1 SHAPE MEMORY ALLOY I.i.t. Indore R.r.c.a.t. indore Under the guidance of:DR. I.A. PalaniDr. C.p. PaulPresented by:Sandesh DhurveNishchay Sharma
2 contents Research Objective Project Title Overview Introduction to Shape Memory AlloyNitinolRapid Manufacturing using LasersExperimental setupObtained resultsSpring & Parallel ManipulatorCAD modelAnalysis using ANSYSReferences
3 Research Objective Rapid Manufacturing of Nitinol using Lasers Deposition of Ni-Ti powder on Ti plate using High power Laser depositionManufacturing of a leaf springParallel Manipulator with SMA springsCAD modeling of the parallel manipulatorModeling of helical and leaf springsAnalysis using ANSYSAnalyzing the behavior of SMA springs with respect to temperatureStudy of the actuation mechanism of SMA springs in 3-DOF parallel manipulator
4 Shape Memory Alloy It remembers its shape Deformed shape + Heat = Original shapeThe high temperature causes the atoms to arrange themselves into the most compact and regular pattern possibleExample: Copper-Aluminum-Nickel,Copper-Zinc-Aluminum,Iron- Manganese-Silicon andNickel-Titanium alloys
5 APPLICATIONS SMA have applications in industries like- Medical: Mending bones, Stent in artries, Eyeglass frames, Tooth clipsMilitary: Nitinol couplers in F-14 fighter planesSafety: Anti-scalding devices and fire sprinklersRobotics: As an actuator
6 NITINOL (Ni-Ti)Temperature (K)Young's Modulus (GPa)294.2527.17299.8524.82305.3522.41310.9520.06316.4525.72322.0531.37327.5536.96333.1542.61338.7548.27344.2554.88349.8561.43355.3564.19360.9563.16366.4562.06372.0563.92377.5565.78383.1567.64388.7569.5394.2571.36399.8570.81405.3570.33410.9569.78416.4569.29Was discovered in Naval Ordnance Laboratory (NOL), Maryland, USANi- 50% , Ti- 50%FACT: Even 0.l wt% variation of composition causes 10 K error of transformation temperature.HIGHLY SENSETIVE TO COMPOSITION!!
7 SME in NiTinol By change in phase from Martensite to Austenite Monoclinic FCC (Martensite) to BCC (Austenite)
8 ADVANTAGESCompactness, allowing for reduction in overall actuator size.Very high power/weight ratio comparativelyAccessible voltages can accomplish thermo elastic transformationHigher strain recoveryHigher strengthNoiseless and silent operationHigh corrosion resistance
9 LIMITATIONS Heat Dissipation, need Mechanism for cooling Less Stiffness / high FlexibilityRelatively expensive to manufacture and machine compared to other materials such as steel and aluminum.Most SMA's have poor fatigue properties ( a steel component may survive for more than one hundred time more cycles than an SMA element. )
10 Rapid manufacturing using lasers (LRM) STEP TOWARDS FEATURE BASED DESIGN & MANUFACTURINGEXTENSION OF LASER CLADDING PROCESSDeposition of a metal on anotherMetallurgical bonds are formedFABRICATION OF PARTSCAD ModelPowder Material
11 Experimental setup CNC Ti Ni Schematic diagram: Powder Feeder Ni + Ti powderNiTiPowder FeederCNCHigh power Laser5 axes manipulator with CNC controlArgon atmosphere (965 mbar)No moisture!!Closed loop process controlDue to diffusion processes in the system, the melting point decreases. Moreover, formation of intermetalic phases, which is usually exothermic, increases temperature of the system. It causes occurrence of eutectic an peritectic systems and melting the batch, which improves homogenization of the system.Guide LaserMarking the trajectoryƛ=605nmRed color laserNozzleLaser nozzle dia.= 3.29mmPowder feed nozzle dia.=1.96mmDepositionMelting of powder by power laser (IR) ƛ=1080nmPower of laser= 700WDeposition mechanism of Ni-Ti powder on Ti plate
12 POWER LASER SPECIFICATIONS ƛ=1080nm (IR laser); feed= 4gm/minYtterbium laser system YLS-2000A coolant is used for cooling the nozzle.Temperature of nozzle is kept around CMaximum power of the laser= 2000WPower during process= 700WPower of the laser is adjusted to get proper penetration, melting and deposition. Less power causes poor melting and high power causes sputtering!!LRM based CNC Machine
13 Modeling & Simulation Helical spring Diameter of spring…………………..D = 1.5mmWire diameter………………………..d = 0.5 mmNumber of turns……………………..n = 40Length of fully compressed spring….L= 20 mmLeaf springRectangular cross section…………..w = 5mmh = 5mmArc radius…………………………..r = 37.5 mmParallel manipulator with helical springParallel manipulator with leaf spring
22 REFERENCES http://www.stanford.edu/~richlin1/sma/sma.html Peter R. Barrett, Daniel Fridline. “User Implemented Nitinol Material Model in ANSYS”.Kaan Divringi & Can Ozcan. “Advanced Shape memory alloy material models for ANSYS”. Ozen Engineering Inc.Eiji makino, Takashi Mitsuya, Takayuki Shibata. “ Fabrication of TiNi shape memory actuator for micropump”. Proc. SPIE 3891, Electronics and Structures for MEMS, 328 (September 29, 1999); doi: /Shape Memory Alloy, BTP Report by Saurabh Maghade and Sahil Agarwal.