This proposal describes research that will establish a comprehensive methodology for using progressive damage analysis PDA to accurately predict impact damage and subsequent compressive residual…

This federal contract award to the University of California, San Diego (UCSD) is for research on using progressive damage analysis (PDA) to predict impact damage and subsequent compressive residual strength of stiffened-skin composite panels representative of aircraft structures. The $1,102,035 cooperative agreement is funded by NASA and directly supports the agency's Advanced Composites Project within the Advanced Air Vehicles Program. The research aims to establish physics-based analysis tools and a clear methodology for conducting PDA, ultimately reducing reliance on test-based approaches and enabling faster development and certification of composite structures. UCSD is collaborating with NSE Composites, a small engineering firm with expertise in damage tolerance and residual strength failure prediction, to ensure the modeling capabilities developed can solve real-world problems relevant to the aircraft industry. This contract does not have a set-aside designation.

This proposal describes research that will establish a comprehensive methodology for using progressive damage analysis PDA to accurately predict impact damage and subsequent compressive residual strength of stiffened-skin composite panels representative of aircraft structures. The anticipated outcome will provide both a near term methodology based on commercial finite element FE code as well as establishment of a robust and computationally efficient prediction capability based on a novel accurategeometry ISO geometric analysis IGA approach. The proposed work directly supports the advanced composites project within the NASA advanced air vehicles program as well as any programs NASA, FAA, and broader aerospace community concerned with damage tolerant composite structures. Achieving the proposed goals directly contributes to the state of knowledge in the field by: establishing physics-based analysis tools and defining clear methodology for conducting progressive damage analysis, ultimately reducing reliance on test-based approaches and thus enabling faster development and certification time for composite structures and demonstrating validation processes for analysis tools in industry user compatible format including providing an extensive experimental data library for validation of new tools to be developed in the future as technologies and computational capabilities evolve. The proposal team consists of ucsd professors hyonny KIM and yuri bazilevs with expertise in the areas of impact damage to aircraft structures and development of novel computational techniques applied to problems exhibiting complex nonlinear behavior and d. M. Hoyt leading a team at NSE composites a small engineering firm composed of industry knowledgeable experts in damage tolerance and residual strength failure prediction NSE composites has significant experience in damage tolerance analyses supporting aircraft certification. This teaming combination is highly complementary where ucsd researchers will work at depth to create new modeling capabilities establish methodologies and provide experimental data while NSE composites will provide real world aircraft engineering expertise and help to focus the research activity on important aspects thereby ensuring that the modeling capabilities to be developed are capable of solving real problems relevant to the aircraft industry. The proposed work will be executed via five tasks 1 impact damage modeling 2 residual strength core model development 3 defining seed damage in residual strength model using non destructive evaluation NDE data 4 defining seed damage using impact damage modeling results and 5 experimental validation and NDE. An extensive body of previously impacted specimens constituting 413 different conditions conducted over an 18 5 person year work effort will be used within this program to provide a vast library of impact scenarios and damage states for guiding and validating impact damage prediction models. New specimens will also be created to validate the models including six large-sized 3 or 4 stringer curved panels that will be residual strength tested after impact. Model and mechanical test data photos and test videos and NDE data will all be shared publicly through the ucsd library's research data curation services available in perpetuity in a manner citable by researchers. Data will be publically posted in continuous real time fashion and thus be available for aiding the validation and development of other current NASA funded projects as well as be available to support the development of future progressive damage analysis tools.