Predicting the Dynamic Stress Concentration Factor Using the Stress Measuring Method Based on the Infrared Thermography

Structural components subjected to high frequency vibrations, such as those used in vibrating parts of gas turbine engines, are usually required to avoid resonance frequencies. Generally, the operating frequency is designed at more than resonance frequencies. When a vibrating structure starts or stops, the structure has to pass through a resonance frequency, which results in large stress concentration [1]. This paper applies thermography to analyze transient stress variation of a circular holed plate. In experiment, the finite element modal (FEM) analysis of the specimen was performed and the surface temperature measured by infrared camera is calculated to the stress of the nearby hole, based on thermoelastic equation. Stress distributions between 2nd and 3rd vibration mode are investigated with thermography and also dynamic stress concentration factors according to the change of vibration amplitude are estimated at resonance frequency.