MEC E380 Lecture Notes - Lecture 4: Material Failure Theory, Rela, Shear Modulus

• School: University of Alberta
• Department: Mechanical Engineering
• Course: MEC E380
• Professor: Cagri Ayranci

Document Summary

Sections 3. 12, 4. 1 to 4. 12, 4. 17 in textbook. 4. 2. 1 biaxial stress state and mohr"s circle 4-4. 4. 3. 2 guidelines to selecting safety factor 4-8. 4. 4. 3. 1 brittle material: maximum normal stress criterion 4-19. 4. 4. 3. 2 modified ii mohr failure theory 4-21. 4. 4. 4. 2 von mises distortion energy criterion 4-26. This section is the wrap up of unit 1: failure of structures from applied loads. In the previous sections we looked at characteristic of homogeneous, isotropic linear elastic materials such as strength, elastic and shear modulus and poisson"s ratio. We also looked at local stresses and strains and the relationship between them in terms of materials elastic constants. We also defined von mises stress based on principles of strain energy. Having all this information, we can now determine if a structure will fail. To accomplish this we must be able to calculate the safety factor of a system using the appropriate failure criterion and by considering geometrical effects of local stresses.