DAMAGE TOLERANCE ANALYSIS OF COMPOSITE TRANSPORT FUSELAGE STRUCTURE

摘要

This paper describes the development of a technique for predicting the failure strength of fiber reinforced advanced composite structures which have damage induced cracks and flaws. The technique, described as a Damage Zone Model (DZM) simulates the manner in which the stress concentrations arising from such flaws affect the stable growth of damage and ultimately failure strength of the structure. The concept of a DZM is to describe the multiple damage modes which occur in laminated composite structures via a strain softening material law which permits controlled unloading of material at, for example, a crack tip as applied loads and the size of the crack increase. The technique has been implemented in a commercially available nonlinear finite element code and has been subjected to extensive experimental verification. Experimental fracture strength for a wide range of test specimen sizes and materials have been predicted to a degree of accuracy unobtainable with more conventional fracture mechanics techniques. As an analytical tool it may prove invaluable in designing lighter, safer composite products more quickly and with less testing.