铝锂合金压铆壁板残余应力与疲劳性能分析

自动压铆是航空制造工业中的重要装配技术,压铆过程结束后铆孔周围产生的残余应力的分布形式与压铆结构的疲劳性能息息相关。本文使用ABAQUS软件建立了2060-T8铝锂合金壁板压铆过程的有限元模型,通过有限元分析发现了压铆后铆孔壁面上的残余应力由靠近镦头处到靠近钉头处逐渐降低的分布规律。随着压铆力由28.5kN增大至46kN,铆钉材料为2117-T4的压铆壁板孔壁平均残余应力提高33%,残余应力沿壁板厚度上分布的均匀度提升180%；铆钉材料为7050-T73的压铆壁板孔壁平均残余应力提高58%,残余应力沿壁板厚度上分布的均匀度提升184%。疲劳裂纹萌生于铆接下板孔壁附近,随着压铆力由32.5kN增大至42kN,铆钉材料为2117-T4的压铆壁板疲劳寿命提升了31%~80%,铆钉材料为7050-T73的压铆壁板疲劳寿命提升6%~161%。相比于铆钉材料为7050-T73的压铆壁板,相同工艺条件下铆钉材料为2117-T4的压铆壁板疲劳寿命提升12%~44%。

Analysis of Residual Stress and Fatigue Performance of Al-Li Alloy Riveted Panel

Automatic riveting is an important assembly technology in the aviation manufacturing industry. The distribution of residual stress around the rivet hole after the riveting process is closely related to the fatigue performance of the riveting structure. In this paper, ABAQUS software was used to establish the finite element model of the press riveting process of the 2060-T8 Al-Li alloy plate. It was found that the residual stress on the wall of the rivet hole after the riveting process gradually decreased from the place close to the rivet head to the place close to the rivet head. With the pressure riveting force increasing from 28.5kN to 46kN, the average residual stress of the hole wall of the riveted plate with the rivet material of 2117-T4 increases by 33%, and the uniformity of the residual stress distribution along the thickness of the wall plate increases by 180%. The average residual stress of the hole wall of the riveted plate with 7050-T73 rivet material is increased by 58%, and the uniformity of the residual stress distribution along the thickness of the wall plate is increased by 184%. The fatigue crack originated near the hole wall of the riveted lower plate. With the increase of the riveting force from 32.5kN to 42kN, the fatigue life of the riveted plate with the rivet material of 2117-T4 increased by 31%~80%, and the fatigue life of the riveted plate with the rivet material of 7050-T73 increased by 6%~161%. Compared with the riveted plate with rivet material of 7050-T73, the fatigue life of the riveted plate with rivet material of 2117-T4 under the same process conditions is increased by 12%~44%.