Modal testing: Difference between revisions

Revision as of 05:29, 21 April 2022

Revision as of 22:31, 27 May 2022

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[[File:Modal hammer.jpg|thumb|Model hammer with interchangeable tips.]]

An ideal impact to a structure is a perfect impulse, which has an infinitely small duration, causing a constant amplitude in the frequency ___domain; this would result in all [[modes of vibration]] being excited with equal energy. The impact hammer test is designed to replicate this; however, in reality a hammer strike cannot last for an infinitely small duration, but has a known contact time. The duration of the contact time directly influences the frequency content of the [[force]], with a larger contact time causing a smaller range of bandwidth. A [[load cell]] is attached to the end of the hammer to record the force. Impact hammer testing is ideal for small light weight structures; however as the size of the structure increases issues can occur due to a poor [[signal -to -noise ratio]]. This is common on large [[civil engineering]] structures.

== Shaker Modal Testing ==