Vibration Response Analysis Of A Cracked Compressor Blade With Fracture Failure

Fracture failure is a common fault form of compressor blades.It is necessary to analyze the vibration characteristics of the blades with fracture failure.Based on the Ansys Workbench platform and vibration characteristics test system,this paper analyzes the influence of high-order resonance on the vibration characteristics of compressor blades.The main research contents are as follows:(1)Based on the model data of the compressor blade,a 3D model of compressor blade is established by Solid Works,and be divided into two parts,the main body and the block.The finite element model of compressor blade with fracture failure is established,and contact is used to simulate the crack.(2)Based on the Ansys Workbench platform,the natural frequencies and vibration modes of the compressor blades under different working conditions are calculated,and the eighth-order vibration mode and its natural frequency,and the vibration characteristics are obtained through the vibration characteristics test.The first eight natural frequencies of the blade are analyzed;the displacement response of the blade is analyzed under a certain frequency excitation,and it is found that the rotational speed will increase the constant component of the displacement response of the blade The discrete Fourier transform is performed on the displacement response and is found that there are non-linear phenomena,such as the sub-harmonics.(3)The effects of blade speed and crack length on the inherent characteristics of the compressor blade with fracture failure are studied by modal analysis.It is found that the speed has a great effect on the natural frequency of low order resonance,while the crack length has a great effect on the high order resonance frequency.(4)The effects of blade speed and crack length on the vibration characteristics of the compressor blades with corner cracks are studied by transient analysis.It is found that the law of change of the response to displacement of the compressor blades under different crack lengths is basically the same.At the same speed,as the length of the crack increases,the amplitude of the blade’s own travel response will decrease instead.There are supermonics and supermonics in the spectral components of the cracked sheet;the greater the length of the crack,the lower the resonance frequency of the same order and the lower the corresponding displacement response.The contact pressure at the sheet crack is extracted and analyzed,and the breathing effect of the corner crack is evaluated by the contact pressure.The cracks are found to be respiratory cracks in non-speed working condition;cracks are open cracks under constant speed working conditions;cracks in variable speed working condition are affected by the centrifugal force of the blade and gradually change from respiratory cracks to open cracks;As the length increases,the stiffness of the compressor blades continues to decrease,and the breathing cracks are more likely to change into open cracks.