Research On Optimization Method Of Damping Material Laying Based On Vehicle Noise Reduction

With the development of the automobile industry,the appearance and performance of cars have been constantly improved.Driving safety has been continuously strengthened.Increasingly importance has been attached to ride comfort of the car.The car’s vibration and noise level is an important measure of vehicle comfort indicators.The NVH performance requirements have been put forward by domestic and foreign laws.Because the vibration of thin-walled parts is the main source of low-frequency noise in the car,the vibration of thin-walled parts analysis and reduction is particularly important.The damping coefficient can be effectively improved by laying the damping material on the thin-walled parts.It can effectively improve the car’s vibration and noise conditions.And it has a wide range of noise reduction and low cost advantages.Because panels of the auto-body are complex and have a large quantity,the location and thickness of the damping material can only be determined empirically.There is a certain blindness and it is not effective damping noise reduction effect.Due to the complexity of the auto-body system,It brings unnecessary time and economic costs.In this study,a simple auto-body device was designed.And the damping material layout optimization method was studied in the simple auto-body device.A finite element model and a sound-solid coupling model of a simple vehicle body are established.The vibration and sound field inside the vehicle body are analyzed.Multiple peak frequencies in the low frequency range are focused on.Based on the panel contribution analysis method,the contribution of sound pressure of each panel to every peak frequency is analyzed.And each panel is divided into positive panel,neutral panel and negative panel according to the contribution degree.The positive panel will be laied damping material on.The damping material is arranged on the panel which has great contribution to the sound field in the vehicle.The thickness of the damping material on these plates is taken as variables.The sound pressure level at peak frequencies inside the simple vehicle device is taken as constraints.The mass of damping material inside the auto-body is taken as the target.The thickness of the damping material inside the vehicle interior is optimized.First of all,DOE(Design of Experiment)is taken by using the optimal Latin hypercube sampling technique.Eighty design samples and twenty verification samples were extracted.A Kriging approximation model is established based on it.And an improved particle swarm optimization algorithm is used to optimize the laying thickness of damping material.The result shows that the weight loss of damping material is 56.6%.And the validity of the optimization method is verified in a simple body device.Finally,the finite element model and the acoustic-solid coupling finite element model of a domestic sedan are established.The damping material arrangement on the white auto-body floor and the roof was taken as the research object.The panel contribution analysis and improved particle swarm optimization algorithm are used to determine the location of damping materials and optimize the laying thickness.The proposed optimization method is applied to the actual auto-body finite element model to verify the feasibility of the proposed optimization method.