基于响应面的TA1钛合金内螺纹管芯轴结构参数优化

Optimization on structural parameters of mandrel for TA1 titanium alloy internal thread pipe based on response surface

为了得到芯轴最优的结构参数,采用响应面法以螺纹长度L、螺纹升角φ_(1)及芯轴迎角φ_(2)为设计变量,以螺纹管料头齿部的速度相对差值VRD_(1)与管壁的速度相对差值VRD_(2)及挤压成形最大载荷F为优化目标参数,建立了多响应回归模型,采用粒子群算法对已建立的多响应回归模型进行全局寻优,最终得到内螺纹管芯轴的最优参数为:螺纹长度L=11 mm、螺纹升角φ_(1)=30°以及芯轴迎角φ_(2)=96°。优化后的VRD_(1)减小了50.38%,VRD_(2)减小了44.81%,F值减小了5.10%,采用最优芯轴结构参数进行模具加工并进行挤压试验,得到了质量合格的TA1钛合金内螺纹管。结果表明,采用响应面法优化后的芯轴结构可以提高挤压过程中金属的流动性,减小模具的最大成形载荷,提高内螺纹管的成形质量。

In order to obtain the optimal structural parameters of mandrel,taking thread length L,thread lift angleφ_(1) and attack angle of mandrelφ_(2) as the design variables,and taking velocity relative difference VRD_(1) of material head tooth in thread pipe,velocity relative difference VRD_(2) of pipe wall and maximum load F of extrusion forming as the optimization target parameters,the multi-response regression model was established.Then,the established multi-response regression model was globally optimized by particle swarm algorithm,and the optimal parameters of internal thread pipe mandrel were finally obtained as the thread length L=11 mm,the thread lift angleφ_(1)=30°,and the attack angle of mandrelφ_(2)=96°.Furthermore,after optimization,VRD_(1) was reduced by 50.38%,VRD_(2) was reduced by 44.81%,and F value was decreased by 5.10%.Finally,the mold was processed by the optimal structure parameters of mandrel,and the extrusion test was conducted to obtain the qualified TA1 titanium alloy internal thread pipe.The results show that the mandrel structure optimized by the response surface method can improve the fluidity of metal in the extrusion process,reduce the maximum forming load of mold,and improve the forming quality of internal thread pipe.