Development And Application Of An Automated Module For Interior Head Impact Simulation

During the traffic accidents, the injury caused by impact between occupant head and vehicle upper interior is most serious, so how to reduce the secondary collision of head interior,and protect the safety of the occupant has been paid more and more attention. NHTSA issued Federal Motor Vehicle Safety Standard(FMVSS) 201 U to examine safety performance of the vehicle interiors with interior head impact test, and it provides the basis for interiors design.The FEM is used to simulate the test process of FMVSS201 U, which can improve the efficiency and shorten the development cycle.It is put forward that the FE model of FMH was established to meet the test criteria by modifing Hybrid â…¢ 50 th Dummy head Model. Firstly, according to the the difference between Hybridâ…¢ Dummy head and FMH, the nose and occipital bone cover of Dummy head were remodeled, and the forehead impact zone of FMH was defined.Then, materials density of each part with internal appropriate mass was used to make the mass, centroid and moment of inertia of FMH meet requirements.Finally the material parameters of skin was gained from the reverse method.To vetify optimization results, the simulation of FMH drop tests was carried out.The results show that the dynamic performance of the head model is good, and the model can be used for interiors head impact test simulation.Based on secondary development technology of Hyper Mesh, an automated module for interior head impact simulation was developed,which realize the flow and automation of simulation and provide users with a friendly, convenient and fast tool. Program was designed using TCL/TK to help automate creating targets with simplifed input,including he identification of key reference point, creation of a section surface and finding a point on the line with given distance. The research of movement and energy changes during interior head impact shows that rotation motion of the head will reduce its injury value. To investigate the relation of approach angles and HIC(d), impact simulations with head at different horizontal and vertical approach angle were carried out. According to the simulation results, horizontal approach angle is perpendicular contact plane, the vertical angle is bigger, then the head injury value is greater. Then the worst condition was determined automatically by programming and FMH was locatde at the target by contact rule. After the completion of the positioning, the program automatically defines the contact parameters, impact initial speed, and the file for running was saved to the specified path.With a car as an example,the automated module was used to mark targets on interiors, posit FMH to each target at the worst condition and output results of targets and position. errors value of the results comparing with business software are lesser. Values of head injury at each target was obtained by interior head impact simulation analysis with LS_DYNA, the measures to improve the interior structure were present for the target where HIC(d) is greater than 1000.