Study On Distribution Of Flow Field And It's Influence On Performance Of Magnetorheological Impact Absorber Under Impact Load

In order to improve the safety of automobile collision,to protect the driver,the research and development of the buffer device with variable stiffness,damping adjustable and college absorption characteristics has become the research focus of many experts and scholars.Magnetorheological dampers which make magnetorheological materials as circulation medium have the characteristics of adjustable damping force,fast response speed,simple structure,low energy consumption,and has a good application prospect in the field of high speed buffering.With the development of magnetorheological materials and magnetorheological buffering technology,magnetorheological dampers' application in the field of car collision safety has a new direction and possibility,the study of magnetorheological damper in the field of car collision safety has important academic value and practical significance.But there are still some problems in the study of magnetorheological damping device,such as energy absorption way a single,low utilization rate of magnetic field,the lack of generality of cushioning performance evaluation index,the factors influencing cushioning performance are still not clear,etc.In order to define the buffer performance influence factors and provide the theoretical basis for magnetorheological damper performance optimization,internal flow field distribution of magnetorheological damper was analyzed and the influence of flow field distribution on the buffering performance of magnetorheological buffer was clarified,that were based on the material characteristics of magnetorheological rheological cementitious materials and the working principle of magnetorheological buffer device.By analyzing the rheological properties of magnetorheological daub,H-B model was selected to characterize the rheological properties of magnetorheological daub,then mechanical analysis about the distribution of flow field inside the channel was performed,and the influence factors of flow field distribution were clarified.Through finite element simulation,the influence of each factor on the distribution of convective field was further clarified.According to the working principle of the buffer,the dynamic model of the buffer is established.The external impact signal is obtained through experiments and the simulation model is verified and optimized to obtain a reasonable dynamic buffer process.Based on the dynamic simulation results,the effect of flow field distribution on buffer performance was determined.It was found that,the main factors influencing the flow field distribution were external impact velocity(inlet velocity),channel structure parameters and the magnetic field strength.Among the channel structure parameters,the radius of circular pipe channel and the height of circular pipe channel have the most obvious influence on the flow field distribution.Without considering the effects of corrugated pipe,internal flow field distribution has obvious effects on cushioning performance: the smaller the peak velocity,the pressure field distribution is more even,the smaller the peak pressure,the smaller the peak impact heritability,the biggest impact deformation is larger,the smaller the impact cutting rates,and vice versa.