Experimental and Computational Study of Ultra-Low-Cycle Fatigue of Fabric-Reinforced GFRP

Abstract

The development of weight-efficient reusable launch systems has increased the urgency of problems associated with ultra-low-cycle fatigue. In this paper, one-sided three-point bending cyclic tests of GFRP specimens were performed. Parallel to the cyclic tests, registration of acoustic emission signals has been performed to identify the main damage mechanisms underlying ultra-low-cycle fatigue of fabric-reinforced composites. The obtained displacement-time diagrams showed a noticeable effect of creep on the deformation process. It was found that fiber fracture is the main mechanism of microdamage accumulation. A phenomenological three-element model based on the Norton-Bailey law and the Masing structural model was proposed. The model allowed describing both the deformation process of the specimens in time and their durability at different load levels. An optimization algorithm based on the deformable polyhedron method was used to find the optimal set of the model parameters.