Prediction of transverse crack initiation in [0 _m/90 _n] _s cross-ply CFRP laminates subjected to fatigue loading by static tensile test

A method to predict quantitatively the first of transverse cracks accumulated in the various types of [0 _m/90 _n] _s cross-ply carbon fiber reinforced plastic (CFRP) laminates subjected to fatigue loading was proposed. On the basis of the assumption that the mechanism of transverse crack initiation is equivalent to that of transverse crack increase in the earlier stage of fatigue within low transverse crack density, the cycles at which a transverse crack initiates are calculated by applying the normalized modified Paris law, which shows the relationship between the transverse crack density growth rate and the normalized energy release rate range associated with the transverse crack formation. When the constants of the normalized modified Paris law are given with an arbitrary cross-ply laminate, the proposed method makes possible to predict the initiation of a transverse crack in the other various types of cross-ply laminates under fatigue loading by only measuring the stress at which a transverse crack initiates under static tensile loading.