This section discusses the applicable scope and methods of acoustic analysis, as well as current problems and needs in the area of acoustic analysis.
The applicable scope of acoustic analysis includes the following fields of design development and analysis.
|Automobile industry||Vehicle interior noise analysis|
|Aerospace industry||Sound radiated from engine|
|Shipbuilding industry||Acoustic analysis under water|
|Audio/home appliance industry||Noise analysis from home appliances|
|Construction/civil engineering industry||Sound insulation wall, concert hall|
There has been growing demand for noise control and reduced development time and costs in these design and development sectors, leading to increased needs and requests for numerical simulation to meet such demand.
There are various methods according to the technique for modeling behavior related to sound and vibrations.
The element size determining the number of elements and nodes is defined by the wavelength of the upper limit frequency in the analysis. Generally, FEM and BEM require element sizes dividing one wavelength into six.
The boundary element method (BEM) discretizes the boundary of the field subject to analysis into a finite number of elements in order to calculate the physical quantity at any point in the field. BEM is therefore effective for analysis of the following subjects:
Compared to FEM, BEM has the advantage of easy element discretization, which is required for analysis, because the BEM method models only the boundary of models; whereas there is a need to calculate the relation between a specific point on the discretized model and all elements in BEM because it generates the general matrix.
With conventional BEM, only up to 11,000 elements could be handled in a general PC environment (1 CPU, 2-GB memory), limiting the scope of application to small models and low-frequency ranges.
Over the recent years, there have been the following requests from many acoustic-analysis engineers.