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Vibration Analysis Cat I Practice Question Q 45

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Another practice question for vibration analysis suitable for Cat I and II certifications. This question is taken from "Principles of Vibration" ISBN-13: 978-164415006-1.

For more details about the booklet or the series, visit the Amazon webpage ISO Vibration Analysis Certification Exam: CAT I PREP I Series.

Though the series is originally designed for Cat I, many students and instructors found it useful for Cat II and III.

Regards- Ali M. Al-Shurafa

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Example question for Cat I Vibration Certification Exam
Tags: vibration analysis cat II, vibration analysis training, sample test, certification exam, ISO 18436, practice questions, vibration analysis level 2, Certified Analayst

Hi,

hereβs a good visual of exactly how to find the period or frequency of any graph.

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Jake,

Thanks for the chart. I've comments that might be useful for some readers.

There is a fundamental difference between the two waveforms (in Jake's post) which is physics. To explain this, let us use a third illustration.

Jake's upper plot is the amplitude (elevation of a point of the string) in the y-axis versus the location of points (examples are A, B, C, etc) along the length of the string on the x-axis. So here we look at the entire string as its points positioned up and down at a fixed point of time. This presentation is a sort of operating deflection shape (ODS).

Now, focus only on Point A, for example, and let the string wave continuously with time. If I trace the elevation of Point A (amplitude) over a time window, the second plot in Jake's post is generated. This plot itself does not let us anything about the location of the measurement point on the string. This data presentation is a typical vibration signal we know as a waveform from which we can find a period in time units.

So, if I have only a string plot without information about time, can I find the period?

Regards- Ali M. Al-Shurafa

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