Study Of The Stress-strain Test Method On The Powertrain Of The Automobile

In recent years, with the development of automobile toward the direction of high power and high torque, the problem of NVH seems more and more serious, the research to improve the harshness and safety has become the hotspot. When the engine is powered the vehicle, its torque fluctuation will transmit to the power train, cause alternative torsional shear strain and stress in the power train, seriously influence the safety of the automobile. At present, the methods for strain and stress testing available home and abroad, however, are not suitable for the on line monitoring of the power train. Therefore, the torsional shear strain and stress testing research on the power train has great theoretical value and practical significance.Targeting at the present situation, this dissertation targeted at the vehicle’power train, achieved the research torsional shear strain and stress testing methods:Firstly, thoroughly summarized the methods for strain and stress testing available home and abroad, analyzed the cause of torque fluctuation according to the structure and characteristic of the power train, put forward a torsional shear strain and stress testing method for the power train based on the principle of phase difference, derived the principle algorithm in detail, quantitatively analyzed the factors which affect the measuring accuracy and put forward the relevant improvement measures.Secondly, studied the treatment of torsional shear strain and stress testing signals on the power train, proposed the method of equal space angle sampling, emphasis is placed on the research of signal treatment methods, such as multi-period data average, digital tracking filtering, the distorted point digital filtering and so on. On this basis, the signal treatment methods were simulated on the software LabVIEW and good effect was obtained.Thirdly, created torsional shear strain and stress testing system of automobile’ power train based on the latest virtual instrument technology, designed the hardware part and testing software based on LabVIEW platform.Finally, made testing experiment on the vehicle’power train torsional vibration damping test bed of vehicle’power train, realized the torsional shear strain and stress’ on-line and off-line testing of vehicle’power train and good results were obtained.