Study And Simulation On Creep Behavior Of Alfalfa

Alfalfa is a kind of viscoelastic agricultural fiber material. The creep properties of it have important impacts on the characteristics of products compressed, processing technology and optimization of compressing equipments. Therefore, the creep properties of Alfalfa were studied through the experiments and theoretical analysis, in this paper. The factors, which mainly influenced the Alfalfa's creep, were tested and after analyzing the results, the relationship between factors and creep parameters were found out. Then, based on virtual prototyping technology, the paper developed a virtual model that used for studies, the conclusions were as follows:(1) The best compression density range of Alfalfa was found out through analyzing loading stages during the creep course of it. In respect to different initial densities, the range is 200~300kg/m3.(2) By the principle of Boltzmann superposition, integral theory, the Taylor series expansion and method of multiple regression analysis, the creep characteristics of Alfalfa in the high-density compression process at loading stages, were measured and analyzed. Meantime, the problem that only under the instant certain stress could the creep characteristics be studied was resolved and the creep equation was discovered.(3) The creep rules of Alfalfa under different initial densities, loading and moisture content were found out. Then, the rheological model at different creep courses and phases that pressure was a constant, were established, it was the Burgers model that had four components. Meanwhile, the paper analyzed the effects that initial density, loading and moisture content have on the creep characteristics. The results showed that when the moisture content was certain and the load didn't change, the greater initial density was the smaller the creep deformation was; As the load and initial density were constants, the higher moisture content was, the greater creep deformation was.(4) Based on virtual prototyping technology, the virtual prototype rheological model of Alfalfa were established. Comparing simulation results with experimental ones, the ADAMS simulation creep model was reasonable and reliable. With further analysis of the model, the rules that the components strains in the model changed with time were obtained.