Numerical modeling and experimental validation of lamina fracture and progressive delamination in composite dovetail specimens under tensile loading

In this work, a numerical simulation was conducted to investigate the lamina fracture and progressive interlaminar failure behavior of a dovetail specimen of composite fan blades. Through-thickness compression (TTC) will strengthen the interphase properties as the applied pressure increases and degrade the tensile strength combined with the in-plane shear stress, which greatly affects the overall tensile behavior on the composite dovetail specimen. This was realized with the aid of ABAQUS user subroutines VUSDFLD and VUMAT, along with an experimental validation. To demonstrate the performance of the proposed approach, two sets of tensile tests were conducted on specimens with different stacking sequences with a digital image correlation (DIC) device to investigate the deformation configurations, as well as the load-displacement curves of the gauge section. The obtained results exhibited a remarkable agreement with the simulation results, particularly in terms of the first delamination load and lamina fracture load. To further validate these observations, a sensitivity analysis was carried out. This analysis took into consideration the uncertainties associated with parameters such as the longitudinal Young's modulus, interphase properties, friction coefficient, and the position of the contact pad.