Search Results

Structures with multiple materials have now become one of the perceived necessities for automotive industry to address vehicle design requirements such as light-weight, safety, and cost. The objective of this study is to develop a design methodology for multi-material structures accountable for vehicle crash durability. The heuristic topology synthesis approach of Hybrid Cellular Automaton (HCA) framework is implemented to generate multi-material structures with the constraint on the volume fraction of the final design. The HCA framework is integrated with ordered-SIMP (solid isotropic material with penalization) interpolation, artificial material library, as well as statistical analysis of material distribution data to ensure a smooth transition between multiple practical materials during the topology synthesis.

This paper introduces a design methodology to tailor the acceleration and displacement responses of a vehicle structure subjected to a dynamic crushing load. The proposed approach is an extension of the hybrid cellular automaton (HCA) method, through which the internal energy density is uniformly distributed within the structure. The proposed approach, referred here to as an extended HCA (xHCA) method, receives the suitable combinations of volume fraction and a finite element meta-parameter for which the algorithm synthesizes the load paths that allow the desired crash response. Lower meta-parameter values lead designs obtained by traditional optimizers, while larger values lead to designs obtained by the HCA method. Simultaneous implementation of multiple values of meta-parameters is presented here as a further development of xHCA method.

Among the most important finishing structures of a vehicle interior, the door trim panels reduce external noises, present ergonomic concepts generating comfort, improve appearance, and provide objects storage, knobs and buttons. The panels usually composed of several molded parts (trim, armrest, etc.) connected to each other also have structural function as support closing loads, protect occupants of door internal mechanisms, energy absorption in side impacts and resist misuse conditions. Therefore, these trims usually made of polymeric materials must to present good structural integrity, demanding appropriate connections between components to have good load distribution. The connections between parts can be made using bolts, interference fits (like self-locking), welding tubular plastic towers (heat stakes), or clips (such as snap fits) and last two are the most common due to be cheap and with good retention.

A previously developed finite element human head/cervical spine model was further enhanced to include the major muscles in the neck. The head/cervical spine model consists of the skull, C1-C7, disks, facets, and all the ligaments in this region. The vertebral bodies are simulated by deformable bodies and the soft tissues in the cervical spine are modeled by nonlinear anisotropic viscoelastic material. The motion segments in the cervical spine model were validated against three-dimensional cadaver test data reported in the literature. To simulate the passive and active muscle properties, the classical Hill muscle model was implemented in the LS-DYNA code and model parameters were based on measurements of cadaver neck musculature. The head/neck model was used to simulate a human volunteer flexion whiplash test reported in the literature. Simulation results showed that the neck muscle contraction and relaxation activities had a significant effect on the head/neck motion.