Comprehensive Bonded Joint Analysis Method Navy STTR FY2012.A Sol No.: Navy STTR FY2012.A Topic No.: N12A-T004 Topic Title: Comprehensive Bonded Joint Analysis Method Proposal No.: N12A-004-0029 Firm: M4 Engineering, Inc. 4020 Long Beach Blvd Long Beach, California 90807 Contact: Daniel Hammerand Phone: (562) 981-7797 Abstract: M4 Engineering, Inc. and Sandia National Laboratories propose to create a unique bonded joint analysis and design software tool. Surrogate traction-separation models will be created that efficiently capture the behavior that occurs for real bonded joints. Mixed mode loading, including compressive normal tractions and relative displacements will be captured and used in an extended cohesive zone element to be developed and implemented in ABAQUS using its user subroutine interface. The mathematical forms for the surrogate traction-separation interface models will be developed and populated using high fidelity numerical models which include explicitly modeled adhesive layers. These models will utilize the nonlinear viscoelastic constitutive equation for polymers developed at Sandia. This material law captures the complete range of polymer behavior which cannot be captured fully by any known plasticity model. Furthermore, not only is this model useful for simulating variable thermal histories, it is also useful for predicting both adhesive and cohesive failure of polymer epoxies, as shown in the literature. An experimental program necessary to fully populate the high fidelity models and validate the surrogate traction-separation models will be delineated. Successful execution of this proposal will allow a commercially viable software tool to be developed in Phase II. Benefits: The comprehensive and quantitative bonded joint modeling tool will dramatically improve the analysis and design of bonded joints. The technology will be incorporated into a software tool which utilizes commercially available software for finite element analysis (SIMULIA/ABAQUS) and design optimization and parameter estimation (DAKOTA). The subject matter expertise of the proposal team will be embedded into the inner workings of the tool, while users will interact at a high level with an intuitive graphical user interface (GUI). The developed tool will find application not only at the Naval Air Systems Command (NAVAIR) which is the sponsoring agency, but also at other DoD labs. Furthermore, commercial aircraft companies such as Boeing and Airbus will be able to take advantage of the developed tool for aging aircraft repair where bonded patches are often used to repair small cracks and corrosion damage in the aircraft. Finally, Sandia National Labs has proposed and demonstrated technology for bonded composite repair of the U.S. civil and military infrastructure, including bridges, buildings, communication towers, pipelines, and mining equipment. Those concepts will benefit from the technology to be actualized herein. As such, the commercial demand for the final software tool is expected to be substantial. Return