| The development of new energy vehicles is the only way for China from a big country to a powerful country."Fourteenth Five-Year" new energy vehicle key strategic objectives are electric,lightweight,intelligent.The strategic planning is centered on electrification and combines lightweight and intelligence with it.The optimization design of the structure of electric vehicle body and battery pack related to it has become the research focus and hotspot in the field of new energy vehicles in the future.Compared with traditional fuel vehicles,electric vehicles cancel the engine,gearbox,transmission mechanism,etc.,and add the battery pack.The body structure of electric vehicles has changed a lot compared with traditional fuel vehicles.At present,there is no unified industry standard for CAE analysis method and evaluation standard of electric vehicle body and battery pack.It is urgent to establish a reasonable and perfect evaluation standard system to guide the collision safety design of electric vehicle body and battery pack.In this paper,the modular modeling idea is introduced into the practical work of modeling,put forward the suitable for pure electric vehicle platform and modular modeling strategy,by using the implicit parametric modeling technology electric cars full parameterized model of CAD/CAE integration and explore the car is high,the wheelbase,span,the change of the front suspension and rear suspension of torsional rigidity,the first-order bending modal,first order torsional modal and front-end yawing modal.Stiffness and modal of the whole body at the same time,the deformation of the side of the vehicle mobile walls collision,side column touch condition analysis,determines the electric car body and battery pack of CAE analysis method and evaluation criterion,set up two crashworthiness condition of simplified model of high precision,and high precision equivalent side impact model based on vehicle with battery pack for a multidisciplinary optimization,in ensuring the basis of various performance indicators achieves the effect of lightweight.The research work and innovative achievements of this paper are mainly reflected in the following aspects:(1)The performance evaluation indexes of electric vehicle body and battery pack were established.In terms of CAE analysis and evaluation of static working conditions,the performance of the body-in-white model without battery pack and the coupled body-in-white model with battery pack in bending stiffness,torsion stiffness and modal conditions were analyzed.By comparing the stiffness curves and modal results of the two models,the evaluation indexes for static working conditions were determined.In the aspect of CAE analysis and evaluation of vehicle crashworthiness,the evaluation indexes of side movable deformable barrier impact and side column impact were determined by analyzing the process of side impact.(2)The high-precision equivalent collision submodel under the vehicle side impact condition is built to solve the contradiction between the vehicle collision simulation accuracy and the calculation time.The high-precision equivalent model of AE-MDB was established according to the steps of momentum change analysis,key parts selection and model counterweight,and the high-precision equivalent model of side column impact was established according to the steps of energy absorption analysis,key parts selection and model counterweight.The comparison between the simplified model and the detailed model shows that the simulation error of the high-precision side impact equivalent model can be controlled within 5%,and the computational efficiency can be improved by 49.2% compared with the original detailed model.(3)Platform and modular modeling strategies for full parameterized body and battery pack of EVs are proposed.The lower body of the pure electric vehicle was divided into front cabin assembly,front floor assembly and rear floor assembly,and the upper body was divided into side enclosure assembly,roof assembly,skylight assembly and glass assembly.The parameterized model of the electric vehicle body was established by using the implicit parameterized modeling software.The results show that the electric platform established in this paper can meet the demand of performance bandwidth and realize the rapid derivation of different models.(4)The method of multidisciplinary collaborative optimization is applied to the design optimization of body and battery pack.In order to ensure the accuracy of the proxy model,different algorithms were used for the proxy models under different working conditions,and a collaborative optimization framework was established for the bending stiffness,torsional stiffness,modal,side removable deformable barrier and side column impact of the body and battery pack.The optimized body in white achieved a weight reduction of 6.5% while maintaining the same performance. |
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