Fig 1.
Stem diameter distribution of alfalfa in early flowering period.
Fig 2.
Measuring device for static friction coefficient of alfalfa stalk.
Fig 3.
Alfalfa rolling friction coefficient measurement device and force analysis diagram.
(a) Measuring device. (b) Force analysis.
Fig 4.
Measurement device and motion analysis of alfalfa stalk restitution coefficient.
Fig 5.
CTM2050 microcomputer-controlled electronic mechanics universal testing machine.
Fig 6.
Alfalfa stalk compression test.
Fig 7.
Experiment of alfalfa stalk angle of repose measurement.
Fig 8.
Fitting process of angle of repose of physical test.
(a) Physical test angle of repose. (b) Physical test angle of repose fitting line.
Fig 9.
Simulation model of alfalfa stalk repose angle.
(a) Discrete element model of alfalfa stalk. (b) Angle of repose simulation test device.
Fig 10.
Fitting process of angle of repose of simulation test.
(a) Simulation test angle of repose. (b) Simulation test angle of repose fitting line.
Table 1.
Plackett-Burman test value range.
Table 2.
Plackett-Burman test scheme and results.
Table 3.
Significance test of Plackett-Burman test results.
Fig 11.
Pareto chart of Plackett-Burman experiment.
Table 4.
Steepest ascent test scheme and results.
Table 5.
Significant parameter level coding table.
Table 6.
Box Behnken test scheme and results.
Table 7.
Variance analysis of Box-Behnken test results.
Fig 12.
Response surface of alfalfa stalk repose angle.
(a) x1x4. (b) x4x6. (c) x1x6.
Table 8.
Contact parameters of simulation verification test for the repose angle of alfalfa stalk discrete element at primary florescence.