Novel Method to Utilize Multi-scale Physics-based Technique for Crack Path Determination in Fiber-reinforced Composites Navy SBIR FY2016.1 Sol No.: Navy SBIR FY2016.1 Topic No.: N161-010 Topic Title: Novel Method to Utilize Multi-scale Physics-based Technique for Crack Path Determination in Fiber-reinforced Composites Proposal No.: N161-010-0675 Firm: Global Engineering and Materials, Inc. 1 Airport Place, Suite 1 Princeton, New Jersey 8540 Contact: Eugene Fang Phone: (609) 356-5515 Web Site: http://www.GEM-Innovation.com Abstract: Global Engineering and Materials, Inc. (GEM) along with its team member Northrop Grumman Corporation (NGC) propose to develop a multiscale and generalized discrete crack damage prediction toolkit for fiber-reinforced composites subjected to static and cyclic loading. GEM will draw on its extensive experience in composite progressive damage analysis and leverage its current NAVAIR sponsored composite bolted and bonded joints programs and data collected from NGC under their Air Force sponsored Tech Scout 2 program for module enhancement and validation under this Phase I program. In order to capture a curvilinear matrix crack path and its interaction with an intersected delamination crack, a slanted phantom-paired X-FEM approach coupled with a segmented cohesive model will be developed for the kinematic description of crack network without remeshing. The co-existence of both discrete cracking and diffuse damage has motivated us to develop a multi-scale approach based on an N-phase cylinder micromechanics model for extraction of static and fatigue damage accumulation at an integration point of a discrete cracked element. To bridge the gap between stress-life driven crack initiation and Paris type description for crack propagation, a unified fatigue damage prediction model will be implemented to capture the delamination initiation and propagation under fatigue loading. Benefits: The results from this research will have significant benefits and commercial application in the NAVAIR, DoD labs, and aerospace industries. As concluded from recent Tech Scout 1 and 2 programs sponsored by Air Force, Air Force structural integrity managers lack tools for rapidly assessing remaining life and residual strength of bolted composite structures. There is an emerging need to predict the strength, durability, and damage tolerance of composite joints at the detailed level to assure continuing airworthiness. Major aircraft manufacturers such as Boeing, LM, and NGC are exploring innovative approaches using emerging tools to be the path towards closing the capability gap associated with fatigue life prediction of composite structures. Driven by the advancement in NDI based damage detection, damage informed rational repair, and use of physics based failure prediction to reduce the reliance on test-driven empirical damage parameters, discrete damage description coupled with a multiscale modeling process has provided more benefits in terms of solution fidelity, use of measurable physical properties, and direct correlation with test data. We envision that the multiscale and generalized discrete crack damage prediction toolkit developed under this SBIR will have great benefits and commercial viability to both the DoD labs and commercial industries because of its unique capabilities and its integration with Abaqus, a commercial finite element software that has been used extensively by both the DoD labs and aerospace industries. Return