Functional and smart materials

Transcription

1 Functional and smart materials

2 Engineering from past to present One of the scopes of the engineers has always been the realization of components to optimally respond to the requested needs. The materials where just chosen to build the component in a way it can resist to all the loads, conditions, temperatures, vibrations etc. So the process was focusing more on assembling all materials and pieces to reach the goal, the device. Now there is a different perspective: we can think about a material able to directly perform some actions (active role) and not only a passive role.

3 The robot in the fiction: yesterday and today Robbie the robot: mechanic & electronic Terminator II: smart rheological materials

4 What is a smart material? Material responding functional smart? Something is changing?

5 Smart building DUOX system to reduce seismic vibrations and wind effect HMD system: Hybrid Mass Damper With SMA it is possible to realize a simpler system

6 Electronic paper? Already done at MIT! A newspaper that change content every day?

7 Micro/nano movements/actuators Traditional way using silicon components (MEMS) Functional materials? SMA beam Micropump in Nitinol But we need a motor!

8 Piezoelectric and electrostriction ceramics Sensors for vibrations, inclination, pressure, sonar, infrared, etc. Very precise actuators: aerospace applications, acoustic, micropositioning, etc.

9 Photochromic, photoluminescence glasses

10 Leghe Shape a memoria Memory Alloys di forma (SMA) (SMA)

11 Magneto and electro-rheological fluids/materials ER fluid MR fluid

12 Hydrogels Microvalves activated by ph Drug delivery systems

13 Porous membrane: ion gates

14 Shape memory polymers Smart suture wires

15 Thermoelectrics Thermoelectric generator Peltier cooling

16 Magnetocaloric materials

17 Applicazioni Morphing applications morphing

18 From functional to smart materials The functional material is able to perform an action to respond to a stimulus (temperature, electric field changes, etc.). As for thermal expansion all materials should be considered functional then. A functional material is able to substitute an entire more complex device composed by several parts (more simple and compact). The smart material is able to respond to different stimuli and to adapt its response to the need. In reality is more appropriate to talk about functional materials and smart structures (composed by functional materials).

19 Nature creates several smart materials The material is self adapting (true smart material)

20 Class content Materials: Type I (property change as a response of an external stimulus) Shape memory (alloys, ceramics, polymers, hydrogels) Magneto(electro)rheological Thermochromic Thermotropic (liquid crystals) Photomechanical Type II (energy conversion) Piezoelectric (pyroelectric, electro-optic) Electro(magneto)striction Thermoelectric Photoluminescent Photovoltaic Type III (phase change materials): Optical storage materials Magnetocaloric Others: Self-healing materials

21 Class content (applications) Applications (mechatronic): Mechanical, optical, electronic devices Actuators, positioning systems Sensors Applications (biomedical): dental wires, stents, micropumps, clamps and release systems suture wires, guides drug delivery systems Applications (energy): transformer sensors actuators Applications (generals): MEMS valves and controls antitheft systems, optical and dynamical protections

22 Additional infos Teachers: Luca Lutterotti office DII (Povo2), phone: availability: friday 9:30-10:30, thursday 14:30-15:30 or by appointment ( ) Stefano Gialanella, , (shape memory alloys)

23 Additional infos Exam: only oral 3 questions on different arguments (it is possible to avoid one question by presenting a report made by the student on one argument on smart and functional materials - not necessarily done in class) Resources: A. J. Moulson & J. M. Herbert, Electroceramics: Materials, Properties, Applications, Chapman and Hall (1 st ed.) / John Wiley & Sons Canada (2003) (2 nd ed.) Encyclopedia of Smart Materials M. Addington & D. Schodek, Smart Materials and Technologies, Elsevier, 2005 (as lecture)

24 Time schedule Mechatronic Materials

25 Lutterotti Shape Memory Materials Piezoelectrics Pyroelectrics Electro-optic Chalcogenide/ Fiber optics Electro/ Magnetostriction ER/MR Thermoelectrics/ Magnetocaloric Gialanella (Shape memory alloys)