Analysis On Torsional Vibration Characteristic And Failure Of An Aero-Engine Damper

"Safety first, Prevention crucia" is the core of civil aviation safety culture of China, it is also the guiding ideology of maintenance and troubleshooting. Practice has proved that only the use of professional knowledge and equipments to carry out in-depth study of the failure to find the real cause of failure,then we can adopt a scientific and effective preventive measures or improve design to components to ensure flight safety。A crankshaft torsional vibration damper components failure of an Aero-piston engine on a fixed-wing aircraft, resulting in internal engine parts damage and aircraft force-landing accidents which have serious effects on flight safety. It is of great significance and engineering value to study on the torsional vibration characteristics and failure of damperThis paper focuses on an aero-piston engine. The torsional vibration characteristics and failure of damper are studied, the first work of this paper is studying literatures of engine torsional vibration and dynamic damper, while using internal combustion engine dynamics, engine vibration control and related theoretical knowledge, the working principles of dynamic torsional vibration damper are analyzed. Then the actual mapping of the exterior geometry and weight of the crankshaft components is done, a three-dimensional model of the crank shaft is built and its motion simulation is carried out using Pro/Engineer software. Combining with the empirical formula, the inertia and stiffness of crankshaft components are obtained.According to the actual structure of the crankshaft and the principle of equivalent simplification, after considering all the exciting moments and damping, the torsional vibration calculation model is established, the natural frequency of the crankshaft and the response characteristics when subjected to four different exciting moments are calculated using the Matlab software.The torsional vibration data of the engine in the transition conditions are obtained through ground test, and then the crankshaft torsional vibration characteristics are analyzed using the PTVM software, the theoretical calculations and experimental data are compared and analyzed, the results of torsional vibration calculation model can be used in failure analysis.The cause of components fail is fatigue cracks, which related torsional vibration of crankshaft. Investigation found occurrence of torsional vibration conditions in normal flight training. ANSYS stress analysis using the static load applied to the damper components, and found the washer is the weakest component.Combined with the characteristics of crankshaft, causes of damper failure were analyzed. A ground test is designed to verify the damper failure caused by the rapid closing of the throttle. Based on the analysis conclusions, preventive maintenance and operate measures are proposed.