Estimation of fatigue curves for design of composite laminates

A statistical method for estimation of tolerance bounds for uncertain variables is presented. The method is used in conjunction with regression analysis results to estimate tolerance bounds for fatigue relations, such as e-N and S-N curves, for prediction of the fatigue life of composite laminates in design. In general, this is not a very user-friendly method. A simplification based on fulfilment of a certain assumption about the available test data is introduced, and a graphical representation of the results by the so-simplified method is presented that provides easy-to-use results for practical purposes, such as for design. Applications are demonstrated by examples.