83 Principal stress主应力 应力主面- a principal plane of stress 主应力- a principal stress 应力主轴- a principal axis of stress Plane problems平面问题 0=(o+ov/2+ VI(ox-Oy)/212tx 2 2=(x+a3)2-V(ox-y)2 2 tan(o, x)=(o-ox)txy= txy/o-oy) 0 soro 0,to,=o +o Invariants of the state of stress 徐汉忠第一版20007 弹性力学第二章徐汉忠第一版2000/7 弹性力学第二章 10 8.3 Principal stress 主应力 Plane problems 平面问题 • 1= (x + y )/2 + [(x - y ) /2]2 +xy 2 • 2= (x + y )/2 - [(x - y ) /2]2 +xy 2 • tan(,x)=(- x )/ xy= xy /(- y ) (= 1 or2 ) • 1+2=x+y Invariants of the state of stress • 应力主面-a principal plane of stress • 主应力-a principal stress • 应力主轴-a principal axis of stress