NVH Characteristics Analysis And Correction Of Light-rail Vehicle's Wheels

Noise disturbance is always one of the main problems in city railway traffic development, especially the wheel rail noise, as its forming mechanism is very complex and difficult to control. It is generally believed that since the wheel vibration radiant noise is the main source in the wheel rail noise, the reduction of wheel vibration and noise is therefore considered to be one of the most fundamental measures to reduce the noise of running train.The research of light-rail wheels noises should be investigated from their NVH characteristics. NVH is referred to noise, vibration and harshness, which are inseparable in vehicle and machinery and are often put together to be studied. And it should be focused on the frequency characteristics analysis and their correction. Based on the hammer tests and frequency response analysis, the NVH characteristics of wheel or wheelset were discussed in this paper under the particular constraint of wheel rail contact friction. Also the low frequency modal vibration should be suppressed effectively by wheel rail dry friction; meanwhile the main excitation of wheel rail high-order structural modal oscillation is wheel rail roughness. From the viewpoint of suppressing high-order modal vibration, the strategy of damping ring constraint was therefore proposed based on the sensitive local response surface recognition.Based on the wheelset hammers test in some railway vehicle factory, the combined method of vehicle multi-body dynamics and structure dynamics is applied in this paper. First for the flexible wheel, the NVH characteristics of wheel and their influence of wheel rail contact friction constraints were found out, and the stable-correcting effectiveness of the damping ring to the high-order modal vibration of rims is validated. Second for the flexible wheelset, under the excitation of track irregularity and roughness, the frequency response characteristics were analyzed, consequently the strategy of damping ring constraint, which can reduce wheel noise was determined. By comparing the test and simulation investigations, it can be drawn the conclusion that the high-order modal response of rim is the primary NVH characteristics of light-rail wheel, the main excitation sources of these high-order modal vibrations come from rail roughness. The damping ring constraint, which is linked inside on the rim was proved to have an ideal effect on the stability of these high-order modal vibrations, for example the noise reduction wheel presented in this paper and wheel rim brake and so on, which should all have considerably effect on noise reduction.