Denis Blanchet

dBVibroAcoustics

The need in the automotive industry to understand the physical behavior of trims used in a vehicle is high. The PEM (poro-elastic method) was developed to permit an explicit representation of the trims in the FEM full vehicle models and to give tools to diagnose the effect of the trims and test design changes (porous material property, geometry, et...

Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities. The main physical mechanisms related to noise generation within a turbulent flow and the vibro-acoustic transmission through the vehicle greenhouse is nowadays better understood. Several simulation methods such as CF...

Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities in terms of i) how the convective and acoustic sources terms can be identified, ii) how the interaction between the source terms and the side glass can be described and finally iii) how the transfer path from the sour...

The marine industry has in the past extensively used empirical models to predict transfer functions between source locations and noise sensitive cabins. These empirical methods work well for standard construction types, materials and small number of cabins. Today's tendencies are to use complex construction methods, exotic material such as composit...

There are many applications in which exterior flow over a structure is an important source for interior noise. In order to predict interior "wind noise" it is necessary to model both: (i) the spatial and spectral statistics of the exterior fluctuating surface pressures (across a broad frequency range) and (ii) the way in which these fluctuating sur...

Noise and vibration simulation using classical methods such as Finite Element Method (FEM), Boundary Element Method (BEM) and Statistical Energy Analysis (SEA) are well integrated into standard design processes in the automotive, aerospace and train industry. In the marine industry, simulation starts to occupy a key role in product design as vibro-...

In the automotive industry, the use of beading is widely spread. Beads are primarily used to stiffen the floor and dash panels. The aim is to reduce vibration levels and hopefully at the same time reduce radiated noise. Beading has a positive effect close to the first panel mode's natural frequency however it can have a negative effect at all other...

Experimental and numerical investigations of the fluid-structure interaction as well as the sound, induced by the turbulent flow over different plate structures and radiated to the acoustic far field, are presented. To modify the standard inflow condition that is a fully turbulent boundary layer, two obstacles are placed upstream of the observed pl...

The interior noise levels in trains has been reduced considerably during the last decades. However, the acoustic behavior has nowadays an even more important role among the comfort parameters of high speed trains. The FE-SEA hybrid methodologies raised up during the last years have given a new approach to the problem of the structure borne noise, g...

Vibration and internal pressure pulsation propagation in a scroll compressor were modeled using AutoSEA and SEAM software. It was found that the two programs predict very similar results in terms of total dBA levels for the six design alternatives evaluated under three different excitations. In general, however, AutoSEA tended to predict slightly l...

Engine's vibration propagating through its suspension is often responsible for low frequency noise perceived by vehicle occupants. In the design process and at early stage of development, it is useful to have an efficient way of estimating the properties of an engine suspension since these properties directly dictate the engine's structureborne vib...

The implementation of a combined statistical energy analysis (SEA)/finite element analysis (FEA) was demonstrated by the damping treatments for an automobile. The classical Ross-Kerwin-Ungar (RKU) analysis was employed for the calculation of equivalent properties of composite damping treated vehicle panels. The lower panels of the vehicle Body-In-W...