Vibro-acoustic analysis of a heavy duty truck cabin

Abstract

Automotive manufacturers invest a lot of effort and money to enhance the vibro-acoustic performance of their products. In a complex dynamic system such as a truck cabin, the enhancement effort may be very difficult and time-consuming if only the 'trial and error' method is used without prior knowledge about the noise contributors. The purpose of this paper is to identify the most influential noise radiating panel in a passenger cabin compartment of a heavy duty truck. The noise inside the vehicle cabin originates from various sources and travels through many pathways. The first step of sound quality refinement is to find the pathways and corresponding operational internal forces. Operational acceleration responses and frequency response functions (FRFs) are measured on a prototype truck to determine the excitation forces while engine is running in operational conditions. Once these internal forces are identified using the experimental force identification (FI) technique, they are utilized to predict the total sound pressure level inside the cabin and also perform the panel acoustic contribution analysis (PACA) to determine the most problematic panel of the cabin. A coupled vibro-acoustic finite element model (FEM) is used to predict the sound pressure level inside the cabin. Sound pressure levels at the driver's and passenger's right and left ears are determined numerically for excitation coming from the cabin mounts ranging between 20-200 Hz. When the most noise radiating panel is identified, it can be redesigned to improve the sound pressure level inside the cabin.