Maize stalk failure often typically involves Brazier buckling, but the initiation of failure is poorly understood. In hollow tubes, buckling is controlled entirely by cross-sectional ovalization, but the septated, pith-filled stems of maize stalk are more complex. To study the initiation and progression of the stem failure, we created a measurement system consisting of a camera integrated with a universal testing machine to simulate and document a 3-point bending test on individual stalks. The camera moves in parallel with the loading anvil, thus preserving a consistent viewing perspective. The universal testing machine triggers the camera and records the time stamp of individual photographs. This system collects force, deformation, and image data during the test. Custom software was used to track landmarks on the stem, thus allowing a consistent cross-section to be analyzed during testing, even if substantial rotation of the stalk occurs during bending. Results revealed two failure mechanisms. First, localized buckling of the stem increased mechanical stresses, which caused tissue failure and collapse. Second, tissue failure sometimes occurred spontaneously, which tended to initiate buckling behavior. Thus, whichever mode is weakest in a particular stalk will happen first, and the remaining mode will appear as part of the structural collapse process. This information provides a more complete understanding of maize stalk failure.
University / Institution: Brigham Young University
Format: In Person
SESSION B (10:45AM-12:15PM)
Area of Research: Engineering
Faculty Mentor: Douglas Cook