EMA 611, Advanced Mechanical Testing of Materials
Prior projects
7-Project
Prior projects
Successful class project. Resonant ultrasonic spectroscopy (RUS) was used to detect yielding in steel bolts. It was possible to distinguish as received bolts from bolts deformed by over-tightening.
Successful class project. The holographic image segment contains time average fringes for torsional vibration of a bar. The central bright fringe represents the nodal line. Higher order fringes are of progressively lower contrast in accordance with theory. The bar is clamped at the upper left and is driven at the lower right.
Successful class project. The holographic image conains fringes for bending of a bar of dense polyethylene foam. The hologram is a reflection type illuminated with white light from a spotlight. The bar is clamped at the right and is loaded in the vertical direction (by a brass weight) at the left. In contrast to the bending fringes shown below, these fringes are vertical or nearly so. The reason is that the observation direction is different. A change in the camera angle reveals a change in the fringe pattern.
Successful class project. The holographic image contains fringes for bending of a plastic bar. The hologram is a reflection type illuminated with white light from a spotlight. The bar is clamped at the right and is loaded in the vertical direction (by a dead weight) at the left. Observe fringes on the clamp support (below). Therefore the support moved. Even though it is made of metal, there are interfaces which move. Observe also the discontinuity of fringe order at the horizontal boundary between the support and the bar. This signifies some slip has occurred during the bending. Observe the movement of the fringes. The camera angle was varied in the vertical direction, for each frame of the animation. Stop the animation if you want, by clicking on the image. The change in fringe order is due to motion orthogonal to the line of sight, in the direction of movement of the camera.
Successful class project. The holographic image contains laser transmission holographic fringes for bending of a wood beam. The supported base of the beam is shown. Kinks in the fringes illustrate the heterogeneous nature of the deformation field due to the growth rings in the wood.
Successful class project. The holographic image shows bending fringes for wood. The weight is on the right. The knot of fringes on the right illustrates the free edge effect known in composite materials. The wood is heterogeneous, and that allows a concentration of deformation on the edge at the right, which is free of applied stress.