2. Introduction
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Failing Factors
Principal or Normal Stress
Stress
Shear Stress
Strain Principal Strain
Maximum Strain Energy
Energy
Shear Strain Energy
3. Failure Criteria's
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• Maximum Principal Stress
• Maximum Shear Stress
• Maximum Principal Strain
• Maximum Strain Energy
Density
• Maximum Distortion
Energy Density
4. Maximum Principal Stress Theory
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When the maximum
principal stress induced in a
material under complex load
condition exceeds the
maximum normal strength
in a simple tension test the
material fails
Good for brittle
materials
5. Maximum Shear Stress Theory
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When the maximum
shear strength in actual case
exceeds maximum allowable
shear stress in simple
tension test the material
case.
Good for ductile
materials
6. Maximum Principal Strain Theory
Saturday, August 29, 2015 Kumar Katturaja | CAE Engineer 6
When the maximum
normal strain in actual case
is more than maximum
normal strain occurred in
simple tension test case the
material fails
Not recommended
7. Maximum Strain Energy
Density Theory
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When the total strain
energy in actual case
exceeds the total strain
energy in simple tension
test at the time of failure,
the material fails
Good for ductile
material
8. Maximum Distortion Energy
Density Theory
Saturday, August 29, 2015 Kumar Katturaja | CAE Engineer 8
When the shear strain
energy in the actual case
exceeds shear strain energy
in simple tension test at the
time of failure the material
fails
Highly recommended
10. Failure Criterion
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Maximum Principal Stress
Brittle Material Maximum Principal Strain
Maximum Strain Energy
Density
Maximum Shear Stress
Ductile Material
Maximum Distortion
Energy Density
