Matrix Crack Effects on Composite Beams with Damage Tolerant Non-Traditional Layups

Abstract

Two traditional layups built from 0°/45°/90° plies and two recently proposed alternative non-traditional layups built from 5° /65° plies are analyzed in this paper. It was recently shown experimentally that using such off-axis plies in a composite laminate will result in a more damage tolerant structure. A cantilever beam with two traditional layup composite laminates and two non-traditional layup composite laminates is considered in this paper. Both traditional and non-traditional layup schemes are chosen such that they are "hard" laminates, i.e, much stiffer in the longitudinal direction than the lateral direction. The damage is simulated on the beams using a matrix crack model. The reduction in extensional and flexural modulus is discussed for both traditional and non-traditional laminates with different damage levels in the beam. For traditional and non-traditional composite laminates, the tip deflection of beam with constant tip loading and natural frequencies for different damage levels is determined and presented. It is found that the non-traditional layups tend to moderate the behavior of the traditional layups and show better damage tolerance with respect to matrix cracking.