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Q10. Peak of displacement is divided at resonant frequency

Case example

In a piezoelectric analysis, when the frequency characteristics of displacement at phase zero is plotted,

the peak is divided around the resonant frequency (1 in the right figure).

This is because the absolute value of the real part of the displacement is displayed.

Solution

On the [Results] tab, select either

[Magnitude], [X component], [Y component], or [Z component].

Select [Maximum] on the pull-down menu of [Phase].

Theory

Consider a spring-mass system.

If this system generates the loss, the displacement is expressed in the complex value as shown in right figure.

	Displacement(u) is acquired where mass(m) is attached to a spring with spring constant(k) and loss(γ), and force(f) is applied.
	Equation of Motion

	Simple harmonic motion with angular frequency(ω)

	Displacement

Complex displacement

The right figure shows the real and the imaginary parts of the equation above each.

The real part is zero at the resonant frequency.

Thus, the peak of displacement is divided.