EMA 630 Viscoelastic Solids class
 
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EMA 630: Viscoelastic solids class, University of Wisconsin
Time and place: Offered, Fall 2003, 2005, 2007, 2009, 2011, 2013, 2015, 2019, 2021. Typical offering: every other year.
Schedule for Fall 2021, TuTh 11:00AM - 12:15PM. ENGR HALL 2239 700 credit is possible; more advanced homework and projects are involved.
Final quiz time to be announced
Textbook: R. S. Lakes, Viscoelastic Materials,
Cambridge University Press, May 2009; ISBN 978 0 521 88568 3
Viscoelastic Materials book outline
References
Ferry, J. D., Viscoelastic Properties of Polymers
Ward, I. M. and Hadley, D. W., Mechanical Properties of Solid Polymers
Coordinator: Rod Lakes, Professor of Engineering
Prerequisites: Mechanics of materials, such as the following.
EMA 303 or ME 306 or BME 315 or MSE mechanical properties class at similar level and senior or graduate status; or else EMA 506 advanced strength of materials or equivalent (such as tissue biomechanics BME 615).
Description: Linear theory of viscoelasticity; non-aging materials; Boltzmann superposition principle; linear functionals; thermodynamic foundations; time-temperature superposition principle; boundary and initial value problems. Applications of viscoelastic materials are to be examined in connection with vibration damping, relaxation of stress in fasteners, creep, droop, and sag in structural members, sound absorption, creep buckling, settlement of foundations, tire mechanics, aircraft materials, and shock attenuation.
Goals: To prepare seniors and graduate students to do advanced analysis and design using materials such as polymers and composites with time and frequency dependent viscoelastic properties or to do research with polymers, composites or biological materials; development of physical insight.
Grading: Grading is based on exams, a project report, and on homework. The scale is 90-100% - A; 85-89% AB; 80-84% B... Reports and homework must be in paper form, not electronic. Report and homework grades will be reduced by 5% per working day (excluding weekends, break, holidays) of additional
delay.
The final exam is scheduled in a central site and will be announced.
Electronics: Bring a calculator to quizzes. Use phones and laptops outside class only. Distraction and multitasking can have adverse, even disastrous, consequences. Do not use phones during lecture: excuse yourself out of the room if you need to use a phone.
Interdisciplinary aspects
Engineering mechanics: All materials exhibit some viscoelastic response. Therefore understanding of elastic response should be supplemented with understanding of viscoelastic response. Materials used in aircraft and spacecraft have viscoelastic response.
Biomedical engineering: Tissues in the body are all viscoelastic. Most tissues exhibit large viscoelastic effects. These effects influence the performance of the tissue.
Materials science: Viscoelasticity results from physical processes such as dislocation motion, grain boundary slip, molecular motions, domain motion, or diffusion. Viscoelasticity is of use as a probe into such processes.
Mechanical engineering: Viscoelastic materials are used for control of vibration in machinery. Viscoelastic damping of materials can reduce noise. Creep and relaxation of materials can affect their performance in machinery.
Civil engineering: Viscoelasticity of soil and other earth materials is relevant to settlement of buildings.
Electrical engineering: Viscoelasticity in piezoelectric materials gives rise to energy dissipation, phase angles, and frequency dependence of properties. Vibration control in computer disk drives improves their performance.
- Course Outline:
- 1 Introduction. Viscoelastic phenomena. Creep. Hysteresis. Decay of vibrations. Viscoelastic solids and liquids. Relaxation. Phase shifts. Wave attenuation.
- 2 Constitutive relations for linear viscoelastic materials. Boltzmann superposition principle Delta functions. Convolutions. Boltzmann superposition integral. Fourier transforms.
Laplace transforms. Effect of temperature. Thermorheologically simple materials.
- 3 Dynamic behavior. Energy storage and dissipation. Phase shifts. Resonance. Wave attenuation. Internal friction.
- 4 Conceptual structure of the theory. Relations among the viscoelastic functions. Approximate interrelations. Physical meaning of the viscoelastic functions.
- 5 Solution of problems involving viscoelastic materials. Correspondence principle. Modified correspondence principle. Non-transform type problems.
- 6 Experimental methods. Transient methods for creep and relaxation. Dynamical methods: subresonant, lumped and distributed resonant. Waves. Temperature effects. Thermal activation.
- 7 Viscoelastic properties of materials. Viscoelastic polymers. Viscoelastic metals. Materials with high viscoelastic damping. Hard and soft biological tissues. Low damping materials. Creep resistant materials.
- 8 Causal mechanisms. Dislocations. Thermo-elasticity. Stress-induced fluid flow; Biot analysis. Snoek relaxation. Granato-Lucke relaxation. Grain boundary motion. Interfaces. Molecular motion in polymers. Phase transformations. Shape memory materials. Piezoelectric relaxation. Processes in biological tissues.
- 9 Viscoelastic composite materials. Structure-property relations. Bounds on properties. Fibrous, particulate, and cellular solids. Foams and honeycombs.
- 10 Applications. Earplugs. Medical diagnosis of disease. Rolling friction. Protection of the human body. Vibration damping. Impact absorbers. Foundation settlement. Tire mechanics. Sound absorption. Ultrasound attenuation in non-destructive testing and in diagnostic ultrasound. Use of residual stress. Instrument mounts. Sway of buildings. Relaxation of fasteners. Gaskets. Concrete viscoelastic properties. Asphalt viscoelastic properties. Viscoelasticity of food products. Spacecraft and satellite performance related to viscoelasticity.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled", Richard Feynman.
In this class we do not add any further burden of dystopia. We will not expect any student to install or use invasive software for any purpose. We will do expect to access your web cam and we do not look at you through it. We do not force intrusive software on your phone and do not track you through your phone. We do not monitor use of apps on your phone. We do not force surveys via robotic software. We do not block you from class.
