| Conceptual design phase determines the performance of the vehicle structure , Concept design phase is very critical to the guarantee of body structure performances when developing new vehicle, the deficiency in this phase are very hard to be repaired in the following phases.Using the method of CAE-driven for body structure design in the conceptual design phase, different projects are analyzed approximately before CAD detailed design, along with construct design target, Quantitative distribution of design target such as Strength stiffness.In the vehicle structure design phase, using the CAE Simplified model can compare different projects quickly according to the target, and find the component characters and the cross-section that meet the material property. Once the size of the main cross-section and the load path are determined, the designers can establish a detailed CAD model easily using conceptual model. This method has greatly reduced the development cycle, improves design efficiency, and also ensures design quality, reduce design cost .appropriately. There are many examples about CAE simplified model aboard, but not too many in our country.Main content of this paper:This paper selects representative Commercial Vehicle Cab as the research object. Commercial Vehicle Cab's frontal Pendulum Crashworthiness model is established based on ECE R29 safety standards using PAM-CRASH software. And Commercial Vehicle Cab's Crashworthiness Simplified model is established based on this detailed model. The author also analyzed the main characteristic and the energy absorption condition of the parts and summarizes the main factors that affect the frontal Pendulum Crashworthiness.The principals of establishing the Crashworthiness Simplified model are set according to the main factors that affect the frontal Pendulum Crashworthiness. The frontal Pendulum Crashworthiness of the vehicle can be reflected effectively and meanwhile the characteristics of other parts are not showed. So the model is simple and accurate.The key technology of the establishing of the model——the extraction of the vehicle body stiffness characteristics. According to the mode of the instability deformation in virtual test, the axis direction cushiness stiffness characteristics and the bending stiffness characteristics are extracted. And also the crushness stiffness characteristics parameter ( FP,Fm,δp,δe) and the bending stiffness characteristics ( M p,θp)are extracted. This solved the problem that the stiffness characteristic is hard to get after the structure is simplified. Meanwhile the reverse course of stiffness characteristics extraction is also the course of using parametric model instructing design the main deformed parts are simulate with BEAM214 material model and SPRING220 model in PAM-CRASH software the parts with small deformation are simulate with BEAM201 material model in PAM-CRASH software .Commercial Vehicle Cab's Crashworthiness Simplified model was established finally.The deformation of the body and the reaction force and pendulum Acceleration are verified and results show that the frontal Pendulum Crashworthiness model has the detailed characteristics and it can reflect the deformation characteristic effectively.According to the main deformation area this paper optimized the frontal Pendulum Crashworthiness model by adjusting the spring and beam element stiffness characteristics. The energy absorption device are designed based on the deformation of the floor crossbeam and the thin wall beam crushness stiffness characteristics. The minimized energy absorption of this device are set according to the members survival space. The stiffness of the device higher than the floor crossbeam stiffness can guarantee the effectiveness of energy absorption and the floor crossbeam can be crushed in order that is the frontal floor crossbeam was crushed but can not exceed design goal. The detail structure of Energy absorbing device was made by Calculation according to the stiffness characteristics. Finally also the effectiveness of the energy absorption device was verified.Significance of this paper is using Commercial Vehicle Cab's Crashworthiness Simplified model in the phase of new products research stiffness characteristics and it'match with other structure design program can be evaluated correctly and quickly by using simplified model. Also it can demand safe performance requirements for detailed model.the vehicle crashworthiness can be well control in design phase. The method of Component FE method can be used for other condition of Parametric model. |
