چكيده به لاتين
In recent decades, the use of composite materials in engineering structures has increased dramatically. Therefore, it is necessary to understand the concept and mechanisms of damage to these materials. Among the most common damages in composite materials, delamination is the catastrophic mode of failure in these materials. Because of delamination, the phenomenon of stress transfer, which is one of the advantages of the laminated composites, does not appear between layers. The delamination in laminated composites under cyclic loading is typically analyzed by two methods: fracture mechanics and the cohesive zone model.
In this study, a model was used based on the linking of damage mechanics and fracture mechanics. Because the damaged area is essential, the focus of the present study was on calculating the cohesive zone length. The accuracy of the crack growth rate prediction increased due to modifying the cohesive zone length in the pure mode I and II, making better results in comparison with the previous models. There was not an analytical equation for calculating the cohesive zone length in mixed-mode loading. Therefore, a new equation was presented to tackle the problem. New equation is proposed to calculate the length of the cohesive zone in the mixed-mode I/II in which mixed-mode cohesive zone length is a function of cohesive zone length in the pure mode I, II and mode ratio. The accuracy of the suggested equation was approved by the acceptable results.
