2. Strain Linear strain-displacement relationships What is the physical meaning of the strain components? What is the maximum normal and shear strains that aluminum can take before yielding? Are these tensorial or engineering shearing strains? What is the difference between them?

3. Stress Components of the stress tensor What is the convention with the subscripts of the stress components? What is a tensor? Give examples of other tensors?

4. Stress-strain relationships Hooke’s law (Robert Hooke, 1635-1703) an English natural philosopher, architect and polymath. For most general material Symmetry from energy considerations (21 coefficients)

5. Isotropic case

6. Isotropic coefficients

7. Equilibrium equations Without body forces In a cantilever beam under an end load, the normal stress is proportional to the distance from the neutral axis and to the distance from the support. What does it tell you about the shear stress? We have six stress components and only three equations. How can we solve them?

8. Plane stress

9. It is not plane strain!