Research On Multi-objective Optimal Design And Test Of Magnetorheological Impact Absorber For Vehicle Collision

With the increasing of the numbers and the speed of vehicles, road traffic accidentsgrow rapidly in recent years, which result in the enormous loss of life and property.Vehicle buffers, as the first guard of the vehicle safety, play an important role inenhancing the crash safety and reducing the property loss. However, currentlytraditional buffers can only act as an ornament and can not provide any safeguard. Dueto their limited capacities of buffering and the response time, the performance can onlybe achieved under the designed condition. In recent years, a kind of smart materials,magnetorheological (MR) fluid, has been received much attention due to its rapidresponse, reversible viscous variation, broad dynamic range and low power requirement.The dampers based MR fluids have already been applied in many engineering such ascivil earthquake isolation, vehicle suspension vibration control et al. Consequently, anew vehicle buffer based on MR fluids is proposed in order to promote the collisionsafety of the vehicle in this study. Multi-objective optimal algorithm is applied to findthe pareto optimal front of the MR buffer under the high speed impact. The maincontents include the followings.(1) The application background of vehicle buffers has been introduced while theimportance of the investigation into smart vehicle buffers has been discussed. Afterreviewing the literatures about vehicle buffers and MR technology, it has been foundthat traditional buffers can not meet the requirements of vehicle safety. Therefore, it isnecessary to theoretically and experimentally investigate a new kind of vehicle bufferbased on MR fluid.(2) On the basis of modified Bingham plastic model (BPM), the equations of thedamping force and the dynamic range are formulated for the proposed MR buffer. Amulti-objective integrated optimal platform is constructed to find the pareto optimalfront of the design problem of the MR buffer. The optimal platform is integrated on theMatlab and ANSYS softwares. The genetic algorithm is applied to improve thesolutions.(3) After manufacturing the MR buffer based on the above optimal results, thesteady experiment is performed on the electromagnetic vibration platform. The testconditions include the variable amplitude and excited frequency under different inputcurrents. The experimental results are discussed. (4) To investigate the working characteristics under the high speed, a drop towertest facitlity is developed. Four different velocities (four different drop heights) areinvestigated. The experimental results are given and analyzed deeply. The comparisonbetween the theoretical results and the experimental results are also performed. Inaddition, a simple model of the proposed MR buffer is formulated.