摘要
本文提出了用解析法求解平面应力问题时，主应力方向的一种简易判断的方法，并用应力圆加以证明。
In this paper, the authors put forwand and prove an easy method that can be applied to judge the major stress direction under surface condition.
关键词
平面应力状态
主应力方向
应力圆
材料力学
surfacial stress condition, direction of major stress, stress circle
