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F.R. Larson and J. Miller proposed that creep rate could adequately be described by the Arrhenius type equation: r = A ⋅ e − Δ H / ( R ⋅ T ) {\displaystyle r=A\cdot e^{-\Delta H/(R\cdot T)}} Where r is the creep process rate, A is a constant, R is the universal gas constant , T is the absolute temperature , and Δ H {\displaystyle \Delta ...
The phenomenological equation which describes Harper–Dorn creep is = where ρ 0 is dislocation density (constant for Harper–Dorn creep), D v is the diffusivity through the volume of the material, G is the shear modulus and b is the Burgers vector, σ s, and n is the stress exponent which varies between 1 and 3.
The first constitutive equation (constitutive law) was developed by Robert Hooke and is known as Hooke's law.It deals with the case of linear elastic materials.Following this discovery, this type of equation, often called a "stress-strain relation" in this example, but also called a "constitutive assumption" or an "equation of state" was commonly used.
According to van der Waals, the theorem of corresponding states (or principle/law of corresponding states) indicates that all fluids, when compared at the same reduced temperature and reduced pressure, have approximately the same compressibility factor and all deviate from ideal gas behavior to about the same degree. [1] [2]
The main mechanisms of diffusive mass transfer are Nabarro-Herring creep, Coble creep, and pressure solution. Nabarro–herring creep, or volume diffusion , acts at high homologous temperatures and is grain size dependent with the strain-rate inversely proportional to the square of the grain size (creep rate decreases as the grain size increases).
A primary creep stage, also known as transient creep, is the starting stage during which hardening of the material leads to a decrease in the rate of flow which is initially very high. ( 0 ≤ ε ≤ ε 1 ) {\displaystyle (0\leq {\boldsymbol {\varepsilon }}\leq {\boldsymbol {\varepsilon }}_{1})} .
The laws describing the behaviour of gases under fixed pressure, volume, amount of gas, and absolute temperature conditions are called gas laws.The basic gas laws were discovered by the end of the 18th century when scientists found out that relationships between pressure, volume and temperature of a sample of gas could be obtained which would hold to approximation for all gases.
A hyperelastic or Green elastic material [1] is a type of constitutive model for ideally elastic material for which the stress–strain relationship derives from a strain energy density function. The hyperelastic material is a special case of a Cauchy elastic material .