A numerical parametric study on delamination influence on the fatigue behaviour of stiffened composite components

Abstract. This paper investigates the fatigue phenomenon in Carbon Fibre Reinforced Plastic (CFRP) composite materials. Fatigue is a major problem in composite materials, due to their complex microstructures and inhomogeneous properties. In composite materials, fatigue is caused by cyclic loading, which leads to the accumulation of damage and eventually failure. This is related to several factors such as material properties, geometry, loading conditions, and environmental conditions. The fatigue life of composite materials is usually much lower than that of metals, and it is often catastrophic and unpredictable. Therefore, it is mandatory to understand behaviour of composite materials subjected to cyclic loading condition and to develop strategies to improve their fatigue performance. To this end, a Paris Law-based module has been implemented in the well-establish SMart-time XB (SMXB) procedure, being able to accurately numerically simulate the delamination growth caused by cyclic loads in complex composite structures. This process, which takes advantages of the mesh and load independency of the SMXB method in the evaluation of the delamination growth, has been implemented in the Ansys Parametric Design Language to create a highly versatile and parametric procedure. A numerical parametric study has been carried out to investigate the behaviour of a pre-existing circular delamination under cyclic loading, to assess the influence of delamination radius and thickness on the delamination growth. The results of this study will provide important insights into how delamination radius and thickness affect the delamination growth and the durability of composite structures. This study will help to inform the design of composite structures for various applications.