16-13 对于图 16-42 所示平面应力状态,各应力分量的可能组合有以下-|||-几种情形,试按最大切应力准则和畸变能密度准则分别计算此几种情形下的-|||-计算应力。-|||-(1) (sigma )_(x)=40M(P)_(a) ,(sigma )_(y)=40MPa ,_(xy)=60MPa;-|||-(2) (sigma )_(x)=60MPa ,(sigma )_(y)=-80MPa ,_(xy)=-40MPa;-|||-(3) (sigma )_(x)=-40MPa ,(sigma )_(y)=50MPa =0;-|||-(4) (sigma )_(x)=0 .(sigma )_(y)=0 ,_(xy)=45MPa-|||-↑σy-|||-σx-|||-Txy-|||-t-|||-图 16-42 习题 16-13 图