The mechanical and acoustical behaviour of some polymer composites

Polymeric ma~erials, such as rubber,composites have gained widespread use in life .plastics and Polymers areexamples of viscoelastic materials,that have some of the characteristics of both viscous liquids and elastic solids.Elastic materials have the capacity of storing mechanical energy with negligible losses.fluid stores no energy.un the other hand, viscous The aim of this study is to investigate thecharacteristics of some polymer materials that can be usedas sound materials for acoustical treatment.New five materials have been produced to investigate their mechanical and acoustical behaviour.are easily produced with low cost.This study contains three steps:-These materialsa- Preperation of new five materials (Polymers).b- Inevestigation of the acoustical properties.c- Investigation of the dynamic mechanical properties.These acoustical properties of the polymer materialshave been investigated:1- The absorption characteristics of each material.2- The improvement of impact sound insulation.3- The noise reduction due to lining the enclosure witheach material.4- The use of these materials as shock absorbers.It was found that perforation of the samples increasesthe absorption characteristics. By increasing the diameterof the holes sound absorption coefficient was greatlyincreased for frequencies higher than 3150 HZ. The hole’sdiameter must not be greater than the material thickness.flaking the viscoelastic materials improves the absorptioncoefficient over all the frequency range,especially at highfrequency range.