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There are numerous parameters that affect the handling characteristics of ground vehicles. Among those, lateral and torsional body stiffness plays a major role. Increasing the body stiffness not only improves the handling characteristics, [1] but also other properties like crashworthiness, [6], Noise Vibration & Harshness [NVH], and durability, [2], [3]. But a body with high stiffness, demands a higher weight and cost because of the increased panel thickness required and reinforcement members. Car manufactures try to reduce the vehicle weight to improve the fuel efficiency, because this is one of the primary criteria based on which customers purchase vehicles. In the process of achieving a light weight body, the body stiffness may suffer. As a result of many earlier studies, it is known that increase in stiffness of the vehicle body improves the handling of the vehicle, [2].

In a highly competitive market, one of the major challenges for an automobile designer is to lower the product cost while improving the performance. Therefore, from the vehicle comfort point of view, achieving a good ride, handling and NVH performance, while satisfying the low cost and low weight target needs attention from the concept stage of the development cycle. To achieve this balance, it is important to optimize the static and dynamic stiffness of the vehicle body. This paper focuses on the effect of vehicle body stiffness on the ride, handling and NVH parameters. It also addresses the relation between static and dynamic stiffness of the vehicle. The correlation of the stiffness values with the ride, handling and NVH performance is also studied through various experiments on the actual vehicle

One of the most common NVH refinement areas of a vehicle is the cabin booming noise. The current study discusses the improvement of the low frequency booming noise in the cabin of a small passenger car. The practice of reinforcing experimental evaluation results with the extensive use of computer aided engineering tools in the development process is presented in this paper. The structural changes executed in the vehicle, to reduce noise contribution, are iterated and optimized using simulation and validated using experimental analysis methods like operational modal analysis, linear frequency response functions and actual run-up measurements. Additionally, the interesting variation of the NVH characteristics of a vehicle due to the changeover from a 4-cylinder inline to a 3-cylinder inline powertrain, while inheriting the similar body structure, is discussed in this study.

Structure borne noise is the major source of noise inside the vehicle compartment. Recently the quietness of the occupant cabin has become an important dimension to the quality of product. OEMs are finding it challenging to meet the customer expectations for “Powerful yet quiet” attribute. Several focused studies have been made to reduce the under hood component noise in automobiles. This paper summarizes the optimization of vibro-accoustic sensitivity (VAS) of the engine mounts in passenger car engine. The contribution of each engine mount on the structure-borne noise transfer inside the cabin is studied by conventional FRF and normal mode analysis using Nastran, along with physical testing validation. This paper emphasizes to reduce the structure borne noise with the focus on weight reduction of the body side engine mount.