Optical Temperature and Strain Imaging for Turbine Engine Applications

This proposal addresses the need for instrumentation that can resolve strain and temperature distributions around small features of interest on high temperature, metallic and ceramic gas turbine components with curved surfaces. Two parallel optical approaches are outlined; laser speckle metrology for measuring strain, and phosphor thermometry for measuring temperature. The proposed methods are suited for use on both coated and uncoated specimens, and will be designed around thermo-mechanical fatigue test facilities under development elsewhere. The Phase II work will bring several innovations to each of the proposed technologies. One particularly innovative aspect is the prospect of depth resolved lateral strain imaging within and through a ceramic coating. In Phase I the various technical feasibility issues have been addressed, such that the success probability of each procedure can be estimated. BENEFIT: The proposed speckle metrology systems each have significant potential for strain measurement on representative materials and structures encountered in modern high performance aerospace gas turbines. Furthermore, temperature imaging with thermographic phosphors shows the potential to have high accuracy and precision. Therefore, the combined instrumentation should enable the acquisition of thermomechanical fatigue test data in a practical and cost-effective manner that is superior to other, non-optical methods. The proposed instrumentation is sufficiently versatile to be directly applicable to a very broad range of other applied mechanical problems. As a result, a considerable commercial potential exists, and the proposed work provides an ideal opportunity to explore this.