距离为44 mm(规避处的应力值为277.673 MPa),疲劳试验结果为2组断裂,循环载荷次数均为4.1×10^6次上下,其余4组通过5×10^6次循环试验;方案三中股骨柄外侧烧结涂层至股骨柄肩部的距离为41 mm(规避处的应力值为240.755 MPa),6组均通过5×106次循环试验,股骨球头垂直偏移量最大的一组的偏移值为1.55 mm。结论方案三的精锻Ti-6Al-4V钛合金烧结股骨柄在植入后能达到支撑人体体重和运动时循环载荷的要求。

Objective Ensure that the precision forged Ti-6Al-4V titanium alloy sintered femoral stem can support the body weight and the cyclic load of motion after implantation. Methods The femoral stems of three different sintered coating regions (different stress avoidance zones) are designed by numerical simulation of the sintered femoral stem under Worst Case, and fatigue tests are carried out separately. Results Through numerical simulation, the maximum principal stress of the sintered femoral stem under Worst Case is 432.8 MPa;in the first solution, the distance from the outer side of the femoral stem to the shoulder of the femoral stem is 47 mm (the stress value at the avoidance point is 309.493 MPa), the fatigue test results showed that all the six groups are fractured, and the number of cyclic load are 2.3×10^6 times;in the second solution, the distance from the outer side of the femoral stem to the shoulder of the femoral stem is 44 mm (the stress value at the avoidance point is 277.673 MPa), and the fatigue test results of two groups are fractured, the number of cyclic load are 4.1×10^6 times, and the other four groups passed the 5×10^6 cycle test;in the third solution, the distance from the outer side of the femoral stem to the shoulder of the femoral stem is 41 mm (the stress at the avoidance point is 240.755 MPa), and the six groups all passed the 5×10^6 cycle test, and the offset of the group with the largest vertical offset of the femoral ball is 1.55 mm. Conclusion The precision forged Ti-6Al-4V titanium alloy sintered femoral stem of the third solution can meet the requirements of supporting the body weight and the cyclic load during exercise after implantation.