Dynamic properties tests on foam - by gripping test piece between vibrating and backing plates and testing over range of frequencies under conditions concerned

摘要

In a method of determining the dynamic properties of elastic materials, and plastic foams in particular, a test specimen is held at least at one point and subjected to a periodic external excitement; the measurements required are taken in relation to frequency. USE/ADVANTAGE - The method applies to frequencies beyond the resonance frequency of the test piece. It enables the dynamic values to be determined relatively accurately, rapidly and continuously over wide frequency range. The limiting lower frequency is determined against the very low frequency of building vibrations. The upper limiting frequency stems from the rigidity of the mounting or its natural resonance. The test can be performed at approx. actual flow resistances using an uncut test piece larger than the test grip plates. Service pieces of the material can be tested by appropriate size test equipment. The tests can be conducted under various conditions e.g. of temp., relative humidity, vacuum etc. if desired. The method also allows static characteristics to be determined.