Fatigue in composites refers to the weakening of a material caused by repeatedly applied loads or stress cycles over time. When a composite material is subjected to cyclic loading, small cracks or microdamage can form within the material, which may grow and lead to failure after a certain number of loading cycles. This is a significant consideration in the design and analysis of composite structures, especially in applications subjected to repeated stress, such as in aerospace, automotive, or civil engineering.

In one of our other packages, we have used the UMAT subroutine in Abaqus to simulate fatigue in composites in two-dimensional space. The current project is more comprehensive, as it addresses composite fatigue in both 2D and 3D spaces. So you can use it for the simulation of both shells and solids. In this project, you will first become familiar with simulating composite fatigue in 3D space using the Abaqus UMAT subroutine. Then, we will provide a complete UMAT code along with Abaqus files for extending the simulation to 3D space, enabling the 3D simulation of composite fatigue in Abaqus.