Innovative Analysis Tool for Damage Growth From Loaded Composite Fastener Holes

Global Engineering and Materials, Inc. (GEM) along with its team members, University of Dayton Research Institute (UDRI), Lockheed Martin (LM) Aero, and Sikorsky Aircraft will develop an add-on toolkit for Abaqus with high fidelity prediction of residual strength and life of laminated composite structures with fastener holes. A discrete crack network model for damage prediction developed under the Phase I study will be extended for a composite bolted joint under a combined bypass and bearing loading. In addition to the tension and shear induced failure modes studied in Phase I for open hole composite laminates, compression induced damage modes will be extensively studied. Critical damage modes such as interlaminar shear induced matrix cracking and fiber kink bands in compression will be included in the discrete damage modeling framework. The BSAM solution module will be validated by using LM Aero and Sikorsky test data as well as interrupted fatigue loading testing cases conducted at UDRI. The validated BSAM solution model will then be implemented in Abaqus via a user-defined element with additional enriched nodal DOFs. The integrated Abaqus toolkit will be verified and validated against a suite of bolted joint test cases collected by LM and Sikorsky.