Difference between 'plastic yielding' & plastic strength?

In summary, the terms "plastic yielding," "plastic yield strength," "plastic strength," and "plastic stress" are all related to stress and strain curves in materials. "Strength" refers to a specific value of stress for a given material, such as yield strength or tensile strength. "Plastic" typically refers to plastic deformation, which is when a material is permanently deformed under high stress. This is in contrast to elastic deformation, where the material returns to its original shape once the stress is removed. For brittle materials like granite, there is no plastic deformation and the material will break suddenly after reaching its elastic limit.
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Atr cheema
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I am going through a literature where the terms like ( 'plastic yielding' , 'plastic yield strength', plastic strength' and 'plastic stress') are regularly used and I am confused. Are they different and if yes then how each term differs from the other? I also want to know relation of plastic strength of a rock (say granite) with pressure. I mean which equation describes this relation?
 
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All of these are based on stress-strain curves. The stress definition is the same as the one for pressure (##\frac{Force}{Area}##), so they have the same unit.

«Strength» is a value of stress representing a property for a given material:
  • Yield strength: Stress at which a material begins to deform plastically when elongated;
  • Tensile strength: Maximum stress that a material can withstand in elongation (syn.: ultimate strength);
  • Compressive strength: Maximum stress that a material can withstand in compression;
  • Shear yield strength: Same as yield strength, but for torsion;
  • Ultimate shear strength: Same as tensile strength, but for torsion.
Saying 'yield stress' or 'yield strength' refer to the same thing, although the last one should be more appropriate.

Although I never really heard anyone use 'plastic' in engineering materials, it should refer to 'plastic deformation' which makes more sense with ductile materials. Ductile materials deform elastically at low stresses, meaning they go back to their original shape once the stress is removed. At higher stresses, they deform plastically, meaning they are permanently deformed, even when the stress is removed. The stress value that separates the two zones is the yield strength.

For brittle materials (like granite), there is no plastic deformation: It deforms elastically until it suddenly breaks.
 
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What is the meaning of "plastic yielding"?

Plastic yielding refers to the point at which a material begins to permanently deform under stress. This means that the material will not return to its original shape once the stress is removed.

What is the definition of plastic strength?

Plastic strength is the maximum stress a material can withstand before it breaks or fractures. This is different from plastic yielding because the material is still able to return to its original shape once the stress is removed.

What factors affect plastic yielding?

Plastic yielding can be affected by the material's composition, temperature, and the amount of stress applied. Different materials have different levels of resistance to plastic yielding, and higher temperatures can make a material more susceptible to yielding.

How is plastic yielding different from elastic deformation?

Elastic deformation is when a material is temporarily deformed under stress but returns to its original shape once the stress is removed. Plastic yielding, on the other hand, results in permanent deformation of the material.

Can plastic yielding be beneficial?

Yes, plastic yielding can be beneficial in certain applications. For example, in metal forming processes, plastic yielding allows for the shaping and bending of metal without causing it to fracture. It can also be useful in materials that need to absorb energy, such as in packaging or cushioning materials.

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