Can You Heat Me Now? Brie Frame Sandra Gonzalez Angela Tong Chenny Zhu Department of Materials Science • 3.082 • Advisor: Hao Wang • March 4, 2004 Outline of Presentation Objective Updated Design Potential Materials Proposed Schedule Objective Design and fabricate a heat therapy device for lower back pain with a future use for transdermal drug delivery. Single Component vs. Hybrid Portability Low Cost Modular Temp. Regulation Compact Long Heat Reusability Chemical Electrical Hybrid + + + — — — — + ++ — + + + — — — + + — + + Components of Device Battery High Insulating Layer Heating Core Outer Covering Body Battery Device Placement Heating Device Heating Core Potential Materials Tetradecanol Ethylene Carbonate 2,6-Di-tert-butylphenol Cis-Cyclohexane-1,2dicarboylic anydride Benzylideneacetone Sodium Acetate Insulating Material Potential Materials COHRlastic Solid Silicone Rubber Thermally Conductive R10404 Low Thermal Conductivity 0.0037W/mK Very Thin R10480 Low Thermal Conductivity Flexible Cotton Low Thermal Conductivity 0.03 W/mK Neoprene Insulwrap Quilts from American Acoustical Products Battery Sanyo Batteries Lithium Polymer: UPF574199 high energy density both by volume and by weight, flat and flexible not as much total energy available per battery Li-ion Rechargeable: UR18650H, UR18650F highest energy densities of the fifteen batteries surveyed less total energy than lithium polymer, round casing Saft Batteries Li-ion Rechargeable: MP176065 and others highest total energy available per battery, flat casing big and bulky, rigid casing, low energy density Switch Potential Switches Polymer Thermal Switch Polymer matrix with conductive particles interspersed When cooled, matrix becomes compact, particles touch and form electrically connected network When heated, matrix expands, connected network breaks Bi-metallic Switch Two metals with different expansion coefficients laminated together When heated, one expands more than the other, which causes it to bend and either open or close the circuit Integrated Circuit – Programmable Thermostatic Switch Circuit where temperature setting can be controlled by adding resistors Wire Tensile Testing Ni80Cr20 Ni60Cr40 High Resistance Strong Cross-sectional area = 1.26x10-3 sq. in. Wire Tensile Results for Ni60-Cr40 Stre ss-Strain Curve for Ni60-Cr40 Wire 120000 Stress (psi) 100000 80000 60000 40000 20000 0 0 0.1 0.2 0.4 0.3 0.5 0.6 0.7 Strain Ultimate force withstood: 135 pounds Ultimate Tensile Strength (UTS): 107,432 psi Elastic Modulus= (61,674-15,915) psi / (.1388-.1042) = 1,322.5 ksi Total Elongation=1.9 in. Wire Tensile Results for Ni80-Cr20 Stress-Strain NiCr 80:20 140000 120000 100000 Stress 80000 60000 40000 20000 0 0 0.1 0.2 0.3 0.4 0.5 Strain Ultimate force withstood: 160 pounds Ultimate Tensile Strength (UTS): 127,300 psi Total Elongation=2.6 in. 0.6 0.7 0.8 0.9 1 Proposed Schedule Feb 2004 ID Task Name Start 2/1 1 Formal Design Review Presentation 2 Obtaining Materials 3/11/2004 3/11/2004 2/5/2004 3/18/2004 3 Wires 3/2/2004 3/4/2004 4 PCM 3/2/2004 3/11/2004 5 Thermal Switch 3/9/2004 3/11/2004 6 Polymer Gel 3/9/2004 3/11/2004 7 Insulating Material 3/9/2004 3/16/2004 8 Battery 3/9/2004 3/16/2004 9 Outside Material 3/9/2004 3/16/2004 Wire Coating 3/9/2004 3/16/2004 3/9/2004 3/18/2004 10 11 Processing 12 Polymer Gels 3/11/2004 3/18/2004 13 Wire Coating 3/11/2004 3/18/2004 3/2/2004 4/1/2004 14 Testing Materials Mar 2004 Apr 2004 May 2004 Finish 15 Wire 3/2/2004 3/9/2004 16 PCM 3/4/2004 3/18/2004 17 Thermal Switch 3/16/2004 3/25/2004 18 Polymer Gel 3/18/2004 4/1/2004 3/18/2004 4/6/2004 19 Prototype Assembly 20 Initial Prototypes 4/6/2004 4/6/2004 21 Testing and Troubleshooting Prototype 4/6/2004 5/6/2004 22 Last Day of Lab Work 5/6/2004 5/6/2004 23 Final Presentation/Posters Due 5/13/2004 5/13/2004 2/8 2/15 2/22 2/29 3/7 3/14 3/21 3/28 4/4 4/11 4/18 4/25 5/2 5/9 5/16