Ti55钛合金整体壁板电脉冲辅助压弯成形失稳研究

Study on Instability of Ti55 Titanium Alloy Monolithic Panel by Electric Pulse Assisted Bending

摘要:

高温钛合金网格筋壁板相较于传统的铝合金筋壁板结构效率更高,但是常温下钛合金整体壁板难以成形。利用电流电致塑性效应和焦耳热效应能有效降低成形载荷、提高成形极限,并且能有效避免钛合金加热氧化严重的问题。本文建立了Ti55整体壁板电脉冲辅助压弯成形的电-热-力耦合有限元模型,并对不同成形工艺参数和壁板几何参数进行模拟,结果表明在壁板两端施加8A/mm_²电流密度时,压弯成形温度区间比较合适。整体壁板随着筋条高度的增加,失稳屈曲程度越来越大,筋条失稳时所需的临界载荷越小,筋条的稳定性越差。腹板厚度主要是影响筋条的温度从而影响筋条的失稳情况。整体壁板横向筋条间距增大,筋条稳定性越差,筋条失稳屈曲也越严重。

关键词:整体壁板;电辅助压弯;有限元模型;筋条失稳

Abstract:

The high-temperature titanium alloy mesh rib panel is more efficient than the traditional aluminum alloy rib wall plate, but the titanium alloy monolithic wall plate is difficult to form at room temperature. The use of current electroplasticity effect and Joule heat effect can effectively reduce the forming load and increase the forming limit, and can effectively avoid the problem of serious oxidation oxidation of titanium alloy.In this paper, the electric-thermo-mechanical coupled finite element model of electric pulse assisted bending forming of Ti55 integral panel is established, and different forming process parameters and panel geometric parameters are simulated. The results show that 8A/mm2 current is applied at both ends of the wall plate For density, the temperature range of press forming is more suitable. As the height of the ribs increases, the degree of instability buckling becomes larger and larger. The smaller the critical load required when the ribs are unstable, the worse the stability of the ribs. The thickness of the web mainly affects the temperature of the ribs and thus the instability of the ribs. The greater the spacing of the transverse ribs of the overall wall panel, the worse the stability of the ribs and the more serious the buckling of the buckling.

Key words:integral panel; electric assisted bending; finite element model; rib instability