STRENGTH THEORIES 88-2 FOUR STRENGTH THEORIESAND THEIR EQUIVALENT STRESSES 1> Theory of the maximum tensile stress ( the first strength) This theory considers the main cause of rupture to be the maximum tensile stress. The member will rupture as the maximum tensile stress reaches the strength limit in axial tension 1) Criterion of rupture a1=a;(1>0) 2)、 strength condition:σ1≤[o]; (G1>0) 3)Application range: May be applied to the members with the failure form of brittle rupture§8–2 FOUR STRENGTH THEORIES AND THEIR EQUIVALENT STRESSES 1、Theory of the maximum tensile stress（the first strength）： This theory considers the main cause of rupture to be the maximum tensile stress. The member will rupture as the maximum tensile stress reaches the strength limit in axial tension. 1)、Criterion of rupture： ;( 0)  1 =  b  1  2)、strength condition：   ; ( 0)  1    1  3)、Application range：May be applied to the members with the failure form of brittle rupture. 9