Characteristic length determination of notched woven composites

In this manuscript, the progressive failure analysis was employed to predict the final failure of notched woven glass/epoxy composite laminates under tensile loading. A user-defined material model (UMAT) in the Abaqus finite-element package was developed to utilize the 3D progressive failure analysis feasible. Three types of stress-based failure criteria as Max. Stress, Yamada-Sun, and Tsai-Wu were implemented in Abaqus to predict the damage initiation in the notched woven composites. Instantaneous and recursive property degradation rules were employed to simulate damage propagation. A numerical procedure was developed to find the characteristic length (CL) in the notched woven composite laminates without test. The various notched and unnotched woven glass/epoxy specimen were fabricated by vacuum-assisted hand layup technique. Four groups of experiments were performed to predict the hole size effect on the strength of the notched laminates and verify the strength predicted by the progressive damage modeling. Numerical results were in good agreement with the test results. More than above, it was verified by the experiment that the CL obtained by the progressive damage analysis is a reliable and simple method to design notched woven laminates.