Cutting force and cutting energy investigation of sesame stalk at quasi-static cutting process

Abstract

Due to the high loss of sesame seeds during harvesting, the cutting of stalks is an important process in sesame harvesting and there is an essential need for complementary information on the cutting properties of sesame stalk. This study primarily aimed to investigate and analyze the important cutting parameters of cutting force and specific cutting energy of sesame stalk in quasi-static cutting process. The samples were taken from the bottom, middle, and top regions of the stalk and tested at moisture content levels of 15%, 30%, and 60% on wet basise. Shearing tests were performed at four cutting speeds (1, 2, 3, and 4 mm min^-1) following a factorial experiment in a completely randomized design. The effects of stalk moisture content, stalk cutting position, and cutting speed on the mentioned traits, as well as the interaction between moisture content and stalk cutting position on specific shear energy, were significant at the 1% probability level. The results indicated that increasing stalk moisture content from 15% to 60%, cutting speed from 1 to 4 mm min^-1, and moving from the bottom to the top of the stalk, reduced the specific shear energy and cutting force of sesame stalks. The maximum specific shear energy was 31.08 J mm^-2, and the maximum cutting force was 1039 N, both at a cutting speed of 1 mm min^-1. The results also showed that in the first, second and third stages of sesame stalk cutting, the stalk resistance to blade penetration values are differnet and the sesame stalk has different resistance to the movement of the cutting blade inside the stalk.