6 Acoustic Criteria

Back

One of the first steps in the design of a system for noise reduction is to

establish the acoustic criteria for the physical situation. This step is similar

in principle to the determination of the failure mode in mechanical design. If

rupture or breaking of the part constitutes failure, the ultimate strength of

the material is used in the design of the part. The maximum stress to which

the part is subjected is limited to a stress less than the ultimate strength of

the material. There are different failure criteria for different cases. For

example, if the part were subjected to dynamic loading (time-varying stress),

the fatigue strength would be the material property that would be important

in the design of the part. In some cases, excessive deflection may constitute

failure, and stress is not involved in limiting the size of the part.

Similarly, we must determine the ‘‘failure criteria’’ for the specific

acoustic design, so that we may design the system to prevent this ‘‘failure.’’

In acoustic design, as well as in mechanical design, there are several different

criteria for different applications. In some cases, the designer seeks to avoid

permanent hearing loss for workers in an industrial area. In other cases, one

may desire to avoid annoyance and unpleasant reactions from the community

near a plant or other source of noise. Finally, the acoustic designer may

wish to reduce the noise so that the noise does not interfere with the workers’

communication or performance of their assigned tasks. We will examine

some of these acoustic criteria and their applications in this chapter.

Copyright © 2003 Marcel Dekker, Inc.

Навигация