| To provide basic technical parameters and theoretical basis for mechanized handling and the rational use of cassava stalk, such as crushing and returning in the field, gasification use, and promote the sustainable development of the cassava industry, the mechanical properties test of cassava"Huanan-205"which is widely planted in Chinese cassava growing areas was conducted by using universal material testing machine, self-made knife tools and bearing. The main contents and conclusions of the study include the followings:(1) The tensile test under different loading rates on cassava stem with different moisture content and different internode positions was conducted. The results show that:the values of maximum tensile force were within the ranges79.43?385.40,144.16?476.60,179.46?764.92N for the upper, middle and lower intemode positions, and the average values were119.05,287.92,452.87N, respectively. the values of tensile strength were within the ranges10.37?43.09,10.85?37.44,9.95?47.83MPa for the upper, middle and lower internode positions, and the average values were20.27,22.63,25.64MPa, respectively. The values of Young's modulus were within the ranges1028.54?2308.21,985.26?2615.87,904.53?3136.66MPa for the upper, middle and lower internode positions, and the average values were1615.73,1794.35,1884.41MPa, respectively. The effects of tensile rate on maximum, strength and Young's modulus were not significantly. The effect of moisture contents on strength was significantly, meanwhile,it had no significantly effect on maximum force and Young's modulus.The effect of internode positions on maximum force was significantly,and it had no significantly effect on strength and Young's modulus.(2) The axial compression and radial compression test under different loading rates on cassava stem with different moisture content and different inter-node position was conducted.The results show that:in the axial compression test,the values of maximum compression force were within the ranges817.875?3309.744,2912.575?5585.79,3548.05?7802.17Nfor the upper,middle and lower internode positions, and the average values were2187.28,3867.63,5892.03N,respectively.the values of compression strength were within the ranges7.49?15.30,9.76?12.97,10.79?15.74MPa for the upper,middle and lower internode positions, and the average values were10.65,11.97,12.81MPa, respectively. The values of Young's modulus for compression were within the ranges124.6?483.9,120.7?387.5,191.1?399.2MPa for the upper,middle and lower internode positions, and the average values were249.29,270.33,265.35MPa,respectively.The effect of intemode positions on maximum force was significantly,as well as the moisture contents and loading rates had no significantly effect on that. The effect of intemode positions, the loading rates had no significantly effect on strength as well as the moisture contents and internode positions had significantly effect on that.The effect of moisture contents,loading rates and internode positions on Young's modulus were not significantly.In the radial compression test,the values of maximum compression force were within the ranges8176.52?664.89,2329.50?864.95,3406.00?967.62N for the upper,middle and lower internode positions, and the average values were345.40,542.90,662.97N,respectively.the values of compression strength were within the ranges0.70?1.83,0.80?1.83,0.61?1.74MPa for the upper,middle and lower internode positions, and the average values were1.24,1.19,1.09MPa, respectively.The effect of internode positions on maximum force was significantly,as well as the moisture contents and loading rates had no significantly effect on that. The effect of internode positions,moisture contents and loading rates on strength was not significantly.(3) The different cutting tests under different loading rates on cassava stem with different moisture content was conducted.The results show that:in the sliding cutting test, the values of maximum sliding cutting force was within the ranges241.22?1150.32N,and the average value was662.30N; the values of sliding cutting strength was within the ranges1.55?7.51MPa, and the average value was4.20MPa.The effect of sliding cutting angle and blade's inclination on sliding cutting strength was significantly,however,the moisture content and loading rates had no significant effect on sliding cutting strength.In the cutting test, the values of maximum cutting force was within the ranges261.84?1235.64N,and the average value was649.24N; the values of cutting strength was within the ranges1.12?4.99MPa, and the average value was2.17MPa. The effect of cutting angle and loading rates on cutting strength was significantly, however,the moisture content had no significant effect on cutting strength.(4) The bending test under different loading rates on cassava stem with different moisture content and different internode positions was conducted. The results show that:the values of maximum bending force were within the ranges114.74?576.63,341.271144.44,685.49?1729.89Nfor the upper, middle and lower internode position, and the average values were329.50,699.41,1187.78N,respectively.the values of bending strength were within the ranges9.45?15.82,10.69?17.65,12.13?18.52MPa for the upper,middle and lower internode position, and the average values were12.90,13.59,15.26MPa,respectively.The values of Young's modulus for bending were within the ranges123.94?427.42,127.56?308.15,80.55?256.21MPa for the upper, middle and lower internode position, and the average values were295.45,209.12,150.61MPa,respectively.The effect of bending rates on maximum force and Young's modulus were significantly, and the effect on bending strength was not significantly, The effect of internode positions on maximum force, bending strength and Young's modulus were significantly. The moisture contents had significantly effect on maximum force and Young's modulus, but had no significantly effect on bending strength. |
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