Verification of Closed Form Mixed Mode Strain Energy Release Rate Expressions for Unidirectional Laminate Configurations

Enjuto, P., Lobo, M., and Mabson, G.E.

2019 AIAA SciTech Forum, AIAA 2019-1042, 7-11 January 2019, San Diego, California.

A closed-form fracture methodology based on first order shear deformable plate theory (FSDT) was developed in Reference 1. By using a sub-laminate model and adopting transverse shear-deformable laminate theory, general expressions for total strain energy-release rate (SERR) and its individual components were derived. Making use of the first order shear deformable plate theory, closed-form expressions for the calculation of the individual modes of the strain energy release rate for traditional unidirectional laminate test specimens used to obtain fracture toughness properties (Double Cantilever Beam, End Notch Flexure and Mixed-Mode Bending) were introduced in Reference 2. The present work presents verification of these closed form expressions through finite element modeling using shell elements, compatible with the assumptions inherent to the FSDT fracture methodology.