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The minimum value of creep rate that is commonly applied to alloys is based on two norms: (1) the stress required to produce a creep rate of 0.1%/h × 10 −3 and (2) the stress required to produce a creep rate of 0.1%/h × 10 −4, which takes roughly about 11.5 years. The former standard has widely been used in the component design of turbine ...
An object in the plastic deformation range, however, will first have undergone elastic deformation, which is undone simply be removing the applied force, so the object will return part way to its original shape. Soft thermoplastics have a rather large plastic deformation range as do ductile metals such as copper, silver, and gold.
An idealized uniaxial stress-strain curve showing elastic and plastic deformation regimes for the deformation theory of plasticity. There are several mathematical descriptions of plasticity. [12] One is deformation theory (see e.g. Hooke's law) where the Cauchy stress tensor (of order d-1 in d dimensions) is a function of the strain tensor ...
Because the local strains in the neck are large, necking is often closely associated with yielding, a form of plastic deformation associated with ductile materials, often metals or polymers. [1] Once necking has begun, the neck becomes the exclusive location of yielding in the material, as the reduced area gives the neck the largest local stress .
Rate-dependence in this context means that the deformation of the material depends on the rate at which loads are applied. [1] The inelastic behavior that is the subject of viscoplasticity is plastic deformation which means that the material undergoes unrecoverable deformations when a load level is reached. Rate-dependent plasticity is ...
The deformation process associated with this mechanism is referred to as granular flow. [8] The absence of voids results from solid-state diffusive mass transfer, locally enhanced crystal plastic deformation, or solution and precipitation of a grain boundary fluid. [1] This mechanism operates at a low strain rate produced by neighbor switching ...
The shear rate at the inner wall of a Newtonian fluid flowing within a pipe [2] is ˙ =, where: ˙ is the shear rate, measured in reciprocal seconds; v is the linear fluid velocity; d is the inside diameter of the pipe.
It is an indication of the minimum stress a pipe may experience that will cause plastic (permanent) deformation. The SMYS is required to determine the maximum allowable operating pressure (MAOP) of a pipeline, as determined by Barlow's Formula which is P = (2 * S * T)/(OD * SF), where P is pressure, OD is the pipe’s outside diameter, S is the ...