Simulation Research Of A SUV Rollover Dolly Test

The global traffic accident data showed that although the probability of occurrence rollover crash is low,the proportion of death caused by rollover collision is much higher than other forms.Therefore,in order to reduce the casualties in the rolling collision,it is necessary to conduct further research on safety of the tumbling collision.However,vehicle rollovers are still under exploration in China regardless of testing methods or regulations owing to their complicacy.Furthermore it's high cost and long cycle of collision made it difficult to research,however FEA provide an useful method to research rollover test.This paper provides an effective method for finite element modeling of SAEJ2114 according to the test procedure.The specific work is as follows:In this paper,tendencies of rollovers and features of these accidents in the United States were analyzed and summarized from multiple perspectives such as differences in vehicle types,years of production,property losses and mortality based on American Traffic Safety Facts 2014 and NASS-CDS.In the simulation research of this paper,the Ford Explorer finite element vehicle model built by the NCAC was used for verifying the effectiveness of simulating crush deformation on the vehicle roof with the model at first,and two groups of models were constructed for simulating crush resistance of the vehicle roof.The simulation results were benchmarked with C0139 and C0140 tests of the NHTSA's database for testing parts and components.The benchmarking results suggested high consistency between simulations and tests.Based on the benchmarking models,a finite element model was built to simulate the rollover of SAEJ2114 Dolly.After a comparison between the simulation results and No.010412 Dolly rollover test of the NHTSA's collision test database,the model was verified based on dynamic responses of vehicles and structural deformation models of vehicle roofs,confirmed to generally reflect rollover characteristics and tendencies of occupant injuries in J2114 rollover tests.In this paper,occupant injuries of rollovers were studied with THUMS(Total Human Model for Safety)based on benchmarking results in simulating dolly rollover.The biomechanical responses of the THUMS's head,neck,breast and abdomen to rollover were analyzed from the perspective of tissues under the constrained state.In addition,a THUMS was built with safety and constraints,to comparatively analyze occupants' differences in dynamic responses and damages under constrained and unconstrained states.The results show that: for head,seat belts can effectively restrain the head movement of the occupant in the rollover,which can reduce the risk of the third-impact for skull crash and the skull fracture to some extent.For neck,the injury of THUMS human model was not obvious under circumstances of having or without seat belts in the simulation test,which is different from simulation by using Hybrid ? dummy.This may be due to the limited biological simulation of the neck structure of the HybridIII dummy,which cannot restore the dynamic response of human body's neck during rolling,leading to erroneous experimental observation.For thoracic and abdominal injury,the seat belts are unavailable to realize effectively restrict the lateral displacement during fierce rolling occupant in the lateral movement,causing contact between ribs and doors,because the seat belts matching parameters are developed for head-on collision.It may cause fractures of the chest and ribs,and severe lung and spleen damage.Thus,the seat belts are needed to be redesigned if the development focuses on protection system aiming at rolling incidents of passengers.