压气机叶片动应力测量标定试验方法

A method to improve the dynamic stress measurement accuracy for compressor blades was introduced. Dynamic stress calibration tests of the instrumented blades were carried out before assembly of the rotor. Strain gauge sensitivity ratios of the measured strain to the maximum modal strain for each vibration mode of the instrumented blades were acquired. The ratios were helpful in defining strain monitoring limits for the blades during engine tests，which made blade vibration safety monitoring more accurate. Advantages and drawbacks of two calibration methods，direct stress and af strength method（the product of vibration amplitude a multiplies vibration frequency f）， were comparatively analyzed. Based on the direct stress method， stress calibration tests for two compressor blades were carried out. Results showed that the measured gauge sensitivity ratios of the 1# blade for the 1st mode and the 3rd mode were larger than the theoretical ratios with values of 17. 4% and 24% respectively. And the gauge sensitivity ratio differences of the two blades（1# blade and 2# blade）for the 1st vibration mode reached 14. 8%. It proved that calibration tests could improve measured data validation for blade dynamic stress comprehensively.