Map 4D
Realistically modeling noise propagation
of ground transportation systems
Ó Acoustique Clairbois Tisseyre Group


Ville de Herve : maquette de 24 km², 2 autoroutes et une ligne TGV

Main functions - Full 3D modelization - 4D modelization (3D + time) - Noise maps - Optimization of shapes and materials

PRESENTATION

A true pioneer in acoustic predicting software, originating as early as 1982, MAP is the subject of many scientific papers. Its representativity in the area of sound propagation phenomena in open spaces has been constantly tested, and its continuous evolution led to its most recent version, MAP 4D .

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 MAIN FUNCTIONS

 I - Geometric modelization

• Creation of the site model through digitization of the environment (digital ground model), of the structures, installations and housing, possibly using Autocad or MicroStation type data.
• Automatic generation of noise sources (trains, cars, trucks) with unlimited possibilities of traffic differenciation.
• Viewing the model under various angles, zooming, checking the constitution of the elements, viewing sound propagation paths.
• Positioning reception points or surfaces (horizontal, vertical or at a constant height with respect to ground).

II – Mapping the noise

• Evolution in time as a specific vehicle goes past.
• Capability to generate any statistical index regarding the noise of the ways (LA10, LA90, LAeq).
• Display of transitory phenomena such as interactions between vehicles and nearby surfaces.
• Animation of simulated traffics.
• Optimization of protection devices such as absorbing materials, reflecting or absorbing noise barriers, half-coverings and tunnels.
• Optimization of shapes and complex materials.

FULL 3D MODELIZATION

The topography is described by a digital ground model, based on isoaltimetry curves. The buildings are layed out with their own shapes and positions; the most complex structures, such as highway interchanges and tunnels are accurately modelized, taking their influence on noise propagation into account. City of Herve : E40 / E42 highways and high speed train.

4D MODELIZATION(3D + TIME) Time - space phenomena The vehicles are not considered as static points, but as real mobile volumes, with their shapes and directivity characteristics. This makes it possible to accurately study all the spatio-temporal effects, such as interactions between vehicles and nearby surfaces.

NOISE MAP All results can be displayed as noise levels and/or efficiency of the noise control devices in the project. Maps are constant level lines maps, colour maps and even animated maps showing e.g. the noise of a train. Iso-L(t) instantaneous noise map Iso-contours L... Iso-L noise map

OPTIMIZATION OF SHAPES AND MATERIALS MAP 4D is currently the only programme allowing full optimization of noise control devices, by modeling their shapes and their materials, whether homogeneous or not. The optimization of high speed train barriers, or of transparent barriers on road viaducts, denotes a complete mastering of the efficiency / cost / aesthetics compromise of the projected protection.