MONITORING THE INTEGRITY OF COMPOSITE STRUCTURES

A method is proposed to predict the future load response of structures made of composite materials. The method makes the predictions on the basis of past load-strain data. The method was developed for structure s subjected to monotonically increasing or to random cyclic tensile lo ads. A computer code PREDICT was written which, in real time, can prov ide predicted values of residual strengths and number of cycles to fai lure from measured data. Tests were performed to evaluate the validity of the method using specimens made of different materials, lay-ups, a nd geometries. The specimens were subjected to monotonically increasin g or to cyclic tensile loads. During the tests, the residual strengths and number of cycles to failure were predicted, and were compared to the actual value generated in the tests. The predicted and measured Va lues were in good agreement lending confidence to the method.