2aEA1. A new methodology of applying measured acceleration and forces or pressures as excitation on powertrain models for noise prediction.

Session: Tuesday Morning, May 14

Time: 8:35

Author: Nickolas Vlahopoulos
Author: Richard D. Stark III
Author: Walter Kargus IV
Location: Automated Anal. Corp., 2805 S. Industrial, Ste. 100, Ann Arbor, MI 48104-6767


Numerical methods can be used to compute the vibration of powertrain systems or components and the corresponding radiated noise. Specifically, the finite-element method can be utilized in computing the structural vibration. The structural response will constitute the boundary conditions for the boundary-element method in computing the radiated noise. In this work a new methodology is presented, it allows a combination of measured accelerations, and forces or pressures, to apply as excitation. The innovative elements of this work are: (i) the methodology utilized in prescribing the acceleration at certain parts of the structure; and (ii) integrating the vibration analysis within the acoustics software and creating a single process for computing the noise. A generic six-cylinder engine model is used as an example to demonstrate the new capabilities. The structural finite-element model is utilized to compute the modal basis of the structure. Acceleration measured at the bearing locations, and pressure loads applied at the cylinder head (simulating combustion) comprise the excitation. The modal basis of the structure, the loads, the structural model, and the acoustic boundary-element model are utilized within the acoustics software in comparing the structural vibration and the corresponding radiated noise.

from ASA 131st Meeting, Indianapolis, May 1996