There will be thus permanent deformation or permanent set when load is removed; These two points Y 1 and Y 2 are termed as upper and lower yield points respectively. to heavy masticatory load during function. This may include elastic and permanent plastic strain. where ϕ(t) is the time-dependent part of the material modulus, which is termed as Relaxation Function and G ∞ is the elastic modulus at infinite time, that is, the modulus which is due to the recoverable part of the stress. The strain then increases over time. When a material is subjected to constant or repeated load below the failure stress, the mate-rial will eventually fail. The recoverable deformation reflects the fundamental time-dependent behavior of concrete, and the unrecoverable deformation is caused by the accumulation of micro-damage in concrete, Rossi et al. When load is applied on a concrete specimen, shows an instantaneous deformation followed by slow increase of deformation is called concrete creep. The strain usually increases with an ever decreasing strain rate. As mentioned above, the deformation of concrete consists of recoverable and unrecoverable deformation under sustained load. recovery test, that is, to a constant load and to the subsequent removal of that load. Creep is a time-dependent permanent (plastic) deformation under a certain applied load. Creep: It is a deformation of a material due to the constant load for a long period of time. First there is an instantaneous elastic straining, followed by an ever-increasing strain over •It is a time- dependent deformation under a certain applied load. lead or glass), albeit much slower. The stress at the yield point is called … Creep is a time-dependent permanent (plastic) deformation under a certain applied load. Creep is a time-dependent deformation of a material while under an applied load that is below its yield strength. The reliability of metallic microelectromechanical systems (MEMS) depends on time-dependent deformation such as creep. Creep terminates in rupture if steps are not taken to bring to a halt. The Creep and Recovery Test The creep-recovery test involves loading a material at constant stress, holding that stress for some length of time and then removing the load. There are two time-dependent phenomena. It is most often occurs at elevated temperature, but some materials creep at room temperature. •Generally occurs at high temperature (thermal creep), but can also happen at room temperature in certain materials (e.g. Beyond the elastic limit plastic deformation occurs and strains are not totally recoverable. One is fatigue. •As a result, the material undergoes a time dependent increase in length, which could be dangerous while in service. The response of a typical viscoelastic material to this test is show in Fig. 10.1.3. Solution(By Examveda Team) Resilience: The ability of a material to absorb energy under elastic deformation and to recover this energy upon removal of load is termed as resilience.Resilience is indicated by the area under the stress strain curve till the point of elastic limit. Sometimes, σ(t)/γ 0 is termed as relaxation modulus. It leads to what has been termed recovery … This time-dependent response is known as creep. When load is applied on a concrete specimen, shows an instantaneous deformation followed by slow increase of deformation is called concrete creep. • Time-dependent recoverable, that is not widely studied or analyzed, but may become very important at low stresses and under nonsteady conditions, that is, high-temperature service. It first suffers an instantaneous strain upon loading. 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