Mechanical Oscillator

The mechanical oscillator is used in the task of calculation of forced harmonic oscillations and dynamic studies to set motion parameters of a movable element of the structure (the so-called kinematic disturbance of oscillations). Here, it is assumed that the movement of all the structure elements on which boundary condition “Mechanical Oscillator” is imposed, occurs synchronously in accordance with the harmonic (sine) law. In command “Mechanical Oscillator”, the user sets the parameters defining amplitude of the oscillation, whereas oscillation frequency is set in the dialogue of settings for the calculation, “Forced Harmonic Oscillations,” immediately before the calculation is performed. In numerical terms, the character of movement of the structure element can be set by several ways of equal validity via amplitude of:

•displacement, Xm

•velocity,  Vm=Xm*wf

•acceleration, Am=Xmwf2

•overload, Nm= Xmwf2/g

where  wf  is frequency of forced oscillations, rad/s; and g is free fall acceleration, m/s2.
As is seen, all values except displacement amplitude are secondary and are unanimously expressed through oscillation amplitude and frequency of forced oscillation.  

In the dialogue of the properties concerning this restraint, one should define facets, edges or vertices of the body which moves in accordance with the harmonic law.

The typical procedure for setting the Mechanical Oscillator is as follows:

1.Initiate command ”Mechanical Oscillator” .

2.Select oscillating facets, edges or vertices of the body.

3.Select the type of amplitude: "Amplitude" (displacement), “Velocity,”or “Acceleration”.

4.Select the reference system of coordinates.

5.Set the value of amplitude on X, Y, and Z axis.

6.Set "Phase shift" when necessary.

7.Complete the command.

 

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