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Design decisions based on the virtual simulations leads to reduced number of prototype testing. Demonstrated correlation between the computer simulations and experimental test results is vital for designers to confidently take simulation driven design decisions. For the virtual design evaluation of durability, ride, handling and NVH performance, demonstration of correlation of structural dynamic characteristics is critical. Modal correlation between CAE and physical testing validates the stiffness and mass distribution used in the FE model by correlating mode shape and mode frequency in the desired frequency range. The objective of this study is to arrive at a method for establishing modal correlation between CAE and experimental test for a bare frame and thereby enabling evaluation of design iterations in virtual environment to achieve modal targets.

‘To achieve more from less’ has been the oft-quoted phrase in auto industry for quite some time. This philosophy has many analogies like fuel efficiency, modularity, weight reduction, alternative fuels etc. Of these ‘modularity’ is seen as an effective tool, especially for automotive OEMs catering to a wide portfolio of similar products. This paper discusses the implications of modularization on a passenger bus OEM, by taking the ‘bus super structure’ as a test case. The modularized bus structure is compared with the conventional structure for design strength, safety, weight and more importantly manufacturing flexibility. The challenges faced in each of these aspects are discussed. From the study it was understood that the task of manufacturing body modules and interfaces is complex and it calls for a complete revamp of existing fixtures, material handling equipment and even the prescribed tolerances.

The crankshaft twist is of great concern for heavy duty engines. In order to have a longer B10 life and better NVH characteristics, it is desired to have minimum Torsional vibrations (TV) in the crank shaft. To keep the crankshaft twist in check - TV dampers are used. Aneasier approach is to use a Viscous TV damper which keeps TV below acceptable limit for entire speed range. But this is a very costly approach. In this paper, the design of rubber TV damper for multi-cylinder engine was optimized to have lower TV characteristics. The optimized rubber damper has been developed with AEM - VAMAC™ grade rubber. This material provides advantages of better TV attenuation, higher thermal resistance, oil resistance higher durability and a much longer life than other rubber compositions. Besides rubber profile was also optimized to obtain higher slip torque. The TV amplitudes with existing rubber compound (EPDM -Ethylene Propylene Diene Monomer) were measured in the engine testbed.