Effect of Loading Rate on Mechanical Characteristics of Wheat and Rice Straw

F. A. CHANDIO1,2, C. JI1, A. A. TAGAR1,2, I. A. MARI1, C. ARSLAN1, D. M. CUONG1 and H. FANG1
1 Nanjing Agricultural University, Department of Agricultural Mechanization, College of Engineering, 210031, Nanjing, P. R. China
2 Sindh Agriculture University, Faculty of Agricultural Engineering, Department of Farm Power and Machinery, Tando Jam, Sindh, Pakistan


CHANDIO, F. A., C. JI, A. A. TAGAR, I. A. MARI, C. ARSLAN, D. M. CUONG and H. FANG, 2013. Effect of loading rate on mechanical characteristics of wheat and rice straw. Bulg. J. Agric. Sci., 19: 1452-1458


This study was designed to evaluate mechanical characteristics of wheat and rice straw keeping in view the importance of straw application in the field. Technical data about mechanical properties of straw such as bending strength shearing energy and young's modulus still need to update. These properties were evaluated on three internodes positions (N1, N2 and N3) down from ear at average moisture content of 18.10%. Three loading rates (15, 20 and 25 mm min-1) were employed by TMS- Pro machine with computer program for data acquisition and a steel plate was fabricated for holding straw at different internode’s position. Some other physical parameters like length, diameter and cross sectional area were also measured for the determination of mechanical properties. Results showed that when loading rate increased, bending strength of wheat and rice straw decreased from 23.93 to 7.49 and 15.99 to 7.17 MPa respectively, shearing energy increased from 124.28 to 265.44 and 111.69 to 215.44 mJ respectively, and young’s modulus varied from 1.20 to 0.22 and 0.72 to 0.20 GPa respectively. The bending strength and young’s Modulus of wheat straw were significantly higher (p<0.05) than those of rice straw whereas the shearing energy had significantly effect of loading rate on rice and wheat straw (p<0.01). It was concluded that more energy can be saved by harvesting and threshing machines with decreasing the loading rate on wheat and rice straw toward the first, second and third internode’s positions which will be helpful in designing of wheat and rice straw equipment, harvesting machines and tillage implements.

Key words: bending strength; shearing energy; Young’s modulus; rice and wheat straw

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