B Coordinate system for plane stress problem 平面应力问题的坐标系 X and y axes are in the middle plane and z axis is perpendicular to the middle pla ane x,y轴放在薄板的中面内,z垂直于中面 徐汉忠第二版2001/10 弹性力学第二章徐汉忠第二版2001/10 弹性力学第二章 5 B. Coordinate system for plane stress problem 平面应力问题的坐标系 • x and y axes are in the middle plane and z axis is perpendicular to the middle plane. • x,y轴放在薄板的中面内，z垂直于中面