Elasto-plastic behavior and failure of thick GLARE laminates under bending loading

Abstract

Mechanical properties of thick GLARE1-9/8 laminates with unidirectional structure are investigated. Three-point bending tests are conducted to determine the elasto-plastic behavior and flexural strength of samples with different length. Effective longitudinal and interlaminar shear moduli of GLARE are measured based on various span method. Failure loads and failure mechanisms are determined within the range of the samples’ span-to-thickness ratio L/h=3.5...27. Micro/meso-mechanical models are involved for the analysis of experimental data. It is shown, that found values of elastic moduli agree well with simple analytical models, while the non-linear deformations of GLARE under high loading levels should be described accounting for plastic effects that arise in aluminum sheets as well as in GFRP layers. Change of failure mechanisms is accurately predicted based on the developed elasto-plasticity model involving maximum stress and maximum strain criteria. Size effects for the apparent interlaminar shear strength (ISS) of GLARE laminates are explained accounting for anisotropy and inelastic deformations of GFRP layers. It is shown, that true ISS evaluated based on the proposed model is closed to those one determined by the double-notched shear test.