Evaluation of failure prediction in composite laminates: background to ‘part C’ of the exercise

Over the past 10 years, an international study has been underway to determine the accuracy of current theories for predicting failure in polymer composite laminates. The study, known as the World-Wide Failure Exercise (WWFE), has been carried out in three distinct stages (referred to as Part A, Part B and Part C). Two previous special editions of the Composites Science and Technology journal were dedicated to the first two stages. Part A (Vol. 58, No. 7, 1998) contained detailed descriptions of 14 leading failure theories and predictions by each for a set of test cases defined by the organisers of the exercise (the authors of this paper). Part B (Vol. 62, Nos. 12–13, 2002) provided a detailed comparison between the theoretical predictions and the experimental results, in order to assess the level of maturity of the theories. Part C is aimed at serving a number of purposes. It extends the breadth of the study by including four additional theories that have emerged since the WWFE was first initiated. It provides a comprehensive view on the perceived strengths and weaknesses of all of the leading failure theories considered. It provides direction to designers on choice of theory and likely confidence in the prediction. It provides recommendations to the composites research community as to where efforts should be focussed to develop improved failure prediction tools. This introductory paper to the third special edition contains a detailed description of the process adopted for carrying out ‘Part C’, so that the composites community can draw appropriate conclusions on the overall probity (and hence reliability) of the study.