摘要
对板料成形中圆筒形件拉深的破裂失稳及产生破裂失稳的临界压边力进行研究。由于凸、凹模圆角及其间隙的存在,圆筒形件拉深的简壁区实际为凸、凹模圆角之间的公切线部分。根据Mises-Hill屈服函数及Tresca准则求出凸缘变形区、凹模圆角区和筒壁区的应力分布,得到危险断面处的应力表达式,从而求出不产生破裂失稳的临界压边力的解析表达式,并进一步分析获得拉深比、硬化指数、厚向异性系数、摩擦因数以及径向推力等因素对临界压边力的影响规律。采用液压压边与周缘加径向推力的拉深模具对08A(?)板料进行拉深试验,试验结果与理论计算结果具有很好的一致性。
The rupture instability and its critical blank-holder force of cylindrical deep drawing in sheet forming process are theoretically and experimentally investigated. The wall of cup drawing is the common tangent region due to the punch, die profile and the clearance of them. The stress distribution of flange, die profile and wall segment are established by Mises-Hill yield function and Tresca criterion. The stress function of the crucial surface occurring rupture instability is constructed. Furthermore, the critical blank-holder force occurs rupture instability is obtained. The effects of various parameters including draw ratio, strain hardening, normal anisotropy, friction coefficient and radial pushing force on rupture instability are showed, analyzed and discussed. During the experiment using 08A1 steel sheet as workpieces hydraulic pressure is applied on the blank as blank-holder force and the periphery of the cup flange as radial pushing force. Good agreement is found between the theoretical calculations and the experimental results.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2007年第3期154-159,共6页
Journal of Mechanical Engineering
基金
西安交通大学博士论文基金(DFXJTU2005-11)
国家自然科学基金(50375117)资助项目。
关键词
板料成形
拉深
失稳
临界压边力
破裂
Sheet forming
Deep drawing
Instability
Critical blank-holder force
Rupture
