ELASTICITY
The property of certain materials of returning back to their original position after the removing the
force again.
STRESS
The force of resistance unit area is called "STRESS". It is denoted " σ".
In elastic limit the force of resistance equal to the applied force is called STRESS
the equation of stress σ = P/A
where P- Load or force acting on a body
A- Cross sectional area of body
units - Pa =1N/m2
MPa =1N/mm2
GPa =1KN/mm2
STRAIN
It is defined as deformation of change of length for unit length. It is denoted "ε".
the equation of strain ε=∂l/l
where ∂l= change of length
l = original length
there is no units and its a dimensionless factor
Types of Stresses
1. Tensile Stress
When two forces are applied on the bar or body in opposite direction or opposite pulls.
2. Compressive Stress
When two forces are applied on the bar or body in opposite push or compress the bar or body.
Tensile and Compressive stresses are directive stress.
3. Shear Stress
Two equal and opposite forces are acting tangentially across the resisting section. This figure shows
two plates joint in a rivet.
Types of Strain
1. Tensile Strain
The bar will undergo a changing in length increase under the action of the external force P.
2. Compressive Strain
The bar will undergo a changing in length decrease under the action of the external force P.
Tensile and Compressive strains are directive strain.
3. Shear Strain
The figure shows rectangular block. It's bottom face CD is fixed to the surface an external force
P is applied tangentially along the Top face AB such a force is called Shear force. The CD bottom
face is fixed. There will be distortion of the block. ABCD through angle Ø. The Ø
The property of certain materials of returning back to their original position after the removing the
force again.
STRESS
The force of resistance unit area is called "STRESS". It is denoted " σ".
In elastic limit the force of resistance equal to the applied force is called STRESS
the equation of stress σ = P/A
where P- Load or force acting on a body
A- Cross sectional area of body
units - Pa =1N/m2
MPa =1N/mm2
GPa =1KN/mm2
STRAIN
It is defined as deformation of change of length for unit length. It is denoted "ε".
the equation of strain ε=∂l/l
where ∂l= change of length
l = original length
there is no units and its a dimensionless factor
Types of Stresses
1. Tensile Stress
When two forces are applied on the bar or body in opposite direction or opposite pulls.
2. Compressive Stress
When two forces are applied on the bar or body in opposite push or compress the bar or body.
Tensile and Compressive stresses are directive stress.
3. Shear Stress
Two equal and opposite forces are acting tangentially across the resisting section. This figure shows
two plates joint in a rivet.
Types of Strain
1. Tensile Strain
The bar will undergo a changing in length increase under the action of the external force P.
2. Compressive Strain
The bar will undergo a changing in length decrease under the action of the external force P.
Tensile and Compressive strains are directive strain.
3. Shear Strain
The figure shows rectangular block. It's bottom face CD is fixed to the surface an external force
P is applied tangentially along the Top face AB such a force is called Shear force. The CD bottom
face is fixed. There will be distortion of the block. ABCD through angle Ø. The Ø
