Matrix-Dominated Damage Process in CFRP Composite Laminates underFlexural Loading Condition

Matrix cracking is the first major failure mechanisms under flexural loading in carbon fiber-reinforced polymer (CFRP) composite laminates. This paper examines the progressive matrix damage process in the CFRP laminae. Continuum damage-based model incorporating Hashin’s damage initiation criteria and a linear energy-based damage propagation criterion is employed. Finite element (FE) model of the CFRP beam specimen is created based on meso-scale construction of the structure with respect to its manufacturing process. An experimental-computational approach is employed to established internal damage states of the laminates upon validation of the model based on measured load-deflection curve. The flexural behavior of CFRP composite beam specimen with anti-symmetric ply sequence of [45/-45/45/0/-45/0/0/45/0/-45/45/-45] is established through three-point bending test at machine crosshead speed of 2 mm/min. Results show that matrix damage initiated in central locations for the top laminae (in compression) and at edge locations for the bottom laminae beneath the loading roller. Matrixdamage is primarily contributed by transverse normal and shear stress component in the lamina. Flexural stiffness of the specimen continuously decreases with excessive degradation once matrix damage initiated. In addition, the predicted anti-symmetric distribution of the damage variable is derived from anti-symmetric sequence of the laminae.

Keywords:

CFRP Composite Laminate , Continuum Damage Model , Finite Element Simulation , Flexural Loading , Hashin’s Criteria