Reliability of Laminated Composite Plates

This thesis deals with reliability analysis of laminated composite plates subjected to transverse lateral pressure loads. Input parameters to strengths of the plates such as applied transverse lateral pressure loads, elastic moduli, geometric and ultimate strength values of the plates are treated as basic design variables, and specific probability distributions are applied to them to take into account the variability nature of these basic design variables. Based on the statistical information on the basic design variables, these variables are pseudo-randomly generated in accordance with the corresponding probability distributions by using statistical sampling techniques. Generated random values of the basic design variables corresponding to the applied loads, elastic moduli and geometric values are substituted into various laminated plate theories which can accommodate different lamination schemes and boundary conditions to assess the probabilistic strengths of the plates. The limit state equations are developed by using maximum stress, maximum strain, Tsai-Hill, Tsai-Wu, Hoffman and Azzi-Tsai-Hill failure criteria. Calculated probabilistic plate strengths and generated random values of the ultimate strength basic design variables of the plates are substituted into the developed limit state equations to define the failure or survival state of the plates. In solving the limit state equations, structural reliability techniques are adopted and evolved appropriately for the reliability analysis of the plates. Developed reliability analysing algorithms are applied to laminated plates from experiment to check its validity. Finally, the EUROCOMP Design Code is compared with the developed reliability analysis procedures by applying the both approaches to the strengths of laminated plates