组合式扁挤压筒结构优化设计.pdf

组合式扁挤压筒的结构优化设计摘要扁挤压筒是挤压大型整体铝合金壁板的重要工具。由于扁挤压筒要在高温、高压、,容易开裂,影响了使用寿命。因此,为了提高扁挤压筒的强度,延长其使用寿命,需对组合式扁挤压简进行应力分析和结构优化设计,以充分发挥模具材料的潜力,确保挤压筒的最佳工作性能。本文综合运用数值模拟、理论解析等方法,建立扁挤压筒受非均布内压力、预紧力和热载荷联合作用下的分析模型并求解,得到各种受载条件下的应力分布状况:为改善挤压过程中金属流动状况,通过引入流函数法和保角映射方法, 建立了扁挤压筒型腔到模口之间过渡曲面的流线方程,完成了过渡曲面的数学描述。结合有限元法、神经网络和遗传算法对等过盈量设计下的三层组合式扁挤压简结构尺寸进行了优化设计:在此基础上,引入了变过盈量设计理论,综合考虑了挤压筒的最佳工作性能和内腔的尺寸精度,建立了变过盈量下三层组合式扁挤压筒结构的多目标优化模型,实现了扁挤压筒的多目标优化设计,经过分析、比较及论证,得出了一套可行的组合式扁挤压筒的结构优化方案。本文的研究成果对于完善壁板挤压模具设计理论具有实际指导意义。关键词:扁挤压筒过渡曲面BP神经网络遗传算法多目标优化 Structural Optimum Design bined Flat Extrusion Container Abstract Flatextrusion container isthemost important toolforextruding largeintegral aluminum ofworking under the severe conditions ofhigh temperature,high pressure andhigh friction,the sLrcss distribution offlatextrusion container isveryuneven and easy order toimprove thestrength and prolong theworking life ofthe flat extrusion container,the stress analysis and structural optimum design ale isadvantageous tomake full use ofthe material potential of the mould and make sure of getting itsbest working performance. Wjtll numerical simulation and theoreticalanalysis,the thermal·stress coupling analysis bined flatextrusion container under thenon-uniformly distributed pressure isrealized,and thestress distributions ofvarious loading are improving theflow status ofextrusion metal,the mathematic function of订ansffionaI surface between theoutletofflatextrusion container and theinletof dieisestablished withthetheories offlow function andconformal mapping. bining themethods ofFinite-element method,works(NN)and icalgorithms(GA),the structural sizesofthree—bined flatextrusion container under theuniform shrinkage design tothis,and considering thestrengeth offlatextrusion containerand dimensional accuracy ofirmer layercavity,themulti—objective structuraloptimization ofthree—bined flat extrusion container under thenon—uniform shrinkag