Experimental Study On Stress Relaxation Characteristics Of Silage Corn Straw In Round Bales

In order to obtain the stress relaxation characteristics of silage corn straw round bales,a test-bed is developed in this papper for measuring the stress of silage corn straw round bales.Taking the silage corn straw round bales when leaving the compression chamber of the baler as the research object,using the method of combining theory and experiment,the stress relaxation characteristics of silage corn straw round bales were studied with the test factors of the tightness,feeding times and water content.The effect of experimental factors on stress relaxation of silage corn straw round bales was studied,and stress relaxation model of round bales of silage corn straw were obtained.The main research contents are as follows:(1)According to the test environment and test requirements,a round bundle force test-bed is developed.The data acquisition system can display the changes of test data in real time and store them for the processing and analysis of test results.(2)Through the single factor experiment,the main factors that affect the stress relaxation of silage corn straw round bale,as well as the influence rule and value range of the main factors were obtained.At the same time,the stress relaxation model of silage corn straw round bale is obtained.It is found that the stress relaxation model of silage corn straw round bale can be expressed by the five element equation of two Maxwell elements and one equivalent spring in parallel.(3)Through the response surface method,the regression mathematical model of the test index is obtained,and the influence law of each factor on the rapid stress decay time and the equilibrium modulus of elasticity is obtained.The main and secondary order of the influence of each factor on the rapid stress decay time and the equilibrium modulus of elasticity is:moisture content>the tightness of the web>the feeding times.The results show that when the feeding times are one,the moisture content is 72%,and the tightness of the web is four,the stress rapid decay time and the equilibrium modulus of elasticity of the corn straw round bale are the shortest.