Light Truck Pass-by Noise Modelling with Boundary Elements Method
of the first studies on automobile pass-by and internal noises, using a hybrid
method involving source identification and numerical analysis, achieved through
a partnership between SCS and one of major acoustic materials manufacturers,
a firm which performs analysis and design, and provides solutions for automobile
manufacturers. SCS was charged to perform numerical analysis and the acoustic
and vibration expertise, and to manage the experimental analysis development.
The objective of this study was to improve the acoustic behaviour of a light
The important outcome of this study is that relevant solutions and improvements were investigated with a numerical model (based on the CAD model) of the van, before a prototype was available.
The project was conducted in 2 phases
A complete investigation was conducted on an existing van in order
to validate the hybrid method contained in Rayon Solver (I-deas component) in
which the experimental part consisted of: pass-by noise, engine noise radiation
and internal noise measurements.
The second phase was the acoustic design of the new light truck with
a numerical model, by using the engine source of the existing van (the new engine
was not yet available). Results were then updated when the new engine was characterized.
A proper source model of the engine was derived by using an Inverse Boundary
Element scheme, involving experimental data and a boundary element model of
the engine, defined as a set of prescribed acceleration surfaces. Once the engine
noise model has been derived, the pass-by noise is computed by using the standard
Variational Boundary Element Method.