A NEW METHODOLOGY FOR THE PREDICTION OF FATIGUE FAILURE IN MULTIDIRECTIONAL FIBER-REINFORCED LAMINATES

This paper deals with the development of a new methodology for the prediction of fatigue failure in multidirectional fiber-reinforced laminates. It is proposed that the lamina-to-laminate prediction concept be refined to take into account the constrained condition of the individual laminae in a multidirectional laminate. In practical terms, this means that basic properties of the individual laminae should be obtained from constrained lamina tests. Furthermore, the prediction methodology is based on the explicit recognition that the stress state in individual laminae within a multidirectional laminate is inherently multiaxial. Two alternative methods of prediction are proposed depending on the laminate lay-up and type of loading. Examples considered show that the theory predicts accurately the failure results of a large family of laminates while requiring a minimal amount of experimental input.