Experimental Characterization and Numerical Modeling of ±45° Tensile Laminates

Abstract

This paper investigates the combined effect of stacking sequence and interlayer toughening on the mechanical response and failure modes of ±45 carbon fiber reinforced laminates, through experimental and numerical studies. Two material systems (T800H/3631, T800S/3900) and three stacking sequences (4 double plies, 4 plies, 8 plies) have been examined. Digital Image Correlation (DIC) and a high resolution edge camera were utilized to capture the intricate crack patterns in each ply. This paper also addresses the challenge of the nonlinear in-plane shear characterization of each lamina, and proposes an amendment to the existing ASTM standard to obtain the lamina shear strength and the in-situ non- linear response. The complex progression of micro-damage, matrix cracks and delamination as well as the final two-piece failure were captured by the enhanced semi-discrete damage modeling (eSD2M) framework. A parametric study was performed to reverse-engineer the most critical parameters such as interlayer strengths and toughnesses. The obtained values reflect the difference in the interlayer composition between the two material systems.