Viscoelasticity links
EMA611
EMA630
BME615
BME315
Think logarithmic
Phase delta. Stress vs. strain in sinusoidal loading. Meaning of the loss tangent.
Spring damper model which gives single exponential relaxation.
Single exponential relaxation E(t) on a log scale.
Exponential and power law, linear scale.
Exponential and power law, log scale.
Creep vs. relaxation, direct Stieltjes construction
Demonstrations.
Stiffness / loss plot.
QLV
nonlinear superposition
Broadband viscoelastic spectroscopy (BVS)
Instrument diagram
slow
fast
Instrument
Instrument functions
Instrument chamber
Resonant Ultrasound Spectroscopy (RUS)
RUS diagram
setup image,
scan on scope,
Maynard pdf of Physics Today article by Julian Maynard
Videos of vibration modes of isotropic cylinder with length equal diameter, after T. Jaglinski
torsion,
shear,
bend,
mixed bend,
flattening,
symmetric axial.
Industrial non destructive testing
Measure damping via RUS, pdf,
shear mode RUS pdf after Lakes.
Viscoelastic composites
Composite Structure.
Bounds on composite stiffness.
Stiffness loss map, theory
Stiff-loss shape
Stiff-loss stiff phase
Viscoelastic Materials
Causal mechanisms
PMMA (Polymethy methacrylate) Viscoelasticity. A broadband spectrum.
Indium-Tin Viscoelasticity. A broadband spectrum.
InSn and models
Stiffness / loss plot
Stiffness / loss plot: new materials.
Tissue properties.
QLV;
experiment.
Applications
Case study: Baby heads improper treatment.
2,
3.
Misshapen head reshaped
Baby helmet for head reshaping