Study on mechanical properties of cotton stalks in relation to plant pulling machinery

A study was undertaken to determine the mechanical properties of the cotton stalk in relation to design of cotton stalk pulling machinery. Mechanical properties of the cotton stalk such as hardness, crushing and bending strength were studied. A set-up was developed for the laboratory testing of cotton stalk specimen. It consisted of a tripod made of angle iron and a provision was made to screw a probing ring to it to record the force applied to the specimen. The probing ring was calibrated in the laboratory to record force in Newton (N). Samples of LH-1556 variety of cotton were used and the properties at stalk moisture content of 61% and 55.5% were recorded. Tests were executed at 2.15 mm/s rate of loading till failure occurred. The hardness of cotton stalk varied from 30.12 to 56.14 N and 36.63 to 64.82 N at moisture contents of 61% and 55.5% respectively. The range of crushing strength was 4.61 to 10.11 N/mm² at 61.0% stalk moisture and 4.00 to 13.69 N/mm² at 55.5% stalk moisture. The bending strength of the cotton stalk varied form 29.92 to 87.16 N/mm² at 61.0% stalk moisture 44.37 and 111.88 N/mm² at 55.5% stalk moisture. The range of bending strength was 21.22 N/mm² to 42.85 N/mm² 61.0% stalk moisture and at 55.5% stalk moisture varied from 21.89 to 53.70 N/mm². Statistical analysis showed that stalk moisture content had significant effect on all the mechanical properties studied at 5% level of significance.