Abstract
In order to establish the simple method to monitor the carbon fiber reinforced plastics (CFRP) structure, the relation between transverse crack density and sonic velocity was investigated. Tensile and fatigue tests were conducted on the [0/90_2]_s, cross-ply laminates. Both tests were periodically terminated and X-ray observations and wave velocity measurement were conducted. The variation in the wave velocity was measured as a function of normalized Young's modulus and transverse crack density. Normalized Young's modulus is well-predicted with Complete Parabolic Shear-lag analysis, whereas the variation in wave velocity is not affected by transverse crack accumulation.
