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Underhood environment of a passenger vehicle consists of critical components such as heat exchangers, engine, batteries and exhaust system with complex geometries. The exterior styling and the packaging constraints along with the aerodynamic requirements of minimal grill opening areas result in a compact and packed underhood. In such a restricted environment the volume of air flow entering the underhood reduces. The airflow management issues become even more severe in case the underhood environment is located at the rear end of the vehicle, away from the ram air zone available in front of the vehicle, as is the case in the present study. In recent times, a combination of 1D and 3D simulations have gained a high importance to conduct air flow and thermal simulations of vehicle underhood to understand the complex interactions of air flow velocities and temperatures.

This paper describes the analytical methodology for calculating the overbend needed in the door design to counteract the non-linear seal forces acting on the door header. Overbend in the door design will allow the Original Equipment Manufacturer to achieve competitive above belt flushness and gap dimensional targets at static equilibrium of the door header and weatherstrip. This method combines two analytical models of the weatherstrip and the Door-In-White (DIW) to forecast the design overbend necessary to achieve good fit and finish. These models are: 1) Seal compression-load deflection (CLD) models for each angle of attack of the weatherstrip to the door 2) A nonlinear Finite Element Analysis (FEA) model of the trimmed DIW. Bringing these two elements together to model the static equilibrium deflection, this is developed, into overbend requirements. The design synthesis process to meet the overbend design criteria is demonstrated.

The automotive industry faces many competitive challenges including weight and cost reduction to meet CAFE standards. In particular, a thin door panel optimized for weight reduction can cause high manufacturer warranties and durability problems. Traditionally, the assessment of door slam durability is accomplished by tests rather than using computer aided techniques. Many simple CAE techniques such as simple linear static and dynamic analyses have been used to evaluate the door structural integrity. However, the door slam event requires complex analysis due to the transient impact phenomenon. To solve this complex door slam event with a computer based technique is a challenging and interesting problem for CAE engineers. However, a simplified technique has been developed to anticipate the potential durability problem in the door. This technique involves the use of the computer- based finite element method incorporating inertia relief and fatigue life prediction.

The automotive industry faces many competitive challenges including weight and cost reduction to meet CAFE standards. In particular, a non robust door hinge optimized for weight reduction may cause high warranty and durability problems in the field. Many analytical techniques such as optimization and sensitivity analysis have been widely used in a hinging system design. However, none of the techniques include robustness and the design variation in the analysis. This paper presents an application of finite element method coupled with the parameter design using Taguchi's design of experiment. This approach identified the hinge design variables in the pillar-hinge-door system and improved the robustness of vertical rigidity performance.

A design team consisting of engineers from a vehicle platform, body engineering, synthesis & analysis, and suppliers, was formed to accomplish the design, analysis, and prototype manufacturing of a structural instrument panel (IP). The IP design and packaging requirements, material optimization, processing input, and finite element method (FEM) analysis, were combined to develop a feasible design. The structural IP consists mainly of a cross-car beam and a carrier. The structural cross-car beam connects the front body hinge pillars and supports the steering column bracket and HVAC. It provides a restraint surface for the knee bolster and the supplemental inflatable restraint system (SIR), and reacts to barrier and torso impact loads. For the given packaging constraints, a preliminary design was developed to define the structural configuration. Material selection and optimization studies conducted on several design concepts proved to be of great importance in the synthesis approach.

A design synthesis approach is used to design and analyze a Resin-Transfer-Molded (RTM) composite floorpan to meet the product requirements and assess the structural performance. The design envelope is based on packaging constraints representative of a production vehicle to ensure a feasible design intent. Finite element analysis of the composite design is used to guide the design and integrate all of the product performance requirements to achieve a feasible design concept. Issues discussed include the design and analysis, design features, composite material tailoring, prototype fabrication, vehicle build, and product validation. Stiffness, strength and durability tests were performed on the floorpan and the fully trimmed vehicle, and all requirements were met.