1. Failure of laminated composites Progressive failure is needed to predict ultimate failure We will limit ourselves to first ply failure

2. Maximum strain or maximum stress failure – in plane loads

3. Example 6.3.1 Prequel

4. Tsai-Pagano constants

5. A* matrix and laminate strains

6. 45-deg ply

7. Other load combinations

8. Laminate failure envelope Combining the two envelopes Does it agree with previous calculations?

9. If we wanted to check using Hoffman First need to translate strain limits to stress limits (in Gpa) Next calculate stresses in 0-deg ply How does it look? Please check.

10. Terms in Hoffman Criterion Ratios: Criterion adds up to 6.1, large violation. By how much approximately do we need to reduce the stresses? Why the large discerpancy between the two criteria?