inelastilised

Inelastilised is a term used in physics and engineering to describe systems or processes that do not return to their original shape after a deforming force, or in which not all the energy is recovered as kinetic energy. The word is commonly encountered in Estonian-language technical literature as the plural form of inelastiline (inelastic) and is sometimes used in translated texts to refer to inelastic behavior more broadly.

In collisions, inelastic means that some kinetic energy is transformed into other forms of energy, such as heat, sound, or permanent deformation, rather than being conserved as kinetic energy. Momentum is conserved in all collisions, but the distribution of energy changes. A perfectly inelastic collision is a special case in which the colliding objects stick together after impact.

In materials science, inelastic behavior encompasses plastic deformation, where the material undergoes a permanent shape change once the yield point is exceeded. Viscoelastic materials also exhibit inelastic, time-dependent responses, dissipating energy through internal friction. This energy loss is often observable as hysteresis in stress–strain curves. Other forms of inelasticity include creep, where deformation accumulates under sustained load, and damping due to internal friction.

Modeling inelasticity typically involves plasticity theory, with yield criteria and flow rules to describe permanent deformation, as well as viscoelastic or creep models for time-dependent behavior. Experimental indicators include residual strain after unloading, energy dissipation per cycle, and non-recoverable deformation.

Practical applications and considerations of inelastilised include energy absorption in dampers, crash safety design, and any component where permanent deformation or energy dissipation is either desired or must be accounted for in performance specifications. See also elasticity, plasticity, and inelastic collision for related concepts.