Cocured materials damp vibration in composite structures

摘要

Vibration occurs in any structure that moves or has moving parts. The effects of vibration range from minor annoyance, such as noise in an automobile, to significant damage to the structure or its contents. The simplest way to design around vibration problems is to make the structure more rugged so that it can withstand the vibration without damage. This approach, however, always adds weight to the structure and often cannot be applied to certain delicate instruments or other sensitive payloads. For example, while it is possible to build an electronics package that can survive the vibration environment of a space launch vehicle, designing a mirror that can withstand the same conditions is a much greater challenge. An alternative approach is to suppress the vibration, reducing its magnitude and thereby minimizing its effects. CSA Engineering (CSA, Mountain View, Calif., U.S.A.) specializes in designing and building vibration suppression systems for aerospace and industrial applications. Conor Johnson, president of CSA and a principal engineer, explains that the company uses two main approaches to vibration suppression: isolation and damping. Neither completely eliminates vibration, but both reduce the vibration at frequencies where the structure is most susceptible to damage. Isolation is mainly used to counteract higher frequency vibrations. Special mounts are installed, which prevent the vibration from moving across certain parts of the structure, either isolating individual components, such as instruments, or isolating a vibration source, such as a motor or pump.