| Yield point |
The first stress in a material, usually less than the maximum attainable stress, at which an increase in strain occurs without an increase in stress. Only certain metals—those which exhibit a localized, heterogeneous type of transition from elastic to plastic deformation—produce a yield point. If there is a decrease in stress after yielding, a distinction may be made between upper and lower yield points. The load at which a sudden drop in the flow curve occurs is called the upper yield point. The constant load shown on the flow curve is the lower yield point. |
| Yield point (Unit Pa) |
(yield strength, yield stress, Rel, Rel) The stress at which the onset of permanent (plastic) deformation (yielding) occurs in a body under increasing loading. In some materials, a yield-point phenomenon occurs in which stress falls on initial yielding and plastic deformation continues without increase in stress as strain increases further. The yield criterion is the combination of normal and shear stresses which produces yielding under multiaxial loading. |
| Yield strength |
That stress level which will create a permanent deformation of 0.2% or 0.5% or some other small, preselected, amount in a body. Approximately equal to the elastic and proportional limits of the material; a little higher than the proof strength of a bolt. |
| Yield strength |
The stress at which a material exhibits a specified deviation from proportionality of stress and strain. An offset of 0.2% is used for many metals. |
| Yield stress |
The stress level of highly ductile materials, such as structural steels, at which large strains take place without further increase in stress. |
| Yielding |
Evidence of plastic deformation in structural materials. Also known as plastic flow or creep. |
| Yield-point elongation |
During discontinuous yielding, the amount of strain measured from the onset of yielding to the beginning of strain hardening. |
| Young’s modulus |
A term used synonymously with modulus of elasticity. The ratio of tensile or compressive stresses to the resulting strain. |
