Compression after impact and damage tolerance

A is the greater of the axial stiffnesses An and A22 for the sublaminate and e is the applied strain. By comparing the difference in energies to Gic, the SERR required to cause Mode I failure of the resin, it is possible to approximately predict the threshold strain below which propagation of a delamination will not occur. 

Plies Layup Threshold stress ffOi, MPa Running ioad, kN/mm Effective moduius Exxf GPa Poisson s ratio 

Hie subscnpt A denotes that the layup has symmetric ciossplies, conqiressive load per unit width equivalent to Source Ref. [21]. 

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