Final report on development of the progressive failure model for composite bolted joints based on stiffness reduction scheme

In D1.2 [1] an interim report was presented on the development of a computational model for the prediction of the initiation and growth of damage in composite bolted joints based on the stiffness reduction scheme. The present report describes developments to the model since D1.2 which include developments to allow modelling of non-linear transverse and shear behaviour. Also described are some studies on lamina and laminate failure analysis which have helped to clarify the effects of shear stress in failure of composites, as well as the application of the models to single elements, and specimens with holes subjected to tensile loading. Comparisons with experimental tests from Workpackage 3 are made. This report is organized as follows. In this section, the physical processes in failure are discussed. Subsection 1.2 discusses the effect of matrix cracking on the laminate. Failure criteria for composite materials are discussed in subsection 1.3. The material properties that are affected, for different types of failure are discussed in subsection 1.4.