Design of machine elements theories of faliure

Mechanical engineering

1. CAMELLIA INSTITUTE OF TECHNOLGY & MANAGEMENT DEPARTMENT OF MECHANICAL ENGINEERING TOPIC-THEORIES OF FAILURE NAME :ANANTA KUMAR NANDI ROLL NO.:25700722037 REG. NO .:222570120277 OF 2022-23 SUBJECT :(DESIGN OF MACHINE ELEMENTS) {PC-ME602} YEAR :3RD SEM :6TH

2. THEORIES OF FAILURE:-

3. INTRODUCTION:- Failing Factors Principal or Normal Stress Stress Shear Stress Strain Principal Strain Maximum Strain Energy Energy Shear Strain Energy

4. FAILURE CRITERIA’S:- Maximum Principal Stress Maximum Shear Stress Maximum Principal Strain Maximum Strain Energy Density Maximum Distortion Energy Density

5. MAXIMAM PRINCIPAL STRESS THEORY:- 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

6. MAXIMAM SHEAR STRESS THEORY:- When the maximum shear strength in actual case exceeds maximum allowable shear stress in simple tension test the material case. Good for ductile materials

7. MAXIMAM PRINCIPAL STRAIN THEORY:- 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

8. MAXIMAM STRAIN ENERGY DENSITY THEORY:- 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

9. MAXIMAM DISTORTION ENERGY DENSITY THEOTY:- 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. COMPARISION:-

11. FAILURE CRITERION:- Maximum Principal Stress Brittle Material Maximum Principal Strain Maximum Strain Energy Density Maximum Shear Stress Ductile Material Maximum Distortion Energy Density

12. CONCLUSION:- Failure theories help in describing the mechanical components when it starts showing inelastic behaviour . Different modes of stress are put in components. This stress can be very high and could be subjected to failure of functioning of the component.

13. REFERENCES:- Besson J., Steglich D., Brocks W. (2003), Modelling of plain strain ductile rupture, International Journal of Plasticity, 19. Li, Q.M. (2001), Strain energy density failure criterion, International Journal of Solids and Structures 38, pp. 6997–7013. Griffiths, A.A. 1920. The phenomena of rupture and flow in solids. Phil.Trans.Roy.Soc.Lond . A221, 163. sdcadmin (2022-05-05). "What is von Mises Stress?". SDC Verifier. Retrieved 2022-11-03.

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