Research On The Dynamic Characteristics And The Application In Car Interior Noise Control Of Composite Constraints Damping Structure

The nervousness, irritability and fatigue reaction of the occupants which directlyaffects the riding comfort and driving safety often are caused by the vibration andnoise of the vehicle. The NVH performance is a key index of a vehicle. Improving thevehicle noise has become an important topic in automobile design. Because of goodeffect, low cost and short development cycle, the vibration and noise reductiontechnology based on the thin-wall damping optimization is widely used in the carnoise reduction. There is a lot of study on the dynamic characteristics of structuredamping and noise reduction application. And when the damping structure is appliedin the interior noise reduction, the following several points are worth discussing: thedamping structure modeling method considering the properties of damping materialparameters change along with the temperature or frequency, the main factorsinfluencing the vibration and acoustic radiation characteristics of the dampingstructure, the application method of damping structure in the car noise controlling etc.Based on the issues discussed above, the modeling method of constraineddamping structure was stressfully researched in the paper, the main factorsinfluencing the vibration and acoustic radiation characteristics of the dampingstructure and the car interior noise control method based on panel dampingoptimization.The main research content are as follows:Based on the relative theory of mechanical properties of the damping materials,the factors determining the damping dissipation energy and the properties of thedamping material parameters changed along with the temperature or frequency isdiscussed in the paper. Then the modeling method of the constrained dampingstructure considering the property that the damping material parameters changedalong with the frequency is researched. Based on the application combined withMATLAB and ANSYS, the calculation results showed that this method has higherprecision than that based on the traditional strain energy. Combined with simulationand experimental methods, the influence factors of vibration/constrained dampingstructure is researched. The results shows: the vibration and acoustic radiationcharacteristics and the total mass of the structure is affected by the thickness of thebased and damping layer and distribution of the damping panel influencesA passenger car’s body-in-white, the cavity inside and the vehicle acoustic-structural coupled model is established. The low modal characteristics of thebody-in-white and the cavity inside are analyzed. Based on the analysis of noisetransfer function, the panels’ contribution and the modal strain energy distribution,the driver’s ear side noise response, the every panels’ contribution under peak and theplate position of constrained damping are researched in the paper.The experimentaldesign and response surface method and GA are applied in optima parameters of thethickness of the based and damping layer. The vibration and acoustic radiationcharacteristics of the board are improved. Finally, the noise response peak value ofthe reference pot is reduced about2dB.In all, the vibration and acoustic radiation characteristics and interior noisereduction application of the composited damping structure is researched through thetheoretical analysis, numerical simulation and experimental methods. The means maybe of a certain reference value in-depth study on the damping optimization.