Search Results

The comfort of the passenger inside the vehicle is the primary concern of NVH analysis. The noise sensitivity inside the passenger cabin is studied by performing the acoustic sensitivity analysis. In general, acoustic sensitivity analysis using MSC-Nastran[1] involves coupling the grids on the boundary of the acoustic cavity with the structure grids of the body structure. In MSC-Nastran[1], the coupling between the structure and acoustic cavity can be checked prior to the analysis by using a match grid table and the interface check forces. It has been found that even though the match grid table indicates that all the boundary grids of the acoustic cavity are coupled with the structure grids, the interface check forces is usually quite high. Ideally, the interface checks forces at the boundary should be equal to zero (numerical zero).

This paper presents a methodology for digital design of a bumper system with energy absorber that caters to low velocity impact with a rigid barrier with maximum energy absorption and minimum barrier intrusion with constraint on transmitted rail loading. This gives rise to a conflicting situation and a genetic algorithm based multi-objective optimization software GDOT, developed in-house, is used to come-up with an optimal pareto-front. The technique employed here treats multiple objective functions separately without combining them in any form. A decision-making criterion is subsequently invoked to select the “best” subset of solutions from the obtained non-dominated Pareto optimal solutions.

The automobile industry is seeing an increased need for the application of plastics and their derivatives in various forms such as fiber reinforced plastics, in the design and manufacture of various automotive structural components, to reduce weight, cost and improve fuel efficiency. A lot of effort is being directed at the development of structural plastics, to meet specific automotive requirements such as stiffness, safety, strength, durability and environmental standards and recyclability. This paper presents the many different conceptual cross sections being evaluated during the development of fiber reinforced plastic automotive cross sections. The concepts consists of foam filling of the fiber reinforced plastic cross sections with light weight metal or composite reinforcements. The metal reinforcement is in the form of lightweight metallic tubes. The composite reinforcement is in the form of a carbon fiber bundle.

With the increased motivation for high fuel efficiency, most automotive research and development efforts are being directed at reducing the weight of an automobile without sacrificing the performance related to safety, durability and NVH. Body structure is one of the viable components for weight reduction. Therefore, use of composites, in particular fiber reinforced plastics are seen as a viable alternative to metals to reduce body weight with the lowest penalty on performance and cost. One could expect future vehicles to be a combination of light weight metals and non metals involving a lot of adhesively bonded interfaces. Structural analysis of these bonded joints subjected to mechanical loads is essential. However, since fiber reinforced plastics are subject to temperature effects, an analysis of structure involving such adhesively bonded materials should account not only for mechanical loading effects but also for the thermal loading effects.