Thermoshearographic Methodology for Strain Mapping

To address the Air Force need for a methodology to accurately map strain distributions in hot composite structures, Physical Optics Corporation (POC) proposes to develop a new ThermoShearographic methodology for Strain Mapping (TSSM) based on dynamic monitoring of in-plane strain variation and temperature distribution over the anisotropic specimen surface. Innovative use of a shearographic module with switchable wavelength and its combination with an IR camera for thermal mapping of composite structures meet all requirements in the solicitation. In Phase I, POC will demonstrate the feasibility of the TSSM methodology by assembling and testing the prototype TSSM system that is its core, to enable accuracy in measuring strain distribution on coupon surfaces at moderate mechanical and thermal loads. The results of measurements will be used by Materials Research & Design, Inc. in their prediction model to simulate surface strain versus temperature and loads in coupons of composite materials. The results of modeling will help to understand observed properties of testing coupons. In Phase II, POC plans to fully develop the TSSM methodology with a full-scale TSSM system prototype, allowing accurate mapping of strain distribution and resolution of high spatial strain gradients in a hot, mechanically loaded composite structure. BENEFIT: Beyond quality assurance and quality control of composite structures for military aircraft, where the benefits of the proposed methodology are obvious, it will offer benefits in inspection of composite materials and parts in land-based propulsion and power generation systems, particularly in the automotive and boating industries.