and Actuation Cover Photo Courtesy: Dr. Manuel Ochoa, Purdue University:

Transcription

1 Smart Materials for Sensing and Actuation Bishakh Bhattacharya Department of Mechanical Engineering Indian Institute of Technology Kanpur Cover Photo Courtesy: Dr. Manuel Ochoa, Purdue University:

2 Organization Application of Smart Material Smart systems using Smart Materials Smart Actuators Direct and Reverse Effects Shape Memory Effect Self Healing

3 Five Major Applications Vibration and Chatter Control Shape Control Micro-Positioning Devices Distributed Sensing Energy Harvesting for Wireless Sensor Networks

4 Active Vibration Control The liquid contained in the dampers has magneto-rheological properties. Tiny magnetic particles are bound inside the basic oil which is used to fill the dampers. When a magnetic field is applied, the magnetic particles are aligned against the direction of movement of the damper. This allows the firmness of the dampers to be increased or decreased within a fraction of a second.

5 Active Shape Control Laser-Micromachined Magnetically- Functionalized Hygroscopic Bilayer: A Low-Cost Smart Material

6 Micro-Positioning Devices A P-545 PInano XY & XYZ Piezo Stages for Microscope Slides Sub-nanometer resolution 200 µm Travel Ranges Extremely Fast Step & Settle, From 5 msec

7 Energy Harvesting Sensors A typical thermoelectric (TE) energy harvesting system of five key components TE generator, heatsink, voltage regulation, charge management and energy storage, and power/load management

8 Input Output Current/Charge Magnetization Strain Temperature Light Electric Conductivity Electromagnetic Reverse Ohmic Electro-Optic Field Permittivity Effect Piezoelectric Resistance effect Effect SA Magnetic Eddy Current Effect Joule Effect Magneto-caloric Magneto-Optic Field Permeability Magnetostriction Effect effect SA Stress Direct Piezoelectric Villary Effect Thermo- Photo-elastic Effect Elastic Modulus Mechanical Effect SS SS Effect SS SS Heat Pyroelectric Effect Thermo- Thermal Thermo- magnetization Expansion/Phase Specific Heat luminescence Transition SA Light Photo-voltaic Effect Photo- Photostriction Photo-thermal Refractive magnetization SA effect Index

9 Smart Actuators Input Parameter Actuator Type/ Devices Electric Field Piezoelectric/ Electrostrictive Electrostatic (MEMS) Electro- Rheological Fluid Magnetic Field Magnetostrictive Magneto-Rheological Fluid Chemical Heat Mechano-chemical Shape Memory Alloy Shape Memory Polymer Light Photostrictive

10 Properties important for Actuation Maximum free strain (Λ) in microns Young s Modulus (GPa) Piezoelectric Material Magnetostrictive Material Phase-transition dependent Material Piezoceramic PVDF Terfenol-D Nitinol FSMA ,000 30, M phase, 90 A- phase Bandwidth 0.1 Hz- GHz 0.1 Hz-GHz 0.1 Hz-10KHz 0-10 Hz 100 Hz

11 Traditional VS New Actuators Drive Device Displacement Accuracy Torque/Generative Force Response Time Air Pressure Motor Rotation degrees 50 Nm 10 sec Cylinder 100mm 100µm 10-1 N/mm 2 10 sec Oil Pressure Motor Rotation degrees 1000 Nm 1 sec Cylinder 1000mm 10µm 100 N/mm 2 1 sec Electricity AC Servo Rotation minutes 30 Nm 100 msec DC Servo Rotation minutes 200 Nm 10 msec Linear Stepper 1000mm 10µm 300 N 100 msec Voice-Coil 1mm 0.1µm 300 N 1 msec Piezoelectric 100µm 0.01µm 30 N/mm msec Magnetostrictive 100µm 0.01µm 100 N/mm msec Ultrasonic Motor Rotation minutes 1 Nm 1 msec

12 Smart Materials as Sensors & Actuators Input Stress Output Signal Direct Effect Output Electric Potential Input Stimulus Output Strain Reverse Effect Input: Electric/Magnetic / Thermal

13 Inspirations from Animal Locomotion Motor based Rigid Robots Snake Like ACM R5 Quadruped Stairclimber Titan - 6 Bi-pedal Walking Robot M2

14 Muscle based Flexible Robots Pneumatic Artificial Muscle (PAM)

15 Smart Muscles based on Shape Memory Alloys and Electroactive Polymer

16 What is Shape Memory Effect? There are two common shape memory effects - One Way and Two Way effects. In the case of One Way effect, the material always remembers the shape at Parent State (Austenite Phase) In the case of Two Way effect, the material is trained to remember two shapes, one at the Parent Austenite phase and the other at the Martensite Phase

17 Hysteresis Curve of SMA M s : Martensite start temperature, M f : Martensite finish temperature, A s : Austenite start temperature and A f : Austenite finish temperature

18 Crystal Structure Depicting SME

19 One-Way SME

20 Pseudo-elasticity

21 Stress-induced Transformation

22 Metallic Alloys that show SME SME was first observed in 1932 in Silver Cadmium Alloy Three types of SMA are currently popular Cu Zn Al Cu Al Ni and Ni Ti The last one is commercially available as NiTiNOL (NOL Naval Ordinance Laboratory)

23 Space Application of SMA: Control of aerodynamic surfaces Micro-coils for vibration isolation Grasping by robotic fingers Space exploration: rock splitting by ESA Nitinol filter Deployment of Solar Array Hinges (EMC)

24

25 Advantage of Module-Locking

26

27

28

29

30 An SMA based Trajectory Tracking System

31 An SMA based Sensor

32 Another SMA based Sensing Shape Memory Alloy (SMA) based Sensor for Two-Phase Flows

33 Experiment Results

34 A Mix of Sensing and Actuation

35 Experimental Setup: SMA spring for unlocking Metallic strip Bearing SMA spring inserts Auto locking mechanism Flexible Antenna System SMSS Laboratory, IIT Kanpur 35

36 Self-Healing

37 Google Solara 50 Crash due to Large Wing Deformation Google's solar-powered plane, designed to deliver free internet from the skies, crashed in New Mexico shortly after takeoff. Source: National Transportation Safety Board Report 2017 The unmanned Solara 50 experienced a sudden change in speed that caused its wing structure to deform, and partially collapse leading to a drastic turn which the operator wasn't able to control.

38 INTRODUCTION Corrosion Pit triggered Crash of Aircraft The M18 Dromader was carrying out water bombing operations for the Rural Fire Service when it crashed near Ulladulla in October The final report from the Australian Transport Safety Bureau (ATSB) found the wing separated from the plane due to a fatigue crack in the lower attachment fitting, which was originated from small corrosion pits. Source: ABC News by Nick McLaren Posted 16 Feb 2016, 3:51am The corrosion pits were not successfully removed during maintenance, and the unapproved inspection method may not have been effective in detecting the crack.

39 . What is Self-Healing? The ability of a material to carry out autonomous healing against damages such as cracks, ruptures or punctures by drawing a healing material either from inside or from an outside source. All living materials in nature demonstrate this property. Consider the bone Ramchandran Plot of Collagen Structure

40 Self Healing in Plants Some Plants are able to heal due to high-level of dedifferentiation, a process whereby mature cells withdraw from their specialized role and acquire proliferation ability and Pluripotency, enabling them to develop anew into different cell types like the Hypocotyls. 6/30 ISSS 2017 June 17, 2017

41 Strategies for Self Healing: Encapsulated Healing Material Passive Technique: DCPD based Autonomic Self Healing proposed by White et al (2000) Healing is accomplished by incorporating a microencapsulated healing agent and a catalytic chemical trigger within an epoxy matrix. An approaching crack ruptures embedded microcapsules, releasing healing agent into the crack plane through capillary action. Polymerization of the healing agent is triggered by contact with the embedded catalyst, bonding the crack faces. The damage-induced triggering mechanism provides site-specific autonomic control of repair. The reaction polymerizes dicyclopentadiene (DCPD) at room temperature in several minutes to yield a tough and highly cross-linked polymer network. DCPD-filled microcapsules ( µm) with a urea-formaldehyde shell were prepared using standard microencapsulation techniques.

42 Strategies for Self Healing by using Activated Hydrogels Due to the nature of Supramolecular polymers, the non-covalent interactions make supramolecular polymers more dynamic and reversible. Such properties enable supramolecular polymers to construct a dynamic and reversible network, which are able to develop self-healing materials based on noncovalent bonds. Compared with self-healing materials based on covalent bonds, these supramolecular polymer-based self-healing materials can restore the initial structure and function of polymers before being exposed to damages, and can also undergo repeating damage-heal process % G' G'' G'/G'' %strain Arindam et al (2014)

43 Strategies for Self Healing Passive Technique: Vascular Self- Healing Requires special PTFE 3D Microchannels for spreading the Healing Agent with Acetonitrile. In case of rapture, the low viscosity MDI flows out. Presence of moisture is essential as the Viscosity of MDI increases in reaction with water. Damage initiates Polyurea formation. Once enough Polyurea formation takes place, the moisture level comes down and the MDI-Acetonitrile solution continues to flow in the vascular system.

44 Issues with Intrinsic Self Healing 1. Generally, healing is initiated passively and does not detect the damage at an early stage and initiate healing. 2. Self-healing is typically an open loop process with no regulation of the healing process to counteract the onset of damage. As a result, the process might be unable to achieve the desired healing response and handling of uncertainty/disturbance is also likely to be poor. 3. There is usually no controllable mechanism to terminate the process. For example, healing agent stops bleeding into the damaged zone when flow is restricted.

45 Extrinsic Self-healing Regulating the healing rate involves controlling factors that can affect the reaction kinetics of a healing process. Factors such as the speed of delivery/mass flow rate, release mechanism, temperature, catalyst, pressure, concentration and ph level may vary from system to system. Sensor Type Damage type Self-Healing Material Pressure Delamination Vascular GFRP Fibre Optics Delamination Vascular CFRP Photo Resistor Acoustics Emission Cracks Intrinsic TP Cracks Vascular Epoxy

46 In search of a Solid Self-healing Agent Similar to Bone: A Mechanism is proposed based on Redistribution of Structural Mass in response to Stress Gradients in a Dynamic Environment. Electrochemical Redistribution triggered by Voltage Generation due to change in stress-field Poly vinylidene fluoride-cohexafluropropylene (PVDF-HFP), zinc oxide and copper nanoparticles are mixed together to form a PVDF-HFP solid electrolyte. Carbon fibre reinforcement and the PVDF-HFP solid electrolyte are combined to form composite laminates and held together by bolts which also act as electrodes.

47 Extrinsic Self-healing Because of the high density of fluorine groups, PVDF-HFP has a high coordinating ability with many metal ions; this leads to relatively high levels of ionic conductivity. Fluorine can further form H-bonds, which provide the system with pseudo cross-linking and thus enhance mechanical attributes.

48 Extrinsic Self-healing Concept using Smart Sensor

49 Future Scope of Advancement Improvement of Passivation Strength vs Reversibility Integrate the system in a composite structure Integrate with Predictive Prognosis Capability Supply of Healing Material Identification of Critical Healing Regions

50 Future of Smart Polymers Higher IQ responsiveness larger actuation corresponding to smaller stimulation, agility faster response increasing the bandwidth of the existing smart materials Higher order functionality - self-sensing, selfactuation, self-healing, auto-phagous, energy harvesting, energy scavenging Exploit the success in nano -technology and develop more varied, complex and intelligent systems

51 THANK YOU