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Creep behavior can be split into three main stages. In primary, or transient, creep, the strain rate is a function of time. In Class M materials, which include most pure materials, primary strain rate decreases over time. This can be due to increasing dislocation density, or it can be due to evolving grain size. In class A materials, which have ...
Creep is dependent on time so the curve that the machine generates is a time vs. strain graph. The slope of a creep curve is the creep rate dε/dt [ citation needed ] The trend of the curve is an upward slope.
The general equation for power law creep is as follows, [17] where is a dimensionless constant relating shear strain rate and stress, μ is the shear modulus, b is the Burger's vector, k is the Boltzmann constant, T is the temperature, n is the stress exponent, is the applied shear stress, and is the effective diffusion constant.
The classical creep curve represents the evolution of strain as a function of time in a material subjected to uniaxial stress at a constant temperature. The creep test, for instance, is performed by applying a constant force/stress and analyzing the strain response of the system.
Concrete creep is essentially the sagging of concrete over time. Creep and shrinkage of concrete are two physical properties of concrete.The creep of concrete, which originates from the calcium silicate hydrates (C-S-H) in the hardened Portland cement paste (which is the binder of mineral aggregates), is fundamentally different from the creep of metals and polymers.
Creep behavior can be described in three stages: primary, secondary, and tertiary creep. When modeling solder, secondary creep, also called steady state creep (constant strain rate), is often the region of interest for describing solder behavior in electronics. Some models also incorporate primary creep.
Experiments can be made where either the stress or strain is held constant for a certain time. These are called quasi-static, and in this case, anelastic materials exhibit creep, elastic aftereffect, and stress relaxation. In these experiments a stress applied and held constant while the strain is observed as a function of time.
In materials science, Coble creep, a form of diffusion creep, is a mechanism for deformation of crystalline solids. Contrasted with other diffusional creep mechanisms, Coble creep is similar to Nabarro–Herring creep in that it is dominant at lower stress levels and higher temperatures than creep mechanisms utilizing dislocation glide. [1]