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In the present paper the engineering development of a structural instrument panel (IP) concept made of a Polypropylene (PP) rubber modified compound filled with 15% talc in which the metal cross car beam has been eliminated, is discussed. The design concept consists of three main injection molded shells which are vibration welded to each other to form a stiff structure. The steering column is attached to the BIW and plastic structure by means of a separate column support made of steel, aluminum, magnesium or fiber-reinforced plastic. The concept has been developed for the European market and is therefore not intended to meet the unbelted FMVSS 208 requirements. The total IP assembly has a substantially lower cost and weight than conventional cross car beam based IP structures while meeting all of the performance requirements. The concept development was supported by static and dynamic numerical analyses using well established, widely used FEA codes.

Fully-integrated structural instrument panels (IP) have been in commercial use in passenger cars, light trucks, and sport utility vehicles for some years now. They offer a cost-effective alternative to the more traditional IP construction that utilizes full-size cross car beams to achieve the structural stiffness and energy management required to meet Federal Motor Vehicle Safety Standard (FMVSS) 208 and corporate performance requirements. The natural evolution of interior designs demands an increasing level of integration of the different components in the interior of the vehicle. Therefore, the natural extension of current structural IP technology is to integrate the steering column subassembly, i.e., steering column and column support, and the heat, ventilation, and air conditioning (HVAC) unit into a modular pre-assembled system.

Today's interior systems design engineer has been challenged with providing significantly lighter, simpler and more cost-effective instrument panel (IP) design solutions, while simultaneously meeting rigorous occupant protection and quality standards. These issues provided the motivation behind the fully-integrated structural instrument panel design developed for Chrysler's Dodge Dakota Truck Platform. This total system design approach greatly depends on the stiffness and ductility of the engineering thermoplastic substrate and cross-sectional design for managing the energy of unrestrained occupants during frontal collisions. The structural IP consists of a fully integrated, three-piece monocoque thermoplastic structure that replaces the traditional retainer, air delivery ducts, steel beams and reinforcements typically used in IP designs.

A fully-integrated thermoplastic structural instrument panel (IP) system will be implemented on Chrysler's Dodge Dakota Truck Platform. The structural IP consists of a three-piece monocoque thermoplastic injection molded structure that replaces the traditional retainer, air delivery ducts, steel beams and reinforcements typically used in IP designs. Ribbed thermoplastic bolster systems have been incorporated as part of the energy management system. The structural IP provides the required stiffness to satisfy noise, vibration, and harshness (NVH) quality targets and the necessary strength and rigidity to effectively meet FMVSS No. 208 requirements for managing occupant and passenger air bag (PAB) deployment loading during 48 km/h (30 mph) frontal crashes.

Structural instrument panels are an excellent alternative to traditional constructions since they can provide substantial part consolidation, weight reduction, tool and cost savings, and manufacturing and assembly simplification. In structural panels, the main energy absorbing element for decelerating an unrestrained occupant is the plastic integrated retainer-structural duct. The role of the components in the instrument panel needs to be clearly understood for adequately engineering the system and properly selecting the polymeric material for optimum system performance in the different operating environments. The present paper discusses the performance of the structural instrument panel, the engineering and design requirements, and provides guidelines for selection of materials.