1. A great teacher never strives to explain his vision. He simply invites you to stand beside him and see for yourself. – R. Inman A great teacher never strives to explain his vision. He simply invites you to stand beside him and see for yourself. – R. Inman

2. Composites Fibers - variables amount fiber length distribution orientation Fibers - variables amount fiber length distribution orientation

3. Composites

4. Fibers - variables amount fiber length distribution orientation Fibers - variables amount fiber length distribution orientation Fiber orientation can be random aligned intermediate Fiber orientation can be random aligned intermediate

5. Composites

6. Materials selection - some considerations Economics Environmental Political Market Aesthetics Material properties Economics Environmental Political Market Aesthetics Material properties

7. Materials selection - material cost Relative cost - compared to that of hot rolled ASTM A36 plate (0.29C-1Mn- 0.28Si) (unit wt. basis) Relative cost - compared to that of hot rolled ASTM A36 plate (0.29C-1Mn- 0.28Si) (unit wt. basis)

8. Materials selection - environmental Health hazards Recycling Health hazards Recycling Metals particularly suited to recycling - can be easily sorted, remelted, & shaped Ceramics usually not recycled - many polymers are Composites difficult to recycle - difficult to separate fibers from matrix when drawing SS to rod need lubricant

9. Materials selection - political Who writes the specs for contract bids? Will they specify stainless steel rebar in roads & bridges? Who writes the specs for contract bids? Will they specify stainless steel rebar in roads & bridges?

10. Materials selection - market Carrera GT vs …… Kia vs ……

11. Materials selection - aesthetics

12. Materials selection - properties

15. P=50 500 MPa

16. Materials selection - properties 500 MPa

17. Assignment: Review today's classnotes a. fiber characteristics & behavior b. selection considerations c. use of Ashby charts Read pp. 144-151 Assignment: Review today's classnotes a. fiber characteristics & behavior b. selection considerations c. use of Ashby charts Read pp. 144-151

18. Composites - polymer matrix composites (PMCs) Role of matrix in FR composites: a. transfer stresses betwn fibers b. provide barrier to environment c. protect fibers Role of matrix in FR composites: a. transfer stresses betwn fibers b. provide barrier to environment c. protect fibers Slow crack growth deflect crack tips redistribute stresses around crack tips bridge crack tips Slow crack growth deflect crack tips redistribute stresses around crack tips bridge crack tips A great many people think they are thinking when they are merely rearranging their prejudices. (William James)William James