Noise and vibration performance is an indispensable criterion in vehicle design and validation processes since it significantly affects the marketing image of automotive vehicles. The primary goal of this study is to assess and optimize the acoustic and vibration levels in the interior vehicle cabin. The study demonstrated experimental design to acquire sound and vibration signals using three local compact Perodua cars namely Axia, Myvi and Viva on idle (stationary) and non-stationary (highway, pavement and urban) driving conditions. The measured sounds and vibrations are analyzed to obtain the sound quality and vibration exposure levels in the interior cabin. Apart from this, the study presents a formulation of Noise Isolation Index (NII) based on categorizing the trends of sound quality into interior and exterior noises. The NII is developed, compared and validated for the three tested cars and the results showed that Axia has the highest comfort and thus optimal isolation criterion toward the exterior noises. Besides conducting clustering to compare the interior comfort of Axia, Myvi and Viva, this study developed Genetic Algorithm to further optimize the noise and vibration in the interior vehicle cabin. The results of GA model revealed that the interior noise is influenced by vibration exposure values in the interior vehicle cabin. Overall findings of this study indicate that the comfort level is factually influenced by factors including type of road surface, engine transmissions and vehicle design characteristics.
