Cure Terms Glossary

Elastic

An elastic material is one which for which any deformation is completely reversible - i.e. a material which can recover its original shape after an imposed deformation has been removed. Thus the energy of deformation is fully recovered when the material bounces back. An elastic collision is one where kinetic energy is conserved. This is in contrast to a viscous material which yields under load and undergoes permanent flow (and the irreversible conversion of mechanical energy into heat).

Of course there is a limit to the load that any material can bear and still recover elastically. At this limit, the material may either fracture (brittle behaviour) or yield and flow (ductile behaviour). For different polymers, the deformations attainable before this limit is reach vary hugely - e.g. from less than 1% strain for a carbon-fibre composite to several hundred percent for many rubbers. The resistance of a material to such deformation (i.e. its stiffness) is termed the elastic modulus.