(1. 南昌航空大學(xué) 航空制造工程學(xué)院，南昌 330063；
2. 南京航空航天大學(xué) 機(jī)電學(xué)院，南京 210016)
摘 要: 引入離散化思想將鋁厚板劃分為若干層，依據(jù)淬火殘余應(yīng)力定義各層的等效塑性應(yīng)變；通過各層材料應(yīng)力-應(yīng)變曲線的線性近似后，根據(jù)等效塑性應(yīng)變推導(dǎo)出誤差不超過2%的屈服極限分布模型。此外，根據(jù)彈性模量隨塑性變形進(jìn)展而不斷變化的實(shí)驗(yàn)數(shù)據(jù)，擬合出彈性模量的變化曲線。以淬火7075鋁厚板的預(yù)拉伸為例，考慮淬火所引起的屈服極限與彈性模量的非均勻性，分別進(jìn)行預(yù)拉伸率為1.8%、2.2%和2.5%的殘余應(yīng)力有限元仿真，無論是分布曲線還是應(yīng)力的大小，殘余應(yīng)力仿真值與實(shí)驗(yàn)測量值均比較吻合，分布曲線拐點(diǎn)處殘余應(yīng)力的平均誤差僅為13.5%。
關(guān)鍵字: 鋁合金厚板；淬火；預(yù)拉伸；材料非均勻性；殘余應(yīng)力
（1. School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China;
2. College of Mechanical and Electrical Engineering,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China）
Abstract:The discretization method was employed to separate the aluminum alloy thick plate into several levels. The equivalent plastic strain was defined for each level according to the residual stress during quenching. With the linear approximation of the stress-strain curve, the yield strength model with less than 2% difference was formulated as a function of the equivalent plastic strain. Moreover, the curve of elasticity modulus according to the variation of elasticity modulus with plastic deformation was fitted. Finally, by considering the non-uniformity of yield strength as well as elasticity modulus, the pre-stretching of the 7075 quenched aluminum alloy thick plate was simulated for the residual stresses when the pre-stretching rates are 1.8%, 2.2% and 2.5%, respectively. Whether the distribution curve or the stress magnitude, the simulated residual stresses obtained by the proposed method are in good agreement with the experimental data. The average error of the simulated residual stresses at the inflection points of the distribution curve is only 13.5%.
Key words: aluminum alloy thick plate; quenching; pre-stretching; material non-uniformity; residual stress
