钛合金颅骨修复体的多点成形数值模拟

Numerical simulation on process of multi-point forming for titanium alloy cranial prosthesis

采用动态显式有限元软件,针对钛合金网板与压力机基本体直接接触、在基本体和钛合金网板之间放置聚氨酯弹性垫、在基本体和钛合金网板之间放置聚氨酯弹性垫和钢质垫板并使用压边圈3种不同的成形工艺进行数值模拟研究。模拟结果表明:采用前两种成形工艺得到的钛合金颅骨修复体表面出现压痕或起皱缺陷,采用在基本体和钛合金网板之间放置聚氨酯弹性垫和钢质垫板并使用压边圈这种成形工艺时,可以抑制压痕和起皱的产生,获得良好的成形效果。实验验证结果表明,应用多点成形技术,运用合理的成形工艺可以成形合格形状的钛合金颅骨修复体。

The following three forming technology modes were simulated by an explicit finite element analysis software： ①the titanium alloy retiary sheet is contacted with the press punch directly, ②the titanium alloy retiary sheet is sandwiched by polyurethane elastic cushions and contacted with the press punch indirectly, ③the titanium alloy retiary sheet is sandwiched by steel paddings and contacted with polyurethane elastic cushions and the press punch indirectly with the blank-holder device. Numerical simulation results showed that dimples and wrinkles occured on the surface of the titanium alloy cranial prosthesis in the first two forming technology modes. These two defects were suppressed when polyurethane elastic cushions and steel paddings were used between the titanium alloy retiary sheet and the press punch with the blank-holder device in the forming technology mode, and the 3D curved surface of prosthesis with good quality can be acquired. The experimental results showed that the titanium alloy cranial prosthesis can be eligibly shaped with the multipoint forming technology under the appropriate forming process.