Sine Vibration

February 17, 2016
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Sine vibration is very important to understand when you are doing the vibration testing. Sine vibration is a relationship between acceleration, velocity, and fixed displacement and frequency dependent. When you are specifying or observing sine vibration, you must consider all of them simultaneously. It is impossible to vary any one of these three parameters without affecting another.

The three parameters of acceleration, velocity and displacement in thesine vibration testing are all linear scalar quantities and in that respect, at any given frequency, each has a constant, proportional relationship with the other. Therefore, there will be some changes to other two parameters when one parameter is changed.

However, the constant of proportionality between the three parameters is frequency dependent and therefore not the same at different frequencies. In general, sine vibration testing uses the certain conventions for measurement of vibration levels.

Acceleration is normally specified and measured in its peak sinusoidal value. This is normally expressed in standardized and normalized dimensionless units of its acceleration.

Velocity in sine vibration is specified in peak amplitude as well. Although not often used in vibration testing applications, velocity is of primary concern to those interested in machinery condition monitoring. The normal units of velocity are inches per second in the English system or millimeters per second in the metric system of units.

Furthermore, displacement is sine vibration testing is usually expressed in normal linear dimensions. However, it is measured over the total vibration excursion or peak to peak amplitude. The normal units of displacement are inches for English or millimeters for the metric system of units.

Moreover, Sine Tests By far is the most common type of sine vibration testing. This involves a logarithmic frequency sweep holding a specified acceleration constant at the base of a test article or its mounting bosses on the test fixture. A control feedback accelerometer is mounted in the desired position on the fixture and the level is maintained as the frequency of vibration is swept. This method insures excitation at all frequencies between the sweep end frequencies.

This type of sine vibration testing usually will cycle up and down repetitively between frequency limits for a specified time or number of sweep cycles to ensure that adequate reliability levels are attained. If the testing requires low frequencies, the limitation of the shaker/system available displacement may require lowering the test acceleration.

In this case, you will need some equipment that you need in doing thesine vibration testing. One of the equipment that you need is electro dynamic shakers. These are primarily force generators, the available systems use force output as their primary rating. The maximum required force for any given specification generally will correspond to the portion of the specification having the highest acceleration.

Finally, sine vibration testing is also important to do when you want to test the vibration in the machinery. This will also very helpful for you and your machinery. By doing vibration testing, you will be able to notice if there are some problems in the machinery that you have.

Therefore, you have to consider of doing the sine vibration testing toward your machinery.

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