时效应力松弛校形原理及其在蒙皮制造中的应用

时效应力松弛校形和成形方法已成功地用于制造飞机铝合金蒙皮壁板,具有很多优点。本文论述该方法的原理、应用和模拟试验结果。通过2024和LY12铝合金板件的单曲度与双曲度弯曲试验,研究了校形效果随温度、时间和预变形等的变化规律。回弹和残余应力的测量结果表明,校形效率随温度和时间提高,在铝合金人工时效温度和时间范围内,一次约可消除回弹60％。剩余的尺寸偏差可通过在夹具上修出过弯量消除。

PRINCIPLE OF THE AGEING-STRESS RELAXATION SIZING AND ITS APPLICATION TO THE SKIN FABRICATION

The ageing-stress relaxation sizing and forming processes have been successfully used to form complex skin panels to typical aircraft tolerances with many advantages compared to other methods.This paper discusses the principle and simulation experiments.The relationships among the sizing ability with sizing temperature,time and predeformation are studied by means of the bending tests with 2024 and LY12 aluminium alloy plates.The measurements of contour and residual stresses of specimens before and after the sizing process show that the sizing effectiveness increases with relaxation temperature and time.In the allowable range of artificial ageing temperature and time of the aluminium alloys,the bending spring-back can be removed by 60%.The remaining discrepancy can be corrected by applying over-curving to the formed part.With this process the sizing effectiveness of annealed aluminium alloys is better than that of hardening alloys.