Study On Rotary Compression Characteristic Of Chopped Corn Stalks

In recent years, forage shortage is becoming more and more serious due to degradation of grassland in different levels and the rapid development of animal husbandry in China, especially lack of grass in winter. Corn stalks are rich in nutrients and high-quality roughage resource. In China's rural areas, corn stalks, as livestock feed, has a long history. When corn stalks are exploited as livestock feed, the first problem is the low density of its own and they are not easy to collect, transport, storage, which results in low utilization rate. Increasing density by compression is an effective way to solve this problem. Compression can create favorable conditions for further utilization and circulation of corn stalks and improve its economic value.Firstly, the design and formation of rotary compression test bed of chopped corn stalks was completed. The rotary compression test bed of chopped corn stalks is mainly composed of power device, electric control device, silage cylindrical bale bander and measurement system. Electric motor provides a driving force for cylindrical bale bander; electric control device mainly includes frequency converter and switch circuit, which controls the opening and closing of the test bed and motor speed; cylindrical bale bander completes rotary compression as test equipment; measurement system consists of torque measurement system and rotary compression pressure measurement system, and includes two parts, hardware and software. Hardware mainly includes torque sensor, amplifier, strain gauge, static strain measurement system, data acquisition card, computer, etc. Software mainly includes designed LabVIEW virtual instrument test software and XL3403G high-speed static strain test data acquisition and analysis software, which completes data acquisition, processing and saving. In order to install torque sensors, force measuring suspension link, etc. the transmission shaft, bin gate connector, base of bale bander, etc. are also designed and modified, which makes test bed work reliably and meet the test requirements.Secondly, orthogonal test chopped corn stalks rotary compression is designed at different moisture content, different feeding quantity and different speed of squeezing roller. By analyzing the effects that the straw moisture content, the feeding quantity of forage and the speed of squeezing roller have on the rotary compression pressure and power consumption, the affect significance and the primary and secondary relationships of various factors are determined. Using the nonlinear fitting method for the experimental data, the regression model of rotary compression pressure and density is established in the process of rotary compression of chopped corn stalks, meanwhile, the law that rotary compression pressure decreases in nonlinear manner with the increase of moisture content is found. Based on testing results and the forming principle of rotary compression of chopped corn stalks, the compression and forming mechanism of chopped corn stalks is preliminaryly revealed in the rotary compression manner, and the analysis conclusion is verified that the speed of squeezing roller has little impact on power consumption and operating efficiency can be improved by increasing the speed of squeezing roller in the rotary compression mode. The basis for the optimization of rotary compression technology of chopped corn stalks is provided.Thirdly, through the regression analysis of rotary compression pressure and density and the study on the relationship between rotary compression pressure and straw moisture content, the dual equation of rotary compression is established at total moisture content. According to the basic characteristics of stress and strain of chopped corn straws in rotary compression and using the method of combining rheological basic model components, the generalized Maxwell model that describes the rheological properties of chopped corn stalks was established, and the constitutive equation is derived, and the model analysis and testing are carried out from theory and experiment. Based on the constitutive equation, the stress relaxation model and its parameters of the cylindrical bale was obtained through the regression fitting for experimental data, and the effects that moisture content, feeding quantity and speed of the squeezing roller have on model parameters and the stress relaxation effect are analyzed, and the way to improve the state of stress relaxation is proposed, which has theoretical guidance for improving the efficiency of rotary compression and the quality of the cylindrical bale.The main research results provide the theoretical basis for design and development of rotary compression equipment for chopped corn stalks and the optimization of bundling process, which plays an active role for the in-depth study on processing characteristics and methods and technical means of relevant materials and speeding up the eco-efficient use of agricultural fiber materials in promoting.