Calibration and Test of Contact Parameters between Chopped Cotton Stalks Using Response Surface Methodology

Abstract

The accuracy of the material parameter settings directly affects the reliability of the results of the discrete element method simulation. It is necessary to calibrate the relevant parameters to obtain accurate discrete element simulation results when separating the cotton stalk particles from the residual film after crushing. The repose angle of the chopped cotton stalk particles was used as the response value to calibrate the contact parameters between particles. Physical tests measured the intrinsic particle and contact parameters between the cotton stalk particles and the contact material, which provided data for the simulation tests. According to the biological structure characteristics of cotton stalk, the discrete element method model of cotton stalk particles was constructed by bonding the elements of nonequal-diameter basic particles. Based on the response surface methodology, the stacking test of particles was simulated. The response model between the contact parameters and repose angle was established, and the effect law of the single-factor terms and interaction terms on the repose angle was analyzed. The optimal combination of contact parameters was obtained through the single-objective and multi-variable optimization methods. Finally, the contact parameter combination was verified by a simulation test of the repose angle. The results showed that the average relative error of the repose angle between the simulation test and the physical test was 1.04%, which verified the accuracy of the calibrated contact parameters and the reliability of the simulation test. These parameters provide a basis for the discrete element simulation study of cotton stalk motion in the separation process of cotton stalks and residual film and the subsequent gas–solid coupling simulation research.

Simulation and Optimization of a Pendulum-Lever-Type Hole-Seeding Device

“…According to the regression model, a response surface diagram between the significant factors was made, where the shape of the response surface reflects the strength of the interaction factors [31]. This paper mainly analyzed the interaction items that had a significant impact (p < 0.05).…”

“…We drew a response surface diagram of the speed of the hole seeder's moving disc and the angle of the moving hole seeder's lever to the three response indicators (Figure 16); we also drew a response surface diagram of the speed of the hole seeder's moving disc and the number of pendulum bearings to the eligibility index Y 1 (Figure 17). According to the regression model, a response surface diagram between the significant factors was made, where the shape of the response surface reflects the strength of the interaction factors [31]. This paper mainly analyzed the interaction items that had a significant impact (p < 0.05).…”

Parameter Calibration of Discrete Element Model for Cotton Rootstalk–Soil Mixture at Harvest Stage in Xinjiang Cotton Field

“…In the simulation test, the cotton stalk and cotton root particle parameters were set the same. According to the experimental measurements and references [12,[25][26][27]32,[41][42][43], the setting range of discrete element parameters in this paper is shown in Table 3.…”

“…The simulation model was established by using the discrete element software EDEM. The intrinsic particle and contact parameters between the cotton stalk particles and the contact material were measured with a physical test method by Zhang [26] and Li et al [27]. Additionally, based on the response surface method, the repose angel test of particles was simulated, obtaining the optimal combination of contact parameters.…”