High cycle fatigue (HCF) failure is still a major factor negatively impacting safety, operability, and readiness, while at the same time substantially increasing maintenance costs. The HCF failure of compression and turbine system components is still a major contributor to engine failure events experienced in both development and fielded weapon systems. Although much has been done over the last several years to mitigate HCF though the development, validation and transition of new physics-based HCF tools and testing protocols, escapes to the fleet or changes in operational use have resulted in unexpected HCF fractures of fan, compressor and turbine airfoils. Test Devices and Mechanical Solutions will develop state-of-the-art HCF testing and validation methods by developing a blade multi-point measurement system, coupled with a high-temperature, high-order mode excitation system. These technologies will be integrated and validated in a HCF spin pit test system, to the point that at the end of the Phase II SBIR program a customer could use the new HCF test capability to test & validate a full component.
Benefit: A new excitation system will provide the capability of simultaneously exciting multiple engine orders, such that the effects of asymmetry, blade stacking, and closely-spaced, swapped high order can be accurately assessed. A multi-point HCF measurement system will provide the capability measuring the shapes of coupled, high-order HCF modes, in order to improve both HCF models and experimental test capability. The advanced measurement system will provide a high-resolution image of the blade and better correlation/improvement for blade mistuning models. Additional benefits of a multi-point HCF measurement system include: 1) the ability to readily available test capability to reduce HCF risk in development programs, as well as troubleshoot/validate fielded engine issues, 2) maturation of combined displacement/frequency measurement systems for use in fielded PHM applications, and 3 measurement technologies will be scalable to horizontal module and full engine rig tests.
Keywords: PHM, PHM, Radar, UNSHROUDED TURBINE BLADES, Structural Durability, damping, high frequency, high cycle fatigue, HIGH ORDER MODE
