INTERLAMINAR STRESS RECOVERY OF MULTILAYER COMPOSITE STRUCTURES Christian Fagiano, Mostafa M. Abdalla, Zafer G¨ urdal Aerospace Structures Chair, Delft University of Technology Kluyverweg 1, 2629 HS Delft, The Netherlands c.fagiano@tudelft.nl S UMMARY Despite their merits, composites have weakness in transverse strength making them prone to failures such as delamination when subjected to high interlaminar stresses. Onset of delamination can only be accurately predicted if an appropriate evaluation of the inter- laminar stress fields is obtained. An efficient post-processing recovery procedure evaluating interlaminar stress fields of moderately thick-thin multilayer composite structures has been presented in the previous work of the authors. Comparisons with exact solutions of benchmark problems have con- firmed the reliability of the approach. In the present paper, this procedure is combined with the commercial finite element soft- ware ABAQUS 6.8. Attention is also addressed to multilayer shell structures. Keywords: Layered shell structures, Intra-interlaminar stress fields. I NTRODUCTION Increasing use of composite laminates in a wide range of applications has underlined the need to understand their major interlaminar mode of failure, delamination. Composites are prone to delamination when subjected to high interlaminar stresses. Once interlam- inar stress fields are evaluated, location and crack form are usually assumed in advance in most of the theoretical studies on onset of delamination. Consequently, an appropriate evaluation of interlaminar stresses leads to an accurate prediction of the failure mecha- nism. Most research activity has been focused on procedures aimed at improving the accuracy of finite element solutions obtained by means of displacements based models. C 0 continuous elements usually lack the characteristics of having continuous stresses at the inter-element boundary. Stress distributions from such elements are inclined to exhibit oscillatory be- havior, especially for thin plates, making the judgement of results difficult [1]. An efficient interlaminar stress recovery technique has been presented in the previous work of the authors [2]. This procedure is based on a domain decomposition approach for