Effects of Defects: Part B-Progressive Damage Modeling of Fiberglass/Epoxy Composite Structures with Manufacturing Induced Flaws Utilizing Cohesive Zone Elements

摘要

The Effects of Defects is important for the reliability of modern composite wind turbine blades. The DOE has sponsored a comprehensive study to characterize common manufacturing defects and establish damage growth and validation tools to contribute to a wind turbine blade reliability infrastructure. To support this development of a reliability infrastructure, progressive damage modeling of blade representative coupons has been performed. A model has been developed that is combined of both continuum and discrete modeling approaches. A user-defined material subroutine has been created and used with material properties established from experimental testing for the former, while cohesive zone elements were placed between each fiber tow to capture the fracture that occurs in these areas for the latter. Two-dimensional (2D), four-layer coupon level models were generated based on the geometry of the as-tested specimens. Results from this model were compared to the visual damage progression and stress-strain data from in-plane wave tests in tension and compression. While the uniformity of the models resulted in more dramatic changes at failure points, the progression was found to match in these cases, thereby verifying the combined continuum and discrete modeling approach.