GUEST’s or TRESCA’s THEORY

MAXIMUM SHEAR STRESS THEORY (GUEST’s or TRESCA’s THEORY)

                 According to this theory, the elastic failure occurs when the greatest shear stress reaches a value equal to the shear stress at elastic limit in a simple tension test. This theory is considered for ductile materials, since shearing doesn’t occur in brittle materials.

(½)(σ₁ – σ₃) = (½)σ_e           or

                                                              σ₁ – σ₃    =      σ_e

                  The maximum shear stress theory is also known as Guest’s or Tresca’s theory.