形状记忆合金梁式管接头密封性能数值研究

针对一种阴接头密封梁具有椭圆弧凹槽的形状记忆合金梁式管接头，利用ABAQUS软件建立考虑管内流体压力和温度的弹塑性有限元热力耦合模型，数值模拟得到阴、阳接头间的接触带宽和接触应力分布。基于逾渗理论与微观粗糙密封界面有限元接触分析，计算得到形状记忆合金材料密封界面泄漏概率为零的临界接触应力。结合第一道密封的接触应力分布，以S指数作为形状记忆合金梁式管接头密封性能的评价指标，数值模拟了预紧力、管内流体压力和温度对形状记忆合金梁式管接头密封性能影响。结果表明：在装配拧紧力矩范围内形状记忆合金梁式管接头密封性能随着预紧力增大而增强；密封性能随着管内流体压力的升高会提高，具有良好的自封性；在-50～200℃的管内流体温度范围内密封性能基本稳定，满足密封要求。数值分析表明在相同工作条件下形状记忆合金梁式管接头相比于不锈钢和钛合金梁式管接头具有更优的密封性能。

Numerical study on the sealing performance of shape memory alloy beam seal

In view of a shape memory alloy beam seal with elliptical arc groove in the female connector, the elastoplastic finite element thermodynamic coupling model considering the fluid pressure and temperature in the pipe was established by using ABAQUS software. The contact bandwidth and contact stress distribution between the female and male connectors were obtained by numerical simulation. Based on percolation theory and finite element contact analysis of micro rough sealing interface, the critical contact stress with zero leakage probability of shape memory alloy sealing interface was calculated. Combined with the contact stress distribution on the primary seal, S index was used as the evaluation criterion of the sealing performance of shape memory alloy beam seal. The effects of preload, fluid pressure and temperature on the sealing performance of shape memory alloy beam seal were numerically simulated. The results showed that within the range of assembly tightening torque, the sealing performance increased with the increase of preload; the sealing performance increased with the increase of fluid pressure in the pipe, indicating that it had good self-sealing feature; the sealing performance was basically stable within the fluid temperature range of ?50— 200 ℃, which could meet the sealing requirements. Numerical analysis showed that shape memory alloy beam seal had better sealing performance than stainless steel and titanium alloy beam seal under the same working conditions.