Contact: Prof. Zehnder, atz2@cornell.edu
Cracks in brittle materials grow primarily along a surface that is perpendicular to the direction of maximum principal stress. In two dimensions this leads to curving crack paths that are well understood. However, in three dimensions the evolution of the fracture surface is less well understood due to contact between crack surfaces and the fact that different parts of the crack surface may be under different stress conditions driving the crack in different directions. I am interested in the competition between spiral and flat fracture in notched bars loaded in torsion. Rudimentary experiments performed in my lab show that as the depth of the notch increases the mode of fracture switches from spiral to flat. This project will involve the design and execution of a series of experiments aimed at mapping out this transition and documenting the fracture paths. The experimental work is expected to take a semester, but the project can be extended to include computational simulations in the 2nd semester if the student is interested and has the appropriate background.
Qualifications of Student: MAE 3250 AND 3272 (or equivalents) for 1 semester experimental project, + MAE 4700 for two semester experimental/computational project.