Question on material properties???

Question

Do yield stregth and yield stress mean the same thing?

Answer 1

No,

yield strength is value of maximum applied force before material fail.

yield stress is force currently applied onto material.

hope this help..

Answer 2

Stress is the force/unit area at any load; strength is the limit or maximum [tensile, shear, or compressive] stress a material can withstand. Adding "yield" in front makes these terms a bit vague.

Yield stress is a generic term for the force/unit area that causes permanent (plastic) deformation. It often implies the 0.2% offset yield strength. Since yield stress is a limit stress, it is indeed equivalent to a  strength.

Yield strength, in a generic sense, is the limit of the strength of the material when at the yield stress; i.e. same as the yield stress.

So, yes, stress and strength in this context are used interchangeably.

The issue with yield is that most solids deform permanantly (but immeasureably slightly) even under tiny loads. Some measureable limit had to be chosen to represent yield. So, 0.2% offset on the stress strain curve is typically defined as the yield strength for metals.

Don't even try to get into plastics, which have lots of definitions for yield and modulus. They have highly non-ideal structural behavior, and their performance is difficult to model accurately.

If you want to buy metals based on yield, use SMYS, specified minimum yield strength, which is the 0.2% offset stress.

The attached wiki article has these correct definitions, as do most other online sources.

Answer 3

*Yield stregth and yield stress does not mean the same thing.

*The yield strength or yield point of a material is defined in engineering and materials science as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed some fraction of the deformation will be permanent and non-reversible. In the three-dimensional space of the principal stresses (σ1,σ2,σ3), an infinite number of yield points form together a yield surface.

Knowledge of the yield point is vital when designing a component since it generally represents an upper limit to the load that can be applied. It is also important for the control of many materials production techniques such as forging, rolling, or pressing. In structural engineering, this is a soft failure mode which does not normally cause catastrophic failure or ultimate failure unless it accelerates buckling.

*Yield Strength is Indication of maximum stress that can be developed in a material without causing plastic deformation. It is the stress at which a material exhibits a specified permanent deformation and is a practical approximation of elastic limit. Offset yield strength is determined from a Stress-Strain Diagram. It is the stress corresponding to the intersection of the stress-strain curve, and a line parallel to its straight line portion offset by a specified strain. Offset for metals is usually specified as 0.2%, i.e., the intersection of the offset line and the 0-stress axis is at 0.2% strain. Offset for plastics is usually 2%.

Answer 4

no