تست غیرمخرب تیغه کمپرسور با ارتعاش سنج مبتنی بر اثر دوپلر

Vibration of compressor blades is one of the main causes of high-cycle fatigue and premature failure in turbomachinery. The use of contact sensors such as accelerometers introduces added-mass effects that can shift the estimated natural frequencies; therefore, non-contact measurement techniques are of particular importance. In this study, the natural frequencies and vibration modes of a compressor blade with an airfoil geometry and cantilever boundary condition are identified using sine-sweep excitation from an electromagnetic shaker and non-contact velocity measurement via a Laser Doppler Vibrometer (LDV). The vibration response of the blade was recorded at multiple points, and the velocity–acceleration Frequency Response Function (FRF) was computed. By analyzing FRF peaks and employing the 3-dB bandwidth method, the natural frequencies and modal damping ratios were extracted, and the corresponding bending and torsional modes were identified. The experimental results show good agreement with the expected behavior of healthy compressor blades and demonstrate that the proposed LDV-based protocol, free from added-mass effects and with high repeatability, enables accurate modal identification suitable for structural health monitoring applications.