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Mechanics of Materials Experiments Professor Emeritus T. W. Shield Contact information is on my biography page.

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Previous Research Projects:

My research program had focused on understanding the mechanics of a few types of novel material behaviors:

• Ferromagnetic Shape Memory Materials
  • Construction of a Magneto-Mechanical Testing Machine
  • Investigation of FePd Ferromagnetic Shape Memory Behavior
• Single Crystal Crack-Tip Plasticity
  • Stationary Notch Tip Plastic Fields
  • Growing Crack Tip Plastic Fields
• Structural Phase Transformations: Shape-Memory Alloys
  • Orientation Dependence of the Transformation Behavior of Cu-Al-Ni
  • Thermal Effects in NiTi Wires
  • Needles in CuAlNi
  • Fracture of CuAlNi

Publications

The abstracts of my publications are in a Searchable Database. Send me an email if you would like a PDF version of any of my recent papers. Publications related to the topics above are listed below under each topic.

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Ferromagnetic Shape Memory Materials

These are materials that are both magnetic and undergo a structural phase (shape-memory) transformation.

Magneto-Mechanical Testing Machine (MMTM) Construction is almost complete of a Magneto-Mechanical Testing Machine (MMTM) that will allow these materials to be studied in detail.

FSM Publications

1. Cui, J., Shield, T. W., and James, R. D., "Phase Transformation and Magnetic Anisotropy of an Iron-Palladium Ferromagnetic Shape Memory Alloy," accepted for publication in Acta Materialia, 2003.
2. Shield, T. W., "A Magneto-Mechanical Testing Machine for Ferromagnetic Shape-Memory Alloys," Review of Scientific Instruments, 74(9), pp. 4077-4088, 2003. 31.
3. Shield, T. W., and Cui, J., "Magneto-Mechanical Behavior of a Ferromagnetic Shape Memory Alloy: Fe3Pd," Proceedings of SPIE, 4699, March, 2002.
4. Tickle, R., James, R. D., Shield, T. W., Wuttig, M., and Kokorin, V. V., "Ferromagnetic shape memory in the NiMnGa system," IEEE Trans. Magnetics, 35, pp. 4301-4310, 1999.

Collaborators

• Professor P. H. Leo, AEM Department
• Professor R. D. James, AEM Department
• Professor Manfred Wuttig, University of Maryland
• Dr. J. Cui, University of Maryland (Minnesota Ph. D., 2001)

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Single Crystal Crack-Tip Plasticity

	Measurement of Plastic Strains near a Notch Tip in a Copper Single Crystal The plastic strain field surrounding a crack (100 micron notch) in a single crystal of copper was measured using microscopic moire interferometry.
	Orientation Dependance of the Plastic Slip near Notches in Ductile FCC Single Crystals Many different orientations of notches in single crystal have been studied

Collaborators

• Professor Walter Drugan, University of Wisconsin, Madison.
• Professor Wendy Crone, University of Wisconsin, Madison

Single Crystal Plasticity Publications

1. Crone, W. C., Shield, T. W., Creuziger, A., and Henneman, H., "Orientation Dependence of the Plastic Slip near Notches in Ductile FCC Single Crystals," to appear in the Journal of the Mechanics and Physics of Solids, 2003.
2. Crone, W. C., and Shield, T. W., "An Experimental Study of the Effect of Hardening on Plastic Deformation in Metallic Single Crystals," Journal of the Mechanics and Physics of Solids, 51(8), pp. 1623-1647, 2003..
3. Crone, W. C., and Shield, T. W., "Experimental Study of the Deformation Near a Notch Tip in Copper and Copper-Beryllium Single Crystals," Journal of the Mechanics and Physics of Solids, 49, pp. 2819-2838, 2001.
4. Shield, T. W., "An Experimental Study of the Plastic Strain Fields near a Crack Tip in a Copper Single Crystal During Loading," Acta Metallurgica, 44(4), 1996, pp. 1547-1561.
5. Shield, T. W., and Kim, K.-S., "An Experimental Study of Plastic Deformation Fields near a Crack Tip in an Iron-Silicon Single Crystal," Journal of the Mechanics and Physics of Solids, 42(5), 1994, pp. 845-873.

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Structural Phase Transformations: Shape-Memory Alloys

	Orientation Dependence of the Transformation Behavior of Cu-Al-Ni Tension specimens of a shape-memory alloy of Copper, Aluminum and Nickel are used to observe the pseudoelastic behavior of these materials. Observations are made of the microstructure that forms and this is correlated to the mechanical behavior. Images and Movies of microstructure formation from paper [4] are here.
	Needles in Martensites A common microstructural element observed in microstructures involving compound twins are needles that end at interfaces. Preliminary work with R. D. James and R. Kohn (Courant Inst.) was presented at ICOMAT-95. Click on the image for a summary of this work.
	Microstructures in Martensites Microstructures are what makes Shape-Memory materials interesting and complicated. See the research by Kevin Hane on this topic.
	Fracture of CuAlNi Shape-Memory Single Crystals The fracture properties of single crystals of CuAlNi, a shape memory alloy, were studied by G. M. Loughan (Vasko) as part of her Ph.D. thesis work.

Shape-Memory Publications

1. Loughran (Vasko), G. M., Shield, T. W., and Leo, P. H., "Fracture of Shape Memory CuAlNi Single Crystals," International Journal of Solids and Structures, 40(2), pp. 271-294, 2003.
2. Vasko, G. M., Leo, P. H., and Shield, T. W., "Prediction and Observation of Crack Tip Microstructure in Shape Memory CuAlNi Single Crystals," Journal of the Mechanics and Physics of Solids, 50, pp. 1843-1867, 2002.
3. Hane, K. F., and Shield, T. W., "Microstructure in a Cubic to Orthorhombic Transition," J. Elasticity, 59, pp. 267-318, 2000.
4. Hane, K. F., and Shield, T. W., AEM Report 1997-8. "Microstructure in the Cubic to Trigonal Transition," Materials Science And Engineering A, A291, pp. 147-159, 2000.
5. Hane, K. F., and Shield, T. W., AEM Report 1997-7. "Microstructure in the Cubic to Monoclinic Transition in a Titanium-Nickel Shape Memory Alloy," Acta Meterialia, 47(9), pp. 2603-2617, 1999.
6. Hane, K. F., and Shield, T. W., "Microstructure in a Copper-Aluminum-Nickel Shape Memory Alloy," Proc. R. Soc. Lond. A, 455, pp. 3901-3915, 1999.
7. Hane, K. F., and Shield, T. W., AEM Report 1997-9. "Symmetry and Microstructure in Martensites," Phil Mag. A, 78 (6), 1998, pp. 1215-1252.
8. Shield, T. W., Leo, P. H. and Grebner, W. C. C., "Quasi-Static Extension of Shape Memory Wires under Constant Load," Acta Metallurgica, 45 (1), 1997, pp. 67-74.
9. Shield, T. W., "Orientation Dependence of the Pseudoelastic Behavior of Single Crystals of Cu-Al-Ni in Tension," Journal of the Mechanics and Physics of Solids, 43(6), 1995, pp. 869-895.
10. Leo, P. H., Shield, T. W. and Bruno, O. P., "Transient Heat Transfer Effects on the Pseudoelastic Behavior of Shape-Memory Wires," Acta metallurgica, 41(8), 1993, pp. 2477-2485.

Collaborators

• Professor P. H. Leo, AEM Department
• Professor R. D. James, AEM Department

Shape-memory related links:

• The shape-memory transformation is a type of martensitic phase transformation. For more information on Martensites see What Are Martensites?, by Jim Sethna
• Here is a nice source of many SMA Links.

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Previous Students

• Yiming Wu, Ph.D., 2010
• Ganesh Borra, M.S., 2010
• John Messier, M.S.
• Bryan Henneman, M. S.
• Ryan Wold, M. S.
• Kevin Hane: ``Microstructures in Thermoelastic Martensites'', Ph. D. 1998
• Professor Wendy Crone: ``Experimental Investigation of the Deformation near a Notch Tip in Metallic Single Crystals," Ph.D. 1998
• Dr. Galyna Vasko, "Interaction of Phase Transformation and Fracture of a CuAlNi Single Crystal," co-advised with P. H. Leo, Ph. D. 2001

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ACKNOWLEDGMENTS

My research is or has been supported by The National Science Foundation, The Office of Naval Research , The McKnight Foundation, National Institutes of Health, The University of Minnesota Graduate School and the AEM Department.

This material is based in part upon work supported by the National Science Foundation under Grant No. 9800245

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation

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Software, Manuals, etc.

• Software I've written, but this is all rather old now....
  • GFx Old X-Windows manual, but is still a good reference for GfQt
  • PSALL Produces Postscript from Images with GF Plot overlays.
  • Retex script to automatically reTeX and redisplay with Xdvi a file when it is modified
  • Qt Based Programs
    • Slide Show How I give presentations written in LaTeX using a computer.
    • Truss Solver Used for Aerospace Structures I
    • Xorient Used for reducing data from X-Ray Microdiffraction
  • Zip/Jazz Utiliies for Irix 5.3
• Manuals
  • LaueX Software manual is on line.
  • Crystal Grower Controller Usage For our Crystal Grower
  • Procedures and Manuals SOP, Crystal growth and Instron
• Lots of information on crystallography is available on the www.

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Fun

• Current Earth Simulation a view from straight above here.
• Images of Comet P/S-L9 collision with Jupiter (local copy)
• How about an award winning photo of a frog that I took? It won best nature photo at The Croaker Festival held in Oriental, NC, in July 2003.

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AUTHOR

T. W. Shield, shield@umn.edu

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Last Modified: 2022-09-23 at 10:33:00 -- this is in International Standard Date and Time Notation