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MAE 438/538 Smart Materials

MAE 438/538 Smart Materials. Professor Deborah Chung ddlchung@buffalo.edu Furnas Hall, Room 608 Tel. (716) 645-2593 X2243 Fax. (716) 645-3875. Grading scheme for MAE 438. Test 1 25% Test 2 25% Final 50%. Grading scheme for MAE 538. Test 1 20% Test 2 20%

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MAE 438/538 Smart Materials

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  1. MAE 438/538 Smart Materials Professor Deborah Chung ddlchung@buffalo.edu Furnas Hall, Room 608 Tel. (716) 645-2593 X2243 Fax. (716) 645-3875

  2. Grading scheme for MAE 438 • Test 1 25% • Test 2 25% • Final 50%

  3. Grading scheme for MAE 538 • Test 1 20% • Test 2 20% • Final 40% • Paper 20%

  4. Test dates • Test 1: Feb. 3, 2005 • Test 2: Mar. 22, 2005

  5. Smart materials Materials for smart structures

  6. Smart structures Structures that can sense stimuli and respond to them in appropriate fashions

  7. Civil structures • Buildings • Bridges • Piers • Highways • Airport runways • Landfill cover

  8. Lightweight structures • Aircraft • Satellites • Turbine blades • Automobiles • Bicycles • Sporting goods • Wheelchairs • Transportable bridges

  9. Functions for structures • Structural • Vibration reduction • Self-sensing of strain/stress • Self-sensing of damage • Electromagnetic interference (EMI) shielding • Lightning protection • Self-heating (e.g., deicing) • Self-healing

  10. Applications of strain-stress sensing • Traffic monitoring • Weighing (including weighing in motion) • Building facility management • Security • Structural vibration control

  11. Applications of damage sensing • Structural health monitoring • Damage/microstructural evolution study

  12. Damage sensing methods • Acoutic emission • Electrical resistivity measurement • Optical fiber sensor embedment

  13. Piezoresistivity • Change of electrical resistivity due to strain • Gage factor = fractional change in resistance per unit strain (more than 2) • Gage factor up to 700 attained in carbon fiber reinforced cement

  14. Self-healing concept • Embedding microcapsules of monomer in composite • Having catalyst in composite outside the microcapsules • Upon fracture of microcapsule, monomer meets catalyst, thereby former a polymer which fills the crack.

  15. Problems with self-healing • Toxicity of monomer • High cost of catalyst

  16. Types of smartness • Extrinsic smartness • Intrinsic smartness

  17. Advantages of intrinsic smartness • Low cost • High durability • Large functional volume • Absence of mechanical property loss

  18. Advantages of automatic highway • Safety • Mobility

  19. Applications of materials Topic 1

  20. Reading assignment • Chung, “Composite Materials”, Ch. 1 on Applications. • Askeland and Phule, The Science and Engineering of Materials, 4th Edition, Ch. 15 on Polymers.

  21. Applications • Structural applications • Electronic applications • Thermal applications • Electrochemical applications • Environmental applications • Biomedical applications

  22. History of human civilization • Stone Age • Bronze Age • Iron Age • Steel Age • Space Age • Electronic Age

  23. Types of materials • Metals • Ceramics • Polymers • Semiconductors • Composite materials

  24. Ceramics • Ionic/covalent bonding • Very hard (brittle) • High melting temperature • Low electrical/thermal conductivity

  25. Examples of ceramics • Al2O3 (aluminum oxide or alumina) • Fe3O4 (iron oxide or ferrite) • WC (tungsten carbide) • Cement (silicates)

  26. Polymers • Molecules • Soft • Low melting temperature • Low electrical/thermal conductivity

  27. (PVC)

  28. ©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning™ is a trademark used herein under license.

  29. ©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning™ is a trademark used herein under license. Styrene

  30. Examples of polymers • Rubber • Polyester • Nylon • Cellulose • Pitch

  31. Copolymer

  32. Polymer blend

  33. ©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning™ is a trademark used herein under license.

  34. ©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning™ is a trademark used herein under license. Styrene-butadiene block copolymer

  35. Branching

  36. ©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning™ is a trademark used herein under license.

  37. Types of polymer • Thermoplastic (softens upon heating) • Thermoset (does not soften upon heating)

  38. Compression molding

  39. Composites Artificial combinations of materials

  40. Composite materials • Polymer-matrix composites • Cement-matrix composites • Metal-matrix composites • Carbon-matrix composites • Ceramic-matrix composites

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