SHAPE MEMORY ALLOY I.i.t. Indore R.r.c.a.t. indore Under the guidance of: DR. I.A. Palani Dr. C.p. Paul Presented by: Sandesh Dhurve Nishchay Sharma

contents Research Objective Project Title Overview Introduction to Shape Memory Alloy Nitinol Rapid Manufacturing using Lasers Experimental setup Obtained results Spring & Parallel Manipulator CAD model Analysis using ANSYS References

Research Objective Rapid Manufacturing of Nitinol using Lasers Deposition of Ni-Ti powder on Ti plate using High power Laser deposition Manufacturing of a leaf spring Parallel Manipulator with SMA springs CAD modeling of the parallel manipulator Modeling of helical and leaf springs Analysis using ANSYS Analyzing the behavior of SMA springs with respect to temperature Study of the actuation mechanism of SMA springs in 3-DOF parallel manipulator

Shape Memory Alloy It remembers its shape Deformed shape + Heat = Original shape The high temperature causes the atoms to arrange themselves into the most compact and regular pattern possible Example: Copper-Aluminum-Nickel, Copper-Zinc-Aluminum, Iron- Manganese-Silicon and Nickel-Titanium alloys

APPLICATIONS SMA have applications in industries like- Medical: Mending bones, Stent in artries, Eyeglass frames, Tooth clips Military: Nitinol couplers in F-14 fighter planes Safety:  Anti-scalding devices and fire sprinklers Robotics: As an actuator

NITINOL (Ni-Ti) Temperature (K) Young's Modulus (GPa) 294.25 27.17 299.85 24.82 305.35 22.41 310.95 20.06 316.45 25.72 322.05 31.37 327.55 36.96 333.15 42.61 338.75 48.27 344.25 54.88 349.85 61.43 355.35 64.19 360.95 63.16 366.45 62.06 372.05 63.92 377.55 65.78 383.15 67.64 388.75 69.5 394.25 71.36 399.85 70.81 405.35 70.33 410.95 69.78 416.45 69.29 Was discovered in Naval Ordnance Laboratory (NOL), Maryland, USA Ni- 50% , Ti- 50% FACT: Even 0.l wt% variation of composition causes 10 K error of transformation temperature. HIGHLY SENSETIVE TO COMPOSITION!!

SME in NiTinol By change in phase from Martensite to Austenite Monoclinic FCC (Martensite) to BCC (Austenite)

ADVANTAGES Compactness, allowing for reduction in overall actuator size. Very high power/weight ratio comparatively Accessible voltages can accomplish thermo elastic transformation Higher strain recovery Higher strength Noiseless and silent operation High corrosion resistance

LIMITATIONS Heat Dissipation, need Mechanism for cooling Less Stiffness / high Flexibility Relatively 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. )

Rapid manufacturing using lasers (LRM) STEP TOWARDS FEATURE BASED DESIGN & MANUFACTURING EXTENSION OF LASER CLADDING PROCESS Deposition of a metal on another Metallurgical bonds are formed FABRICATION OF PARTS CAD Model Powder Material

Experimental setup CNC Ti Ni Schematic diagram: Powder Feeder Ni + Ti powder Ni Ti Powder Feeder CNC High power Laser 5 axes manipulator with CNC control Argon atmosphere (965 mbar) No moisture!! Closed loop process control Due 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 Laser Marking the trajectory ƛ=605nm Red color laser Nozzle Laser nozzle dia.= 3.29mm Powder feed nozzle dia.=1.96mm Deposition Melting of powder by power laser (IR) ƛ=1080nm Power of laser= 700W Deposition mechanism of Ni-Ti powder on Ti plate

POWER LASER SPECIFICATIONS ƛ=1080nm (IR laser); feed= 4gm/min Ytterbium laser system YLS-2000 A coolant is used for cooling the nozzle. Temperature of nozzle is kept around 21-22 C Maximum power of the laser= 2000W Power during process= 700W Power 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

Modeling & Simulation Helical spring Diameter of spring…………………..D = 1.5mm Wire diameter………………………..d = 0.5 mm Number of turns……………………..n = 40 Length of fully compressed spring….L= 20 mm Leaf spring Rectangular cross section…………..w = 5mm h = 5mm Arc radius…………………………..r = 37.5 mm Parallel manipulator with helical spring Parallel manipulator with leaf spring

Spring simulation.avi

parallel manupulatorsimulation.avi

REFERENCES http://www.stanford.edu/~richlin1/sma/sma.html www.wikipedia.org 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:10.1117/12.364458 Shape Memory Alloy, BTP Report by Saurabh Maghade and Sahil Agarwal.

THANK YOU!! ANY QUESTIONS??