钛合金筋板类构件局部加载成形有限元仿真分析中的摩擦及其影响

局部加载等温成形为大型钛合金筋板类构件省力、高性能成形制造提供了有效的途径。然而其成形过程复杂,材料参数、几何参数、工艺参数高度耦合作用,精确预测困难。有限元仿真为此类复杂成形问题的分析和优化提供了有力的工具。而摩擦模型和摩擦条件是数值模拟的重要边界条件之一,影响到预测结果的精度及可靠性。本文着重分析了库伦摩擦模型、剪切摩擦模型、库伦-剪切摩擦模型、库伦-粘着摩擦模型以及摩擦大小对筋板类构件局部加载成形仿真分析结果的影响。研究结果表明:剪切摩擦模型适用于局部加载成形过程的建模仿真;确定精确的摩擦条件可降低载荷预测误差15%以上;主动调控局部区域摩擦条件可改善局部加载成形过程的充填、减少缺陷。

Friction and Influence in FEM Simulation of Local Loading Process for Titanium Alloy Rib-Web Component

Isothermal local loading process provides an efficient approach to manufacture large-sized titanium-alloy ribweb component with saving force and high performance.However,the forming process is complex,and the material parameter,geometric parameter and processing parameter have a stronger coupling action in the forming processing,so the accurate prediction about the process is difficult.The finite element simulation provides a powerful approach for analyzing and optimizing this complex forming process.The friction model and friction condition are one of the key boundary conditions in numerical simulation,which play an important role in accuracy and reliability of predicted results.In this paper,the influences of the friction models such as Coulomb friction model,shear friction model,Coulomb-shear friction model and Coulomb-sticking friction model,and the magnitude of friction on the simulation results for local loading process of rib-web component have been analyzed.The results in the present study indicate that:The shear friction model is suitable for the modeling and simulation of local loading process;Accurate friction condition can decrease predicted error of forming loadby more than 15％;Active controlling the friction in local zone will improve the cavity filling and reduce the forming defect.