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In recent years NVH has gained a lot of importance in the commercial vehicle industry as it contributes significantly towards user comfort and also towards the quality perception associated with a vehicle. The in-cabin noise of vehicles is critical towards the comfort and usability for the end user and the sound package installed on the vehicle plays a vital role in determining the levels associated with this attribute, especially the high frequency content. The paper discusses a methodology for optimizing the sound package for performance, cost and mass, for a truck. The approach uses a Statistical Energy Analysis (SEA) based optimization. A virtual SEA model is developed, which is correlated with actual test data. After establishing the correlation, an optimization study is carried out to identify the effectiveness of different materials and material combinations towards in-cabin noise.

Driver's ride comfort is an important characteristic in heavy commercial vehicle cab design. Optimizing the ride behavior for different cab variants and vehicle applications is a challenge for cab design and development engineers. Suspension parameter tuning with physical test is time consuming and costly. Therefore, a lumped parameter quarter car model of suspended cab is developed in MATLAB® tool SimScape which includes cab mass, springs and dampers for predicting ride behavior as per ISO 2631. The study is done for a 25 t rigid truck. The input to the system is displacement at axles and the output is acceleration measured at cab and chassis level. This output is correlated with test data obtained from physical measurements using Power Spectral Density (PSD) curves, bode plots and level cross count. This proved that simple lumped parameter models which use very few input parameters can be effectively employed in analysis of cab ride in initial design phases.

One of the important methods by which vibrations of a body are reduced is by the use of vibration absorbers or tuned absorbers. This technique involves attaching a spring mass system, called absorber system, to the vibrating body (also called primary body). This paper is a case study dealing with a primary system, here a driver seat, to attenuate its response to disturbance. It has high damped natural frequency compared to the base excitation frequency, which was collected from test data. The paper discusses the variations in absorber and primary system damping ratio, mass ratio variation and usage of variable stiffness. Detailed analysis showed instability in the tuned system due to the large gap between the primary body's damped natural frequency, and the target base excitation frequency. In order to address varying target excitation frequency, an adaptive tuned absorber is suggested.