Innovative Approaches for Improving Progressive Damage Modeling and Structural Life Prediction of Airframes Navy SBIR FY2009.1 Sol No.: Navy SBIR FY2009.1 Topic No.: N091-008 Topic Title: Innovative Approaches for Improving Progressive Damage Modeling and Structural Life Prediction of Airframes Proposal No.: N091-008-1111 Firm: Global Engineering and Materials, Inc. 11 Alscot Drive East Lyme, Connecticut 06333 Contact: Jim Lua Phone: (860) 367-4970 Web Site: www.GEM-Consultant.com Abstract: An automatic software tool for 3D fatigue crack growth prognosis of structural systems under realistic complex loading will be developed by integrating a unified growth model with a mesh independent extended finite element toolkit in ABAQUS. The tool will be able to model arbitrary non-planer crack growth over multiple growth regimes with an arbitrary stress ratio without user intervention or remeshing. GEM has established the business partnership with SIMULIA (ABAQUS) and secured commitments for technical support from Bell Helicopter, who will provide supporting data, information, and expertise. In addition, our consultant, Professor Liu from Clarkson University, will aid in fatigue model development, and provide existing fatigue damage model for the toolkit integration. The multi-faceted feasibility study consists of developing an add-on ABAQUS toolkit that will enable the following: 1) a new unified fatigue crack growth modeling technique that captures the stress ratio effects under both uniaxial and multiaxial load; 2) arbitrary insertion of multiple 3D cracks that are independent of the finite element mesh; 3) characterization of a growing crack using the level set and fast marching method; and 4) demonstration of the applicability and computational efficiency of the developed toolkit at component and structural level. Benefits: The results from this research will have significant benefits and commercial application in the NAVAIR, aerospace, DoD labs, and rotorcraft industries. It will result in : 1) a commercially viable, accurate, computationally efficient, and user-friendly residual life assessment tool for charactering fatigue crack growth and perform damage tolerance design and analysis; 2) an integrated analysis framework for fatigue damage prognosis and health management of air platform; 3) a virtual testing tool to reduce current certification and qualification costs which are heavily driven by experimental testing under various stress; and 4) innovative damage tolerance design and risk management procedures to minimize the risk of fatigue damage. The tool can be used by government agencies and private industries as follows: 1) to accelerate fatigue damage assessment, assist in decision making for effective maintenance and repairs, and design reliable structural systems to ensure the airworthiness; 2) for structural certification and design agencies to specify fatigue performance limits and safety standards; and 3) for rotorcraft and aircraft manufacturers to provide optimal designs via the effective use of new analysis tools, risk evaluation methods, and health management procedures. Return