... 29 λ3 − Iσ λ2 − II λ − IIIσ = (2.26) where the symbols Iσ , II and IIIσ denote the following scalar expressions in the stress components: Iσ II IIIσ 30 = σ11 + σ22 + σ33 = ii = tr σ 2 = −(σ11 ... invariants Iσ , II and IIIσ Example 2-3: Stress Transformation Victor Saouma Mechanics of Materials II Draft 2.5 †Simplified Theories; Stress Resultants Show that the transformation tensor of direction ... Victor Saouma Mechanics of Materials II Draft 10 KINETICS Figure 2.5: Differential Shell Element, Stresses Figure 2.6: Differential Shell Element, Forces Victor Saouma Mechanics of Materials II Draft...