A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Facts about Vibration

Vibration

Vibrations are closely related to sound, which takes the form of "pressure waves."

Vibration

To start the investigation of the mass-spring-damper we will assume the damping is negligible and that there is no external force applied to the mass (that is, free vibration).

image: i0.wp.com
Vibration

The same waves can induce the vibration of other structures, such as the ear drum.

Vibration

Such vibrations can be caused by imbalances in the rotating parts, uneven friction, the meshing of gear teeth, and so forth.

Vibration

Vibration refers to mechanical oscillations about an equilibrium point.

Vibration

The natural frequency and damping ratio are not only important in free vibration, but also characterize how a system will behave under forced vibration.

Vibration

Written in this form we can see that the vibration at each of the degrees of freedom is just a linear sum of the mode shapes.

Vibration

Vibration testing is accomplished by introducing a forcing function into a structure, usually with some type of shaker.

Vibration

The figure also shows the time domain representation of the resulting vibration.

Vibration

The fundamentals of vibration analysis can be understood by studying the simple mass-spring-damper model.

Vibration

We can view the solution of a vibration problem as an input/output relation—where the force is the input and the output is the vibration.

Vibration

Free vibration occurs when a mechanical system is set off with an initial input and then allowed to vibrate freely.

Vibration

Two typical types of vibration tests performed are random and sine test.

image: img.bhs4.com
Vibration

Most vibration testing is conducted in the vertical axis.

image: buyyou.net
Vibration

The frequency response of the mass-spring-damper therefore outputs a high 7 Hz vibration even though the input force had a relatively low 7 Hz harmonic.

Vibration

Hence, the solution to the problem with a square wave is summing the predicted vibration from each one of the harmonic forces found in the frequency spectrum of the square wave.

Vibration

Note: In this article the step by step mathematical derivations will not be included, but will focus on the major equations and concepts in vibration analysis.

Vibration

The plot of these functions, called "the frequency response of the system," presents one of the most important features in forced vibration.

Vibration

Careful designs are needed to minimize unwanted vibrations.

Vibration

Consequently, one of the major reasons for vibration analysis is to predict when this type of resonance may occur and then to determine what steps to take to prevent it from occurring.

Vibration

The amplitude of the vibration “X” is defined by the following formula.

Vibration

Forced vibration is when an alternating force or motion is applied to a mechanical system.

Vibration

The following are some other points in regards to the forced vibration shown in the frequency response plots.