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Macroscopic constitutive behaviors of aluminum 5052-H38 honeycombs under dynamic inclined loads with respect to the out-of-plane direction are investigated by experiments. The results of the dynamic crush tests indicate that as the impact velocity increases, the normal crush strength increases and the shear strength remains nearly the same for a fixed ratio of the normal to shear displacement rate. The experimental results suggest that the macroscopic yield surface of the honeycomb specimens as a function of the impact velocity under the given dynamic inclined loads is not governed by the isotropic hardening rule of the classical plasticity theory. As the impact velocity increases, the shape of the macroscopic yield surface changes, or more specifically, the curvature of the yield surface increases near the pure compression state.

The front rail plays a very important role in vehicle crash. Trigger holes are commonly used to control frame crush mode due to their simple manufacturing process and flexibility for late changes in the product development phase. Therefore, a study, including CAE and testing, was conducted on a production front rail to understand the effects of trigger hole shape, size and orientation. The trigger hole location in the front rail also affects crash performance. Therefore, the effect of trigger hole location on front rail crash behavior was studied, and understanding these effects is the main objective of this study. A tapered front rail produced from 1.7 mm thick DP600 steel was used for the trigger hole location investigation. Front rails with different trigger spacing and sizes were tested using VIA sled test facility and the crash progress was simulated using a commercial code RADIOSS. The strain rate, welding and forming effects were incorporated in the front rail modeling.

Vehicle pitch and drop play an important role for occupant neck and head injury at frontal impact. The excessive vehicle header drop, due to vehicle pitch and drop during crash, induces aggressive interaction between occupant head and sun visor/header that causes serious head and neck injuries. For most of body-on-frame vehicles, vehicle pitch and drop have commonly been observed at frontal impact tests. It is because the vehicle body is pulled downward by frame rails, which bend down during crash. Hence, the challenges of frame design are not only to absorb crash energy but also to manage frame deformation for minimizing vehicle pitch and drop. In this paper, the finite element method is used to analyze frame deformation at full frontal impact. To ensure the quality of CAE model, a full vehicle FEA model is correlated to barrier tests. In addition, a study of CAE modeling affecting vehicle header drop is performed.