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Some examples of viscoelastic materials are amorphous polymers, semicrystalline polymers, biopolymers, metals at very high temperatures, and bitumen materials. Cracking occurs when the strain is applied quickly and outside of the elastic limit.
Unlike purely elastic materials, viscoelastic materials exhibit both elastic behavior and viscous behavior. In other words, they can store and release energy like an elastic material, but they can also flow and deform like a viscous material.
Polymeric materials, and in particular the thermoplastic ones, are viscoelastic materials. When a viscoelastic material is subjected to a stress, the response is composed by an elastic deformation (which stores energy) and a viscous flow (which dissipates energy).
Viscoelastic materials are unique substances that exhibit both viscous and elastic characteristics when undergoing deformation. This hybrid nature allows them to dissipate energy like a viscous liquid and also recover their shape like an elastic solid.
Viscoelastic materials are used in automobile bumpers, on computer drives to protect from mechanical shock, in helmets (the foam padding inside), in wrestling mats, etc. Viscoelastic materials are also used in shoe insoles to reduce impact transmitted to a person's skeleton.
Some of the properties of viscoelastic materials are their ability to creep, recover, undergo stress relaxation and absorb energy. Some examples of these phenomena are discussed in
Examples of synthetic viscoelastic materials include rubber, a variety of plastics and polymers, and memory foam, which was invented by NASA in the 1960s. Key viscoelastic properties of materials include Crepuscular Behaviour (delayed elasticity), Hysteresis, and Relaxation and Retardation Spectrum.
The term viscoelasticity is a combination of two inherent properties, i.e., viscous and elastic. Characteristics and properties of viscoelastic materials such as polymers and elastomers include loss modulus (E″), storage modulus (E′), and tan δ (ratio of loss to storage modulus).
emistry and microstructure. The concepts and techniques presented here are important for this purpose, but the principal objective of this document is to demonstrate how linear viscoelasticity can be incorporated into the general theory of mechanics of materials, so that structures containing viscoelastic components c.
VISCOELASTIC MATERIALS. Understanding viscoelasticity is pertinent to design applications as di-verse as earplugs, gaskets, computer disks, satellite stability, medical diagnosis, injury prevention, vibration abatement, tire performance, sports, spacecraft, and music.