Jump to main content.

Aerospace and Mechanical Engineering
Adjust Font Size: Normal Large X-Large

Mechanics of Materials Experiments

Professor T. W. Shield

Contact information is on my biography page.

picture of me


Current Research Projects:

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

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.


Ferromagnetic Shape Memory Materials

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

MMTM Apparatus

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.

Results of Magneto-Mechanical Testing on FePd coming soon!

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


Single Crystal Crack-Tip Plasticity

slip lines is a copper single crystal

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.
orientations animation

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

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.

Structural Phase Transformations: Shape-Memory Alloys

wedge microstructure in Cu-Al-Ni

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.
needle microstructure in Cu-Al-Ni

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.
triangle microstructure

Microstructures in Martensites

Microstructures are what makes Shape-Memory materials interesting and complicated. See the research by Kevin Hane on this topic.
fracture in CuAlNi

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

Shape-memory related links:


Current Graduate Students

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

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


Software, Manuals, etc.


Fun


AUTHOR

T. W. Shield, shield@aem.umn.edu

Last Modified: 2010-05-21 at 22:11:38 -- this is in International Standard Date and Time Notation