Question

Describe stress strain relationship for a loaded steel wire and hence explain the terms elastic limit,permanent set,yield point and tensile strength

Answer 1

Explanation:

• Stress is the force applied by a system on an object upon the area in contact between the system and the object. The SI unit of stress is similar to that of Pressure that is $N/m^{2}$.

                                       $Stress=\frac{Force}{Area}$

• Strain is the ratio of change in dimension of the object with respect to the original dimensions of the object. Since, it is the ratio of similar quantities, strain is a dimensionless quantity.

         Let, x be a quantity such as height or volume then,

                                       $Strain=\frac{dx}{x}$

• Young's modulus gives the relation between Stress and strain. The ratio of stress and strain is called as the young's modulus of the object

                       $Young's$ $modulus$ $=\frac{Stress}{Strain}$

• Suppose, on a rubber band of length $l$, a longitudinal force is applied subject to the area of rubber in contact. This will be the longitudinal stress on the rubber band.
• On application of this force, initially the rubber will elongate. This elongation will continue only until a certain point $(dl)$ from which, if the rubber band be released, it will regain its original length $l$.
• This elongation, after which the stress removed from the object, the object regains its original length is called as the elastic limit of the object.
• If, at a point during elongation, the object is not able to regain its original shape, then, that situation shall be called as the permanent set of the object.
• Let us for reference, consider a non elastic object on which stress is applied due to which strain is produced in the object. After some time, when the object is no longer able to bear more stress and start loosing its properties and yield under the stress, we say that the yield point of the object is reached.
• Once the yield point is reached, even a small amount of force applied on the object results in a larger value of strain produced.
• To avoid yielding under the stress, the stress applied on an object should be close to the elastic limit and should not reach the fracture point from which the object starts losing its properties and break under the force. This is the tensile strength of the object.

Answer 2

Explanation:

Explanation:

Stress is the force applied by a system on an object upon the area in contact between the system and the object. The SI unit of stress is similar to that of Pressure that is N/m^{2}N/m2 .

                                       Stress=\frac{Force}{Area}Stress=AreaForce

Strain is the ratio of change in dimension of the object with respect to the original dimensions of the object. Since, it is the ratio of similar quantities, strain is a dimensionless quantity.

         Let, x be a quantity such as height or volume then,

                                       Strain=\frac{dx}{x}Strain=xdx

Young's modulus gives the relation between Stress and strain. The ratio of stress and strain is called as the young's modulus of the object

                       Young'sYoung′s modulusmodulus =\frac{Stress}{Strain}=StrainStress

Suppose, on a rubber band of length ll , a longitudinal force is applied subject to the area of rubber in contact. This will be the longitudinal stress on the rubber band.On application of this force, initially the rubber will elongate. This elongation will continue only until a certain point (dl)(dl) from which, if the rubber band be released, it will regain its original length ll .This elongation, after which the stress removed from the object, the object regains its original length is called as the elastic limit of the object.If, at a point during elongation, the object is not able to regain its original shape, then, that situation shall be called as the permanent set of the object.Let us for reference, consider a non elastic object on which stress is applied due to which strain is produced in the object. After some time, when the object is no longer able to bear more stress and start loosing its properties and yield under the stress, we say that the yield point of the object is reached.Once the yield point is reached, even a small amount of force applied on the object results in a larger value of strain produced.To avoid yielding under the stress, the stress applied on an object should be close to the elastic limit and should not reach the fracture point from which the object starts losing its properties and break under the force. This is the tensile strength of the object.