(513a) Strength and Elastic Properties of Corn Stover Stalks

This poster overviews a series of experimental tests that measure the variability of strength and elastic properties of corn stover stalks to better understand the governing behavior during size reduction. Internodal sections of hand cut, and separated corn stalks were selected in three size regimes for this study: (A) 5 mm minor axis diameter x 80 mm stalk length, (B) 10 mm minor axis diameter x 160 mm stalk length, and (C) 15 mm minor axis diameter x 225 mm stalk length. Cyclic bending (0.1 mm increments at 1 mm/min), cyclic radial compression through the minor axis (0.1 mm increments at 1 mm/min), and shearing (1 mm/min) were performed with an electromechanical load frame. The data presented investigates the scale relationships for strength and elastic properties, as well as provides a calibration data set for a structure-informed discrete element modeling (DEM) framework to simulate corn stover comminution. Through a system energy balance, the incremental rotational moments about the stalk’s center during the bending tests are equated to an effective pseudo-rotational spring constant for representation in the DEM approach. Experimentally, scaling relationships are explored for the proportionality limit, and the elasto-plastic transition to an ultimate strength point followed by strain-softening during bending, as well as similar properties under compression and shear forces. This fundamental data set provides a rich understanding for the damage and fracture of corn stover under different failure modes which will help inform and support further large-scale particle deconstruction population balance modelling studies to understand comminution behavior in pilot scale mills.