A comparison of the predictive capabilities of current failure theories for composite laminates

This paper presents a unique and comprehensive comparison between the predictions of internationally recognised failure theories for fibre-reinforced polymer-composite laminates. The theories were applied by their originators (or their colleagues) to carefully selected test cases covering a wide range of lay-ups, materials and in-plane loading conditions. Key features in each theory are identified including: types of failure models employed, whether linear or non-linear analysis was carried out, reliance on software and numerical methods, allowance for thermal stresses and identification of modes of failure. The results (initial and final failure envelopes and representative stress/strain curves) have been superimposed to show similarities and differences between the predictions of the various theories. In addition, bar charts were constructed to demonstrate the levels of agreement between the predicted initial and final failure stresses and strains. Sources of discrepancies between the predictions of the various failure theories are discussed. The originators have the opportunity to comment on and compare their theoretical predictions with experimental results in the second part of this Exercise which will be published separately. (C) British Crown Copyright 1998, Defence Evaluation and Research Agency, published by Elsevier Science Ltd with permission.