Research Of Small Lightweight Electric Vehicle Frontal Crash Response And Structure Optimization

Small lightweight electric vehicle is one of the development directions for automobile industry in our country.Because of its new features in Body-in-white and drive system,when doing research about its crashworthiness,it would be different from traditional vehicle.In this paper,a classic small lightweight electric vehicle model is studied in terms of its crashworthiness,and its body structure is optimized using topology optimization method.First,the influence of mass distribution of occupant and battery on crash response of small lightweight electric vehicle is studied.Because the vehicle weighs only 600 kg,two 75 kg occupants would account for one-quarter of total mass.Thus,their weight would affect the center of gravity of small lightweight EV,thereby affect its crash responds.Meanwhile,the heaviest and largest component in small lightweight EV is the power battery,which in this model,weighs 200 kg.Thus,power battery layout would affect the center of gravity of small lightweight EV,thereby affect its crash responds.In this paper,three different battery layouts are studied,which are T-shape layout on floor,uniform layout on floor and stack-up in the rear battery layout.Finite element model simulationmethod is used for concept researching on topics just mentioned,and get some general features about influence of mass distribution of occupant and battery on crash response of small lightweight electric vehicle.Second,the influence of wheels on frontal crash response of small lightweight electric vehicle is studied.Because of the relatively short length of small lightweight EV,its front crush zone is relatively short.Meanwhile,the size of wheel does not decrease proportionally as vehicle becomes smaller,thus front wheels would account for more space of front crush zone.Moreover,there is no engine in front which would affect deformation of front structures.Therefore,front wheel of small lightweight EV would play more important role during the crash.To study how front wheels influence crash respondsofsmall lightweight EV(600 kg),a Yaris model(1100 kg)is simulated for comparison,which is a small size traditional vehicle and its model can be conveniently accessed by the public.Both energy absorption and load transfer of front wheel is studied.Last but not least,the structure of small lightweight EV is optimized using topology optimization method.Because of the large design field in the front of small lightweight EV,also no similar structure on traditional vehicle for reference,topology optimization method is necessary for structure optimizing.In topology optimization in terms of crashworthiness,there are mainly three types of non-linearity should be considered,which are load non-linearity,material property non-linearity and objection function non-linearity.After comparing two different algorithms,Hybrid Cellular Automata using in LS-TaSC is chose.And after topology optimization,the result is manuallytransferred into finite element model.The model is simulated under frontal crash load,getting better response.