Investigation and improvment of noise, vibration and harshness(nvh) properties of automotive panels

ABSTRACT INVESTIGATION AND IMPROVEMENT OF NOISE, VIBRATION AND HARSHNESS (NVH) PROPERTIES OF AUTOMOTIVE PANELS by MOHAMMAD AL-ZUBI July 2012 Advisor: Dr. Emmanuel Ayorinde Major: Mechanical Engineering Degree: Doctor of Philosophy The reduction of noise and vibration in and across several components and modules of the automotive, such as the panels, doors, engine covers, seats, and others, is of primary importance. The NVH performance may be a crucial factor in the purchase decisions of numerous buyers. This work investigates through experimental, analytical and computational methods, six groups of sample materials - fabric, foam, honeycomb, monolithic and sandwich, periodic cellular material structures (PCMS), and generally periodic materials, to assess their suitability for maximum containment of noise and vibration. Various architectural forms have also been considered. State-of-the art instrumentation and adequate analytical and computational methods have been utilized. Five major novel accomplishments have been logged in the work. Vibro-acoustic responses of PCMS materials, and newly-constructed generally periodic materials are explored, and some computer procedures are generated. The results give some suggestions for design directions to follow in order to achieve better performances