Innovative Approaches for the Flaw-Tolerant Design and Certification of Airframe Components Navy SBIR FY2008.2 Sol No.: Navy SBIR FY2008.2 Topic No.: N08-131 Topic Title: Innovative Approaches for the Flaw-Tolerant Design and Certification of Airframe Components Proposal No.: N082-131-0118 Firm: Engineering Software Research & Development, Inc. 111 West Port Plaza, Suite 825 St. Louis, Missouri 63146 Contact: Barna Szabo Phone: (314) 744-5021 Web Site: www.esrd.com Abstract: The principal objective of the proposed Phase I SBIR project is the development of a reliable predictive capability for the evaluation of flaw tolerance in metallic and composite airframe components, given part specifications, material properties, initial flaws, such as voids, inclusions, heterogeneous grain structure and design load spectra. The proposed concept is based on the idea that the safe life methodology and the flaw tolerance approaches fit within the same paradigm if we associate failure initiation and crack propagation events with deformation states of representative volume elements. The paradigm applies to metals and composites. The critical values of the deformation states depend on the material systems under consideration. The methodology of verification and validation will be applied, utilizing existing experimental data and the concept of hierarchic multi-scale models already supported by ESRD's proprietary software StressCheck. Because statistical variations in the manufacture and therefore the mechanical response of structural components are unavoidable, prediction of structural and strength responses must be understood in a statistical sense. Benefits: The results of the proposed work will support condition based & reliability centered maintenance decisions for high value military and civilian assets through the application of mathematical models based on verified and validated numerical simulation technology. One of the important commercial applications is the support of probabilistic structural reliability analysis. Return