Tensile Strength of Safflower Stalk as Affected by Moisture Content, Stalk Region and Loading Rate

Abstract

Information on the physical and mechanical properties of safflower stalk is important for the design of machines such as mowers, balers and choppers. The research was conducted in order to determine tensile strength of safflower stalk as a function of moisture content, stalk region, and loading rate. The experiments were conducted at four moisture contents (9.98, 17.85, 26.37 and 38.75% w.b), three stalk regions (bottom, middle, and top) and three loading rates (5, 10 and 20 mm/min). Based on the results obtained, the average tensile strength of safflower stalks, at different test conditions, was obtained as 32.31 MPa varying from 11.63 to 87.84 MPa. The tensile strength decreased as polynomial with increasing moisture content and towards the top regions. The tensile strength decreased from 46.79 to 26.56 MPa, 44.16 to 26.16 MPa, and 38.32 to 19.27 MPa for the bottom, middle and top regions, respectively, as the moisture content increased from 9.98 to 38.75%. The tensile strength increased linearly with increases in the loading rate for all the regions. Its values increased from 28.98 to 43.98 MPa and from 23.31 to 32.45 MPa in the bottom and top regions, respectively, as the loading rate increased from 5 to 20 mm/mm.