Study On Viscoelastic Behaviors And Simulation For Alfalfa Baling

To treat the compression theory for herbage material, alfalfa with moisture content 17% is compressed on baling test board. Stress relation and engineering compression experiments are conducted in different cross-area of baling room, compress force, displacement and variety of alfalfa wafer's depth are recorded with virtual instruments data logging system. Viscoelastic model in different cross-area of baling room are obtained, through stress relation experiment data processed with method of successive residuals. The model is generalized Maxwell model constituted of 3 parallel Maxwell elements. Relation modulus and creep compliance are gained on base of the model and the viscoelastic theory, establish the constitutive equation. In Matlab and Simulink platform, simulation model of constitutive equation is found. Simulation on stress relation experiment verifies generalized Maxwell model is appropriate to describe the mechanical behaviors of wafer. To compare the stress relation between wafer of different cross-area, on the same starting point of stress, simulation on stress relation of wafers in different cross-area shows that: stress declines at lowest for model of cross-area 360㎜×460㎜ in time interval 0~3s, in time interval 3~6s, model of cross-area 385㎜×460㎜ declines more faster than other cross-area, after 10 seconds relation of stress, the model of cross-area 510㎜×460㎜ becomes the lowest. That is, determination of compress frequency should take the influence of cross-area into account while designing baler, and vice versa. Simulation of strain-time relation of first wafer in translation process as well as stress-time relation of the entire compress process finds the similar deformation characteristics with realistic deformation of wafer.