EMA 611 Advanced Mechanical Testing project ideas
University of Wisconsin
Rod Lakes
Project ideas.
Determine the warp of a bar of square cross section in torsion. Use the optical method of your choice. Compare with the prediction of elasticity theory. Does it matter if the bar has heterogeneous structure?
Determine the viscoelastic Poisson's ratio of a polymer foam. A sequence of video images may be used.
Infer the Poisson's ratio of a material from fringe patterns in bending. Consider the appropriate optical method, e. g. holography or shadow moire.
The lower vibration modes of a cube or short cylinder in resonant ultrasound spectroscopy are dominated by the shear modulus. Can you determine a shape of specimen so that it is easy to determine the bulk modulus from the natural frequency of a vibration mode?
Use wave ultrasound to determine the anisotropic constants of a mineral single crystal such as fluorite or calcite.
Use resonant ultrasound spectroscopy to determine the anisotropic elastic constants of (i) a single crystal jet engine turbine blade sample; (ii) a sample of single crystal shape memory alloy at different stages in the phase transformation. Software in FORTRAN is available but there is a substantial learning curve. How does the anisotropy affect the function of these materials?
Study the ligaments of large animals. Ligaments are nonlinear and they are viscoelastic. What constitutive equation formulation might be most appropriate for the description of ligament? How will the observed properties affect your choice of methods of athletic stretching and conditioning?
Use ultrasound to detect damage in aircraft composites. What kinds of damage are most easily detectable via changes in the wave transmission or reflection characteristics?
Stiffness and strength of wood are known to be related to its density. In wood, how important are strain gradients? Does it matter how the growth rings are aligned with respect to the plane of bending? Does the spacing of growth rings matter? The question of ring spacing is relevant in the context of trees rapidly grown for lumber in fertilized culture in the south. Growth rings can be 1 to 2 cm apart in such cases. Is the quality of such wood good enough? Does the apparent stiffness or strength of a board depend on its thickness?
Use holography or other optical method to explore how heterogeneous is the deformation field in wood. Can that heterogeneity account for the orientation differences seen in the first lab?
Can systems which exhibit snap through buckling also give rise to surprising high stiffness?
See negative stiffness
Study the nodal patterns of a vibrating object using holographic interferometry. The object could be a computer disk drive in which vibration affects the performance. Relate the vibration response to indices of the performance of the device.
Measure the viscoelastic properties of a squash ball, a baseball, a hockey puck, or of a ball used in another sport. How does the actual rebound behavior compare with the rebound predicted based on the measured viscoelastic behavior? How does rebound depend on temperature? Survey the literature on this sport; relate the ball viscoelasticity to the nature and strategy of the sport.
Use the atomic force microscope to create a map of viscoelastic properties on a fine scale. Method development is required here since the instrument as currently configured does not generate such a map.