MAE 262 – Mechanics of Intelligent Materials and Systems
Prerequisites:Fundamental material behavior including knowledge of stress, strain, and elastic constitutive behavior.
Content: In-depth overview of three classes of multi-field coupled materials and applications that will include electro-mechanical coupling (piezoelectricity and electrostriction) and thermo-mechanical coupling (shape memory effects) as found in crystals, ceramics, metals, and polymers. Discussion of material, actuator, and sensor selection for applications that include energy harvesting, sensing, and actuation. The approach will include a combination of mechanics and materials.
Details: Multifunctional materials, like muscle, change shape under an externally applied field. That field can be thermal, electric, or magnetic. Electro-active polymers (EAPs) are a class of materials often referred to as artificial muscle. They are highly compliant and change shape when a voltage is applied. They have been used to create small walking bots and as large stroke muscle type actuators. The first third of the course addresses EAPs and their applications. Piezoelectric ceramics are much stiffer than EAPs. They produce smaller strain and much larger force in response to applied voltage. They are used in sonar, medical ultrasound, energy harvesting, and actuation. The second third of the course will introduce piezoelectricity and its application to sensors and actuators. Shape memory alloys, the most common being NiTi, are metals that display superelastic behavior in certain temperature ranges and shape memory behavior in other temperature ranges. They are used to produce stents to open blocked arteries, and in a range of actuator applications. The final third of the course will introduce shape memory alloys and their applications.
Electro-active Polymer Materials – Prof. Q. Pei
Hour 1 Introduction to polymers relevant to electro-mechanical transduction.
Hour 2 Ionic polymer-metal composites.
Hour 1 Conducting polymers.
Hour 2 Field-activated polymers.
Hour 1 Dielectric elastomer fundamentals (Maxwell, linear modeling, basic materials) and effects of prestrain.
Hour 2 Advanced DE materials.
Lecture 4 – Modeling dielectric elastomers.
Hour 1 Hyperelasticity and electromechanical coupling (Maxwell equation).
Hour 2 Electromechanical instability and prestrain.
Hour 1 Compliant electrodes.
Hour 2 Soft actuator designs.
Hour 1 Applications, including artificial muscle based robots.
Hour 2 Energy harvesting / review of electroactive polymers.
Ferroelectric materials – Prof. C.S. Lynch
Lecture 7–Introduction to Piezoelectric Materials.
Hour 1 Overview of ferroelectrics: Material behavior and applications.
Hour 2 Review of Fundamentals (index notation, vectors, and tensors).
Lecture 8 – Material symmetry, piezoelectric constants, and open circuit vs. short circuit elastic constants.
Week 5 Piezoelectric composites.
Midterm on Electroactive Polymers and piezoelectric materials.
Lecture 9 Piezoelectric beam actuators.
Hour 1 Unimorphs, bimorphs, rainbows, and moonies.
Hour 2 Beam equations with piezoelectric layers.
Lecture 10 Piezoelectric beam actuators continued.
Hour 1 Moment, curvature, and displacement.
Hour 2 Example problems.
Lecture 11 Dynamic behavior of piezoelectric beams.
Hour 1 Natural frequency of a cantilever beam.
Hour 2 Forced vibration using piezoelectric layers.
Lecture 12 Structural applications.
Hour 1 Shape control, vibration control.
Hour 2 Vibration energy harvesting, piezoelectric motors.
Shape Memory Alloys – Prof. G.P. Carman
Hour 1 Shape memory alloy SMA history and applications.
Hour 2 Crystallographic description of SMA.
Hour 1 Energy balance and transformation temperatures.
Hour 2 Shape memory response.
Hour 1 Psuedoelastic response.
Hour 2 Nitinol and compositional sensitivities.
Hour 1 Experimental curves and measurements.
Hour 2 Constitutive relation development.
Hour 1 Reduction to 1-D problem.
Hour 2 Shape memory example.
Hour 1 Psuedoelastic example.
Hour 2 Review for exam.
Final Exam on Ferroelectrics and Shape Memory Alloys