扁挤压筒的挤压力及应力场的光弹性分析  

Photoelastic Analysis of Extruded Pressure and Stress Distribution in a Flat Extrusion Container

作　　者：王美芹[1] 许在文[1] 柳兆涛[1] 王炯华[1] 刘全坤[1] 

机构地区：[1]合肥工业大学土建学院,安徽合肥230009

出　　处：《实验力学》2004年第3期376-380,共5页Journal of Experimental Mechanics

基　　金：国家自然科学基金资助项目(50075022)

摘　　要：扁挤压筒是挤压大型铝壁板的重要工具,也是关键技术之一。与圆挤压筒相比,由于扁挤压筒型腔的线型特殊,理论计算相当困难,很难有精确的理论解。同时,非中心对称的型腔使挤压力的分布也不均匀,使得以均匀分布挤压力作为边界条件的数值计算产生了相应的误差,也使理论计算更加困难。本文制作了1∶18的环氧树脂扁挤压筒整体模型,用低弹模的环氧树脂材料作挤压材料模拟挤压工况并将应力加以"冻结",然后通过光弹性实验研究分析了挤压筒挤压时挤压力的分布特点以及筒体内部的应力场情况。结果分析得出:挤压力沿型腔高度大体上是均匀分布的,但沿型腔周向有着明显的变化;并在型腔的长轴位置出现应力集中。该实验结果为扁挤压筒的强度计算及结构设计提供了参考依据,也与数值分析解起到相互佐证的作用。如果把扁挤压筒的受力模型简化成中间带椭圆孔的无限大平面的弹性力学模型,理论最大应力值与实验结果比较接近。Flat container is one of the most important tools for extruding big thin-wall Aluminum wainscot,and also is a key technology.The shape of the flat container′s cavity is different from the round container′s.It is very difficult to acquire the theoretical results for that.At the same time,the non-centrosymmetric cavity induces asymmetrical distribution of the extruded pressure,and brings corresponding error of the numerical calculation based on the boundary conditions of symmetrically distributed pressure,and also makes theoretical calculation more difficult.We made a expoxy resin flat integral model with the ratio 1∶18.The experiment simulated the extruding process with the flexible expoxy resin as extruded materials and the stress was 'freezed' at 120°C.Photoelastic method was used to analyze the extruded pressure and stress distribution in the working flat extrusion container.The experimental results show that the extruded pressure is almost uniform along the height of the cavity but not even around the cavity.There are stress concentrations at the ends of the long axis of the cavity.The results may not only be adopted for structure design and strength evaluation of the container,but also collated with the values from the numerical calculation.If the loaded flat extrusion container is predigested as a model of a infinite plane with a ellipse hole in the center,the maximum theoretical stress is quite closed to that measured from the experiment.

关 键 词：扁挤压筒 挤压力 型腔 受力模型 挤压材 椭圆孔 光弹性 均匀分布 理论计算 无限大 

分 类 号：O441[理学—电磁学] TG375.43[理学—物理]