Viscoelastiset

Viscoelastiset, in materials science often translated as viscoelastic, refer to substances that exhibit both viscous flow and elastic storage of energy when deformed. Their response depends on the rate and duration of loading, as well as temperature and history, reflecting molecular mobility and network structure.

Common models combine elastic springs and viscous dashpots: Maxwell, Kelvin–Voigt, and the Standard Linear Solid. Real materials often show a mix of behaviors and nonlinearity, especially at large strains.

They display creep under constant stress and stress relaxation under constant strain. Oscillatory loading yields a storage modulus G' and a loss modulus G''; the ratio tan delta indicates damping. Both moduli vary with frequency and temperature, necessitating temperature-time superposition in many applications.

Representative examples include polymers, rubbers, gels, and biological tissues, as well as foams, asphalt, and certain soils. Practical uses include damping and vibration control, seals and gaskets, cushioning, medical devices, and tissue engineering scaffolds.

Measured with rheometers or dynamic mechanical analyzers, viscoelastiset require characterization of creep, relaxation, and dynamic moduli to describe material performance under service conditions.

Limitations include nonlinear viscoelasticity at large strains, anisotropy, and pronounced dependence on loading history and temperature, which can complicate modeling and design.