Study On Test Technology Of Dual-mass Flywheel Damping System

With the development of the automobile industry, the research of NVH(Noise, Vibration, Harshness) has become the hotspot. The vehicle is a multi-freedom vibration sytem. When the engine is powered vehicle, its torsional vibration will transmit to the power train inevitably, then vibration and noise are formed. It may even lead to serious security issues in a situation of the excitation frequency of torque is equal or close to the inherent frequency. At present, the engine is developing toward super-fast, light, power direction, meanwhile vehicle vibration control is more rigorous than in the past. The emergence of dual-mass flywheel(DMF), to some extent solves the transmission of torsional vibration problem. However, the research on DMF still placed in the start stage in the domestic, there was a big gap between home and abroad not only in the design and manufacture, but also lacked of systematic approach to verify the dual mass flywheel for reducing the effect of torsional vibration transmission. Therefore, the torsional vibration test research on DMF and power train has great theoretical value and practical significance.This dissertation targets DMF's torsional vibration test questions, it includes following related research:1. Engine, DMF and torsional vibration system model is built; 2. Torsional vibration testing methods and technology are researched, testing methods are designed and chosen; 3. Torsional vibration test-bed of DMF are designed and built, Torsional vibration testing system is designed; 4. Test results of torsional vibration test-bed are analyzed.Firstly, according to the shafting of torsional vibration theory, based on researching and analyzing the development of at home and abroad thoroughly and systematically, the authors detailedly analyzed the torsional vibration testing techniques and methods, the data processing and analysis and the testing accuracy and reliability. And then the study content and its significance was illustrated.Secondly, based on analysis of DMF Damping principle, the torsional vibration model of the test-bed was built up. The inherent characteristics of torsional vibration test-bed was analyzed by using modal analysis method. And using ADAMS dynamics simulation software, the damping characteristics about DMF was calculated theoretically.Thirdly, analyzed and compared home and abroad characteristics of torsional vibration test methods, focused on torsional vibration signal acquisition, data processing, discrete signal analysis study. Proposed an order analysis method in which Discrete Fourier Transform is applied to the torsional vibration signal obtained by equal space angle sampling processing(EASP). And simulation analysis of torsional vibration signal was used to verify the correctness of methods.Fourthly, aiming at test method requirements, the design principle of the torsional vibration test and overall solutions were proposed, the components of test-bed were selected. The torsional vibration test system were designed, which was based on virtual instrument technology; Based on LabVIEW8.2 development platform, torsional vibration signal analysis software was developed to realize the torsional vibration data processing and analyzing.Finally, test plan was designed, the experimental data and the theoretical calculation were compared, which could verify the damping effect of DMF on the power train. By comparing with the test results of the ANZT10 torsional vibration testing instrument, it was verified that the testing system had relatively good accuracy. In addition, on the basis of analysis the influence factors of the test accuracy and reliability, it provided reference for the future improvement of torsional vibration test.