Research On The Torsional Vibration Test System For Rotary Machinery Shaft Based On Virtual Instrument

Torsional vibration monitoring plays an important role in the research field of rotating machinery. It is highly destructive especially for large rotating machinery, it could not only affect machines'running stability, but also easily cause fatigue fracture and structure loose and even serious production accidents. With the development of maximization and hi-speed operation of the rotating machinery, unit shaft system becomes more and more complex, making torsional vibration problems become increasingly prominent. However, up to now, torsional vibration measurement technology is still immature, there are problems in most of the measuring instruments in practical application at present, such as complex structures, limited analysis capabilities, higher require for test conditions, etc., result that it's difficult to improve the test accuracy and test efficiency, and thus to apply advanced technology to develop new type of torsional vibration test system is necessary.The torsional vibration test system developed by virtual instrument technology in this paper gives full play to the functions of computer in the aspects of numerical calculation and graphics processing, etc. can accomplish the auto-test for speed, torsional vibration, strain and so on with one computer, which reduces the test-cost, improves both development efficiency and test efficiency, enforces the system flexibility and facilitates the experiments. Results show that the new test system simplifies the operation, and has friendly interface, can implement torsional vibration signal on-line monitoring, data storage and replay, real-time test and analysis and so on, help to improve the level of system automation.The main contents of this paper arranged as follows:(1) Through analyzing the research status of torsional vibration test system at home and abroad, to find out the problems exist in traditional test equipments, and then proposed applying virtual instrument technology to develop new type of torsional vibration test system;(2) According to the principles of torsional vibration, this paper has analyzed torsional vibration state of the rotating machinery shaft, and achieved modeling and simulation and theoretical calculation of torsional vibration characteristics for the measured shaft;(3) Based on the principles of torsional vibration test, this paper has studied methods for torsional vibration signal acquisition, extraction, processing and analysis, and designed the overall program according to the test requirements, and completed the user interface and the hardware and software modules design;(4) This paper takes the large rotating machinery test platform as the experimental background, combined with ATI2000 series of torsional vibration acceleration sensor to measure the torsional vibration of the actual rotating machine shaft, and then compare the experimental data with the oretical calculation results.Experimental results show that the system can realize the wide frequency bandwith, wide speed, multi-channel simultaneous measuring and online analysis and other functions for shaft torsional vibration test, and the operation is easy as well as flexible, providing the theoretical and technical support for testing and studying torsional vibration of large rotary machine and achieving torsional vibration on-line monitoring, fault diagnosis and so on.