Modal testing: Difference between revisions

Revision as of 11:30, 23 June 2023

Revision as of 21:43, 13 August 2023

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== Impact Hammer Modal Testing ==

[[File:Modal hammer.jpg|thumb|ModelModal impact hammer with interchangeable tips and accompanying temporal and frequency responses]]

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 weightlightweight structures;. howeverHowever, as the size of the structure increases, issues can occur due to a poor [[signal-to-noise ratio]]. , Thiswhich is common on large [[civil engineering]] structures.

== Shaker Modal Testing ==