基于椭球曲面的超塑自由胀形力学解析  

Mechanical Analysis for Superplastic Free Bulging Based on Ellipsoidal Surface

作　　者：刘胜京[1] 徐永超[2] 姜波[1] 雷海龙[1] 陈福龙[1] 

机构地区：[1]中航工业北京航空制造工程研究所,北京100024 [2]哈尔滨工业大学金属精密热成形国防科技重点实验室,哈尔滨150001

出　　处：《机械工程学报》2014年第18期73-81,共9页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(51334006)

摘　　要：超塑自由胀形的真实轮廓为轴对称旋转曲面,球面假设条件下的力学解析不能真实反映实际胀形过程。基于超塑自由胀形轮廓型面为椭球曲面这一试验基础,从连续介质塑性力学的基本理论出发,结合几何方程、力学平衡方程及Hill各向异性材料的增量理论,对超塑自由胀形过程进行力学解析,提出超塑自由胀形对壁厚均匀性的自我调节作用。给出超塑自由胀形过程中不同位置的经向应力及环向应力,并进一步得出应力场、应变速率场及应变场分布。由广义速率敏感性指数的定义式,给出m值的解析式,并得到超塑自由胀形的最佳加载路径。超塑自由胀形椭球曲面假设得到试验验证,椭圆函数拟合度高达0.996以上。The real profile of superplastic free bulging is axisymmetric rotating surface, and therefore the theory of spherical assumption can not reflect the actual superplastic free bulging process. Experimental results show that the shape of superplastic free bulging is ellipsoidal surface. Starting from the fundamental theory of plastic mechanics for continuous media, combined with the geometric equation, mechanical equilibrium equation and the anisotropic incremental theory of Hill, the mechanics analysis for superplastic free bulging process based on the assumption of ellipsoidal surface is accomplished. The self regulation on thickness uniformity is presented. The radial and tangential stress at different positions for free bulging is given, and then the spatial distribution of the stress, strain and strain rate fields is established. The analytical formula of the m value is given by utilizing its definition, and the optimal loading path of the superplastic free bulging is got. Ellipsoidal surface hypothesis is verified by experiment, and elliptic function fits up to more than 0.996.

关 键 词：超塑自由胀形 力学解析 椭球曲面 应变速率敏感性指数 

分 类 号：TG301[金属学及工艺—金属压力加工]