Probabilistic analysis of multi-step failure process of a T laminated composite in bending

This paper presents results of a theoretical and experimental analysis of the random bending strength of laminated composites. Multi-layered composites with a periodic structure of sublaminates are considered in a combined loading (bending action and plane stress) state. The random strength response of the composites is analyzed on the basis of a multi-step failure probabilistic model. Here, the multi-step failure is considered as a process in which the failure of some single structural elements (sublaminates, laminae) leads to load redistribution onto other intact elements. A numerical algorithm based on the Monte Carlo technique and respective computer code are offered The effect of scatter of structure parameters and number of sublaminates on the bending strength distribution ir analyzed in detail. Experimental confirmation is considered on an example of uniaxial bending of laminated carbon-fiber-reinforced plastics. A method for evaluation of reliability in a random combined loading is also suggested.