(山東理工大學(xué) 機(jī)械工程學(xué)院，淄博 255000)
摘 要: 對板材理想自彎曲擠出過程的平面應(yīng)力分析得到出口速度分布與彎曲曲率半徑的關(guān)系，并提出一種鋁合金板材自彎曲擠壓新工藝，通過設(shè)計(jì)異形導(dǎo)流腔結(jié)構(gòu)，使模腔內(nèi)金屬產(chǎn)生不均勻流動(dòng)，從而直接擠出彎曲型材；采用有限元模擬，分析了板材擠壓過程的自彎曲變形機(jī)理、金屬流動(dòng)特點(diǎn)以及殘余應(yīng)變的分布；通過選取型腔結(jié)構(gòu)因子與擠壓速度為設(shè)計(jì)變量，采用拉丁超立方抽樣方法結(jié)合模擬計(jì)算，建立了擠出型材彎曲曲率半徑的響應(yīng)面預(yù)測模型，在指定彎曲半徑為1900 mm的條件下，建立附帶罰函數(shù)的目標(biāo)函數(shù)優(yōu)化模型，利用粒子群算法得到最優(yōu)模腔結(jié)構(gòu)與工藝參數(shù)，并進(jìn)行擠壓試模實(shí)驗(yàn)。實(shí)驗(yàn)結(jié)果顯示，板材擠出時(shí)彎弧穩(wěn)定，測得曲率半徑為2071 mm，彎曲板材內(nèi)外側(cè)晶粒大小均勻。
關(guān)鍵字: 鋁合金；彎曲板材；自彎曲成形；關(guān)系推導(dǎo)；機(jī)理分析；優(yōu)化設(shè)計(jì)
（School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China）
Abstract:Based on the theory of continuum mechanics, the relationship between the exit velocity distribution and the radius of curvature of the plate during the ideal self-bending process is obtained. A new process for the self-bending extrusion of aluminum alloy plates was proposed. By designing the structure of special-shaped guide cavity, the uneven flow of metal in the die cavity was produced, so the bent profile is directly extruded. By using numerical simulation, the self bending deformation mechanism, metal flow characteristics and distribution of residual strain in the process of sheet profile extrusion were analyzed. The response surface prediction model of each variable to the radius of curvature of extrusion self bending was established by using the Latin hypercube sampling method and the finite volume method. Under the condition of a specified bending radius of 1900 mm, an objective function optimization model with a penalty function was established. The algorithm obtains the optimal cavity structure and process parameters, and conducts trial experiments. The experimental results show that the self-bending sheet extrusion is stable, the measured radius of curvature is 2071 mm, the grain size inside and outside of the curved sheet is uniform.
Key words: aluminum alloy; bending sheet profile; self bending forming; relation derivation; mechanism analysis; optimal design
