The effect of the transverse crack on the ultimate tensile strength (UTS) for carbon fiber reinforced plastic (CFRP) cross-ply laminates was studied experimentally and analytically. For various stacking sequences of CFRP composites, quasi-static tensile tests were carried out. And the fiber bundle strength of 0-degree ply was almost constant. Therefore, it was concluded that there was little notch sensibility in spite of the existence of transverse cracks. A new numerical model based on the

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... te element method was proposed to investigate the inner micro damage process. In the model the elastoplastic relation of epoxy matrix was considered effectively and the progress of the inner fiber breakage was obtained. Then, using this model, we conducted the simulation based on the Monte-Carlo method. Based on the analysis results of the proposed model, it was shown that the plastic regions at the tip of transverse crack reduce the concentration of stress, and the bundle strength was not affected by the existence of transverse cracks.