1. Properties of Metals

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1. What is stress?
The internal resistance offered by a body per unit area against
deformation is known as stress. The unit of stress is N/mm2 or
N/m2 When an external force acts on a body, the body tends to
undergo deformation. Due to cohesion between molecules the
body resist the force. This resistance offered by the body is known
as strength of material

2. What is tensile stress?
Tensile stress: The resistance offered by a body per unit area
when it is subjected to a force which acts away from its point of
application is called tensile stress.

3. What is compressive stress?
Compressive stress: The resistance offered by a body per unit
area when it is subjected to a force which acts towards its point of
application is called compressive stress.

4. What is shear stress?
Shear Stress:The resistance offered by a body per unit area
when the applied load on the body consists of two equal and
opposite forces not in the same line is called shear stress.

5. What is strain?
when a body is subjected to some external force, there is
some deformation of the body. The ratio of change of dimension of
the body to the original dimension is known as strain. It has no
unit.

6. What is Tensile strain?
The length of the bar increases by an amount under the action of
external force P then

7. What is compressive strain?
The length of the bar decreases by an amount under the action of
external force P then                                                                Compressive Strain =

8. What is Shear strain?
The distortion produced by shear stress on an element or
rectangular block is known as shear strain. It can also be defined
as the change in the right angle.

9. What is volumetric strain?
The ratio between the change in volume and the original volume
is known as volumetric stain.

10. Define True stress and True Strain
The true stress is defined as the ratio of the load to the cross
section area at any instant.

11. Define Hooke’s law?
Within the elastic limit, when a body is loaded, then stress
induced is proportional to the strain. This is called as Hook’s law.

12. What is linear strain?
The ratio of increase or decrease in length to the original
length is called as linear strain.

13. What is lateral strain?
The ratio of increase or decrease in lateral dimensions to
the original lateral dimensions is called as lateral strain.

14.What are the types of elastic constants?
 1)Modulus of elasticity or Young’s modulus
 2)Modulus of rigidity or shear modulus
 3)Bulk modulus

15. What is poison’s ratio?
When a member is stressed with in elastic limit, the ratio of
lateral strain to its corresponding linear strain remains constant
is the ratio of lateral strain to longitudinal or linear strain.

16. What is the inter relationship between the three constants? Where, E = Young’s modulus in N/mm2
K = Bulk modulus in N/mm2
G = Modulus of rigidity in N/mm2 μ Poisson’s ratio

17. Define bulk modulus?
When a body is stressed the ratio of direct stress to the
corresponding volumetric strain is constant with in elastic limit.
This constant is called as bulk modulus. Bulk modulus is the ratio
of direct stress to volumetric strain.

18. Define modulus of elasticity?
Modulus of elasticity is the ratio of stress to strain.

19. Define factor of safety?
Factor of safety is defined as the ratio of ultimate stress to
the working stress (permissible stress).

20. What is elasticity?
The deformation produced due to the application of
This property of the material is called as elasticity.

21. What is elastic limit?
Elastic limit is the limiting value of the load up to which the
material returns back to its original position. Beyond this load, the
material will not return back to its original position.

22. What are thermal stresses and strain?
Whenever there is increase or decrease in the temperature of the
body, the body tends to expand or contract. If this deformation is
prevented, some stresses are induced in the body, these stresses
are called as thermal stresses or temperature stresses. The
corresponding strains are thermal strain or temperature strains.
Thermal stress is σt =α T E where α is co-efficient of linear
expansion, T is rise in temperature E is young’s modulus

23. If the values of E and μ for an alloy body is 150 GPa and 0.25
respectively, find out the value of bulk modulus for the alloy?

24. Differentiate between Ultimate stress and working stress?
Ultimate stress is the maximum value of stress up to which
the material withstand its failure. Working stress is the maximum
stress allowed to setup in a material in actual practice.

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