Abstract:
In this paper, a method based on the continuous damage mechanics(CDM) model is proposed for predicting the failure of unidirectional laminates with out-of-plane wrinkles and varying aspect ratios. Initially, a numerical analysis model was established using ABAQUS to investigate five 5-layer laminates with different aspect ratios of out-of-plane wrinkles. The prediction of tensile failure load and progressive damage history were performed by programming the USDFLD subroutine and utilizing the continuous shell element(SC8R). The accuracy of the proposed analysis method was validated through comparison with experimental results. Furthermore, a numerical analysis model was developed for fifteen layers of large-thickness unidirectional laminate with three types of out-of-plane wrinkles and various aspect ratios based on the thickness distribution of Aerodyn 2 MW-45.3 m blade spar cap. To examine the influence of shear effect on laminate performance, a VUMAT subroutine was implemented to predict the impact of wrinkles on tensile and bending properties using the 3D Hashin criterion. The results indicate that wrinkle aspect ratio significantly affects the bearing capacity of spar caps, as both tensile and flexural properties gradually decrease with increasing wrinkle aspect ratio for spar caps. Additionally, due to coupling effects between strain ε
33 in thickness direction and out-of-plane strain ε
13, stratification occurs in high-strain areas leading to significant reductions in stiffness and strength.