PPT: Stress & Strain

# PPT: Stress & Strain | Strength of Materials (SOM) - Mechanical Engineering PDF Download

``` Page 1

TOPICS
• Topic cover
– Stress and strain
• Introduction to stress and strain, stress strain diagram
• Elasticity and plasticity and Hooke’s law
• Shear Stress and Shear strain
• Axial force and deflection of body
– Torsion
• Introduction, round bar torsion, non-uniform torsion.
• Relation between Young’s Modulus E, ? and G
• Power transmission on round bar
Visit for more Learning Resources
Page 2

TOPICS
• Topic cover
– Stress and strain
• Introduction to stress and strain, stress strain diagram
• Elasticity and plasticity and Hooke’s law
• Shear Stress and Shear strain
• Axial force and deflection of body
– Torsion
• Introduction, round bar torsion, non-uniform torsion.
• Relation between Young’s Modulus E, ? and G
• Power transmission on round bar
Visit for more Learning Resources
Stress and strain
DIRECT STRESS
? When a force is applied to an elastic body, the body deforms. The way in
which the body deforms depends upon the type of force applied to it.
Compression force makes the body shorter.
A tensile force makes the body longer
?
Page 3

TOPICS
• Topic cover
– Stress and strain
• Introduction to stress and strain, stress strain diagram
• Elasticity and plasticity and Hooke’s law
• Shear Stress and Shear strain
• Axial force and deflection of body
– Torsion
• Introduction, round bar torsion, non-uniform torsion.
• Relation between Young’s Modulus E, ? and G
• Power transmission on round bar
Visit for more Learning Resources
Stress and strain
DIRECT STRESS
? When a force is applied to an elastic body, the body deforms. The way in
which the body deforms depends upon the type of force applied to it.
Compression force makes the body shorter.
A tensile force makes the body longer
?
A
F
Area
Force
Stress ? ? ? ?
2
/m N
Tensile and compressive forces are called DIRECT FORCES
Stress is the force per unit area upon which it acts.
….. Unit is Pascal (Pa) or
Note: Most of engineering fields used kPa, MPa, GPa.
( Simbol – Sigma)
Page 4

TOPICS
• Topic cover
– Stress and strain
• Introduction to stress and strain, stress strain diagram
• Elasticity and plasticity and Hooke’s law
• Shear Stress and Shear strain
• Axial force and deflection of body
– Torsion
• Introduction, round bar torsion, non-uniform torsion.
• Relation between Young’s Modulus E, ? and G
• Power transmission on round bar
Visit for more Learning Resources
Stress and strain
DIRECT STRESS
? When a force is applied to an elastic body, the body deforms. The way in
which the body deforms depends upon the type of force applied to it.
Compression force makes the body shorter.
A tensile force makes the body longer
?
A
F
Area
Force
Stress ? ? ? ?
2
/m N
Tensile and compressive forces are called DIRECT FORCES
Stress is the force per unit area upon which it acts.
….. Unit is Pascal (Pa) or
Note: Most of engineering fields used kPa, MPa, GPa.
( Simbol – Sigma)
?
L
x
Strain ? ? ?
?
DIRECT STRAIN ,
In each case, a force F produces a deformation x. In engineering, we
usually change this force into stress and the deformation into strain
and we define these as follows:
Strain is the deformation per unit of the original length.
The
symbol
Strain has no unit’s since it is a ratio of length to length. Most
engineering materials do not stretch very mush before they become
damages, so strain values are very small figures. It is quite normal to
change small numbers in to the exponent for 10
-6
( micro strain).
called EPSILON
Page 5

TOPICS
• Topic cover
– Stress and strain
• Introduction to stress and strain, stress strain diagram
• Elasticity and plasticity and Hooke’s law
• Shear Stress and Shear strain
• Axial force and deflection of body
– Torsion
• Introduction, round bar torsion, non-uniform torsion.
• Relation between Young’s Modulus E, ? and G
• Power transmission on round bar
Visit for more Learning Resources
Stress and strain
DIRECT STRESS
? When a force is applied to an elastic body, the body deforms. The way in
which the body deforms depends upon the type of force applied to it.
Compression force makes the body shorter.
A tensile force makes the body longer
?
A
F
Area
Force
Stress ? ? ? ?
2
/m N
Tensile and compressive forces are called DIRECT FORCES
Stress is the force per unit area upon which it acts.
….. Unit is Pascal (Pa) or
Note: Most of engineering fields used kPa, MPa, GPa.
( Simbol – Sigma)
?
L
x
Strain ? ? ?
?
DIRECT STRAIN ,
In each case, a force F produces a deformation x. In engineering, we
usually change this force into stress and the deformation into strain
and we define these as follows:
Strain is the deformation per unit of the original length.
The
symbol
Strain has no unit’s since it is a ratio of length to length. Most
engineering materials do not stretch very mush before they become
damages, so strain values are very small figures. It is quite normal to
change small numbers in to the exponent for 10
-6
( micro strain).
called EPSILON
MODULUS OF ELASTICITY (E)
•Elastic materials always spring back into shape when released.
They also obey HOOKE’s LAW.
•This is the law of spring which states that deformation is directly
proportional to the force. F/x = stiffness = kN/m
•The stiffness is different for the different material and different sizes of the
material. We may eliminate the size by using stress and strain instead of
force and deformation:
•If F and x is refer to the direct stress and strain , then
A F ? ?
L x ? ?
L
A
x
F
?
?
?
?
?
?
Ax
FL
hence and
```

## Strength of Materials (SOM)

37 videos|39 docs|45 tests

## FAQs on PPT: Stress & Strain - Strength of Materials (SOM) - Mechanical Engineering

 1. What is stress and strain in materials?
Ans. Stress is the force applied to a material per unit area, while strain is the resulting deformation or change in shape of the material. Stress and strain are measures of how a material responds to external forces or loads.
 2. How are stress and strain related?
Ans. Stress and strain are related through the material's elastic modulus, also known as Young's modulus. Young's modulus is a measure of the material's stiffness and describes the ratio of stress to strain. It determines how much a material will deform under a given amount of stress.
 3. What are the different types of stress?
Ans. There are three main types of stress: tensile stress, compressive stress, and shear stress. Tensile stress occurs when a material is stretched or pulled apart, compressive stress occurs when a material is compressed or pushed together, and shear stress occurs when a material is subjected to forces parallel to its surface.
 4. How does stress affect the behavior of materials?
Ans. Stress can cause materials to deform, break, or undergo permanent changes in shape. The behavior of materials under stress depends on their properties, such as elasticity, plasticity, and strength. Some materials may exhibit elastic deformation, where they return to their original shape once the stress is removed, while others may undergo plastic deformation, where the shape change is permanent.
 5. What factors can influence the stress and strain of a material?
Ans. Several factors can influence the stress and strain of a material, including the material's composition, temperature, loading rate, and external environment. Different materials have different strengths and stiffnesses, and they may respond differently to stress and strain depending on these factors. Additionally, temperature can affect the behavior of materials by altering their thermal expansion coefficients and causing changes in their mechanical properties.

## Strength of Materials (SOM)

37 videos|39 docs|45 tests

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