Effect of Shear Stresses on Failure of Fibrous Composite Materials Accounting for Nonlinear Material Behavior

Variation of shear stresses τ xy on failure behavior of different composite materials was investigated for two types of composites; boron-epoxy narmco 5505 and carbon-epoxy as4 (3501-6). the effect of material nonlinearity on failure behavior of unidirectional fibrous composite laminates was considered for several fiber-orientation angles; θ=15, 30, 45, 60 and 75 degrees. an energy-based nonlinear material model was adopted to predict the mechanical properties of a unidirectional composite lamina. a compatible failure criterion for nonlinear composite materials was utilized which incorporates the material model into the failure criterion. the resulting failure envelopes were compared for all the cases.