PowerPoint Presentation

Shear Stress Sensor Using Cholesteric CrystalsGroup #3

Group MembersMatthew Carmichael, FSUTyler Elsey, FSULuiz Paes, UNIFEI

Graduate AssistantMatthew Worden

SponsorsDr. Dickinson , Eglin AFRLDr. Oates, FAMU & FSU COE

2/20/2013eng.fsu.edu/me/senior_design/2013/team31

OVERVIEWProject Scope and ObjectivesTheoryTechnical ApproachFinal Design Programming NeededSchedule

2Need Statement & Project ScopeNeed StatementNeed in the market for a shear stress sensor that can be used outside the labProject ScopeCreate Testing ApparatusDetermine if cholesteric crystals are able to measure shear stress

3Cholesteric Crystals4

Originally discovered in cholesterolHelical StructurePitch varies with the boundary conditions i.e. electricity or forcesLiquid Crystals made easily from 3 powdersPolymer form made through many time intensive processes

Technical Approach5

Assume no slip condition for liquid crystal testingBluLoop Fiber Optic LightSpectrometer: 200-1100 nm 2048 pixelsLinear Servo Motor:1 step = 1/64Load cell:10NFinal Design6

Programming7LabViewCorrelation between load and voltage with load cellLoad cell, spectrometer need to start at the same time record informationMATLABCreate method to review time resolved dataFilter spectrum from reference spectrumFind equation that relates load to wavelength

Labview8

Matlab9

Simulation10 FEM (Finite Element Method)Pressure - Sine Load -0.5 sin ((4/L)*x) Pa - top

0.5 sin ((4/L)*x) Pa - bottom

xyStress YY (Pa)Y Coordinate (m)

X Coordinate (m)Pressure Error Sigma YYX Coordinate (m)Error (Pa)

Simulation11 FEM (Finite Element Method)Pressure - Sine Load -0.5 sin ((4/c)*x) Pa - top

xyThin film - L=2000 (c)

Stress YY (Pa)Y Coordinate (m)X Coordinate (m)

Simulation12 FEM (Finite Element Method)Shear - Cosine Load -0.5 cos ((4/L)*x) Pa - top

0.5 cos ((4/L)*x) Pa - bottom

xyStress XY (Pa)Y Coordinate (m)X Coordinate (m)Pressure Error Sigma XYX Coordinate (m)Error (Pa)

Simulation13 FEM (Finite Element Method)Shear - Cosine Load -0.5 cos ((4/c)*x) Pa - top

xyThin film - L=2000 (c)

Stress XY (Pa)Y Coordinate (m)X Coordinate (m)

Schedule14

Summary15-Shear stress device measurement was fabricated

-Labview and MATLAB interface is ready for experiments

-Testing samples have been made

-Next steps

Testing and analysis

Vary testing conditions and test polymer form of Cholesteric Crystals

Questions/Comments16