Innovative Capability to Quantify Fatigue Damage and Assessment of Endurance Limit in Spectrum Load Histories Navy SBIR FY2010.2 Sol No.: Navy SBIR FY2010.2 Topic No.: N102-113 Topic Title: Innovative Capability to Quantify Fatigue Damage and Assessment of Endurance Limit in Spectrum Load Histories Proposal No.: N102-113-0540 Firm: Technical Data Analysis, Inc. 3190 Fairview Park Drive Suite 650 Falls Church, Virginia 22042 Contact: Nagaraja Iyyer Phone: (703) 237-1300 Web Site: www.tda-i.com Abstract: Develop analytical and empirical formulations based on critical test data for reliable fatigue and crack growth life predictions of long spectrum histories involving high frequency small amplitude vibratory loading cycles. Extend these formulations to account for surface conditions, treatments and finishes, and residual stresses. Incorporate these analytical formulations in Navy programs such as FAMS, FASTRAN, and UNIGROW for reliable fatigue and crack life predictions. Investigate improvements to existing voice-coil servo-hydraulic technology and other alternative accelerated fatigue test techniques for application to spectrum loading with high-frequency content on commonly used test laboratory specimens. Develop necessary software and hardware for improved fatigue testing at high frequencies involving servo-valve and other technologies by closely working with a test machine manufacturer. Benefits: The proposed effort will use the latest improvements in both laboratory testing and analytical techniques to reliably assess damage and hence life of structural components that experience divergent service loadings, with varying surface conditions and treatments. The effort will result in improved fatigue testing techniques, both hardware and software, at high frequencies to assess notched and un-notched material response, and crack growth behavior at high-cycle, very-high-cycle, and combined cyclic fatigue load histories. Rigorous estimates of endurance limit and fatigue crack growth thresholds under spectrum loading for many structural materials will be made. Reliability calculations of structural components are expected to improve significantly by the enhanced analytical formulations developed in this effort, supported by the extensive testing and data generated. The analytical formulations will be incorporated into Navy and other commercially available life prediction programs for wide use in aerospace, automotive, machinery and research/university environment. Return