What is tensile strength and what is the standard formula for finding it?

Question

What is tensile strength and what is the standard formula for finding it?

Answer 1

Tensile strenght is measures the amount of stress applied to a material at its breaking point or the point at which it fails. The tensile strength of a material is the point at which a material, under the stress of an applied force, snaps, breaks or can no longer maintain its structural integrity. It is, in other words, the amount of force the material can withstand without breaking.

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We can measure the strenght of specific material by Yield Strength Fy  and ultimate strenght  Fu. Yield means, the material will withstand the applied strength without any deformation or within the elastic limit or if we release the load  the material will regain it original shape or position. The ultimate strenght means the materail start deform with applied load and the deformation would be permanent. If the materail break or snap then that point of applied stress called Breaking point or breaking strenght.

Answer 2

The details in the wiki article are mostly correct, but the contradictory broad statements in the introduction largely range from misleading to wrong.

Tensile stress is the stress in a material in a tensile direction. Strength is a limit condition (i.e. max value). So tensile strength can be any one of many maximum tensile stresses before material failure.

Most commonly, it is used to mean UTS, ultimate tensile strength, which is the maximum engineering stress the material withstands during a tensile test. In this context, "engineering" means based on the original sample area, and corresponds to the peak value on the engineering stress/strain curve you get from a tensile test machine.

UTS is not really calculated, other than from the peak of the curve (Force/area). The next most common tensile strength (for metals) is 0.2% offset yeild strength, which is referred to as the Specified Minimum Yield Strength (SMYS). This strength is also taken off the graph, at the point with 0.2% offset, and calculated as force/area. Polymers can creep extensively at the loads and temperatures at which they are used, so their strengths are a whole separate issue.

For any given metal system (which consists of the alloy, the cold working, and the heat treatment), you generally look either of these (UTS or SMYS) up in a reference, and specify it for purchased materials, typically per a standard specification.

Answer 3

Tensile strength is the stress at which a material fails (breaks)under tension.

It defers from yield strength because the later is the stress where the elastic limit of the material is reached or in other words the deformation when additional force is applied is no longer proportional to the force and the length of the material will no longer return back to its original length when the force is removed.

For a material subjected to pure axial tension, the breaking strength is equal to the force applied to cause the failure divided by the smallest cross-sectional area of the material.

This is normally expressed as;

(1). s = F/A

Where;

s = the breaking strength (stress)

F = the force applied that caused the failure

A = the least cross- sectional area of the material

Materials subjected to bending also incur tension stress on one side and compression on the other side.

The tensile strength of the material subjected to bending is obtained from the formula;

(2). s = Mc/I

Where;

s = the breaking strength

M = the bending moment that caused the failure

c = distance from the neutral axis of the cross- sectional area to the extreme fiber subjected to tension

I = the moment of inertia of the cross-section of the material

Care should however be exercised when using the above flexure formula specially for long beams because when a deflection of about twice the depth of the beam is attained

( which can occur even within the propotional stress-strain curve of the material), the configuration of the beam would have change to that of a parabolic form. In which case, the flexure formula no longer applies because the material would then be in pure tension. The equivalent axial tension force should therefore be calculated first on the basis of a parabola before applying formula (1).

Answer 4

the tensile strength is the ability of the material to withstand deformation from being pulled apart.

different materials yield different tensile strengths.. steel is the material most favored to resist tension.

the standard formula for finding the tensile strength of a material is:stress/strain

Answer 5

Tensile strength of a material is the maximum amount of force/stress that it can withstand and still return to its normal shape. In other words, anything above the tensile strength, means the material will plastically (permanently) deform. Tensile strength has many equations depending on what properties your given. The fastest way to to find a stress-strain graph of the material and its maximum tensile strength is the point on the graph where the line no longer stays linear (straight line).