Experimental Study On Compressive And Stress Relaxation Characteristics Of Solid Sweet Sorghum Straw

In order to obtain the compression and stress relaxation characteristics of sweet sorghum straw compression process.Based on the multi-function electronic creep relaxation tester,an adjustable compression unloading device was designed.Taking sweet sorghum straw as the research object,the combination of theoretical research and experiment was used to study the compression and stress relaxation characteristics under different compressive density,moisture content,cutting length and compression speed.The effects of various experimental factors on the compression and relaxation process of sweet sorghum straw were discussed,and the corresponding mathematical models were established.The main research contents are as follows:(1)A compression model of sweet sorghum straw compression process was established through experiments and theoretical analysis.Different moisture content,compression density,cutting length and compression speed and the relevant parameters of the compression model at different levels were obtained.The effects of various factors of compression process on compression characteristics and specific energy consumption were analyzed.(2)A stress relaxation model of the relaxation process of sweet sorghum straw was established through experiments and theoretical analysis.The stress relaxation curve of the sweet sorghum relaxation process was found to be expressed by a five-element Maxwell model in which two Maxwell units were combined in parallel with one equivalent spring.Meanwhile,the influence of various experimental factors on the stress relaxation characteristics was obtained.(3)A regression mathematical model of influencing factors and experimental indicators was established through the parameter optimization experiment.And the influence of various factors on specific energy consumption,rapid decay time and equilibrium elastic modulus was obtained.Meanwhile,the primary and secondary factors affecting the specific energy consumption was obtained:cutting length>moisture content>compression density.The primary and secondary factors affecting the rapid decay time was obtained:cutting length>moisture content>compression density.The primary and secondary factors affecting the equilibrium elastic modulus was obtained:cutting length>compression density>moisture content.The specific energy consumption in the compression process was the minimum,stress rapid decay time was the shortest,and equilibrium elastic modulus was the minimum when compression density was 638.05 kg/m3,cutting length 20?30 mm,and moisture content 57%.