Residual film recovery machines has have been commonly used in cotton fields in Xinjiang Province in autumn. The plastic film can tear into strips and entangles with impurities on the film during picking. The film with impurities mixture cannot be effectively layered in the conveying process, resulting in low separation of the film with impurities, high impurity content of mulch film, and difficult recycling. This study aims to design the a two-order pin-tooth chain-plate type device for residual film recovery. The multiple tooth collaborative operation was achieved in the continuous picking for the whole residual film in the autumn season. The whole residual film was transported upward to spread on the pin-tooth chain plate. A better separation environment was obtained for the impurity to maintain the effective stratification of membrane impurity in the recovery process. The structure of film film-collecting mechanism was longitudinally arranged with 23 pin-tooth chain plates. The structural parameters of the pin-tooth chain plate were determined to analyze the force in the whole continuous picking of plastic film. The spacing range between the adjacent pin-tooth chain plates was 84mm before the pin-tooth broke the plastic film; The structural parameters were determined for the main, passive rollers, and the stripping ring in the film collecting mechanism; Meanwhile, the angle of the recovery device were also determined, where the angles of the first- and second-order pin-tooth chain plate film collecting mechanism were 125° and 105°, respectively. The kinematics and dynamics analysis showed that the film film-collecting mechanism was used to lift the residual film with impurity. The optimal conditions were clarified to realize the continuous picking, step-by-step spreading, and conveying of the whole residual film. A prototype was trial-produced to conduct the field performance tests. The main influencing factors on the residual film recovery rate of the recovery device were determined as the angular velocity of the picking-passive roller and the operating speed of machinery, according to the principle of picking up film recovery. As the two-order pin-tooth chain-plate type recovery device of the experimental prototype was driven by the front depth limiting roller, the angular velocity of the picking-passive roller was linearly related to the operating speed of the machinery; The first-order film collecting mechanism shared the little range of variation in the ratio of the linear velocity of the tooth end during picking. The operating speed of 0.97 was achieved in by the continuously picking the whole residual film. A single-factor experiment was conducted with the recovery rate of residual film and the rate of containing poles content inside the recycled plastic film as experimental indicators, while the operating speed of the machinery was the influencing factor. The field test showed that the two-order pin-tooth chain-plate type residual film recycling machine was realized for the continuous picking and step-by-step spreading and conveying of the whole film, when the operation speed was within 5.5-7.5 km/h. The average rate of residual film recovery was 89.4%, and the average rate of containing poles was 8.6% in the recovered film. The second-stage nail-tooth chain-plate type device of residual film recovery was enhanced the recovery rate of residual film, whereas, there was the a significant decrease in the rate of containing poles in the recovered film, compared with the commonly- used one. The findings can provide a strong reference for the design of residual film recovery machines.

Soil-engaging components have been severely restricted to the parameters of the water-containing sandy soil. However, it is still lacking in the calibration of simulation parameters. This study aims to clarify the influence of the water content on the contact mechanics among sandy soil particles. Taking the riverside sandy soil as the research object, the Hertz-Mindlin with JKR Cohesion (JKR) contact model was used in the EDEM software. The parameters of sandy soil were then calibrated with four water contents (5%, 10%, 15%, and 20%) using discrete element simulation. The targeted variables of calibration were the static friction coefficient, restitution coefficient, dynamic friction coefficient, and surface energy between sandy soil particles. The simulated angle of the repose of sandy soil particles was taken as the response value. The Box-Behnken response surface method was used for the calibration. A regression model of the angle of repose was also obtained after optimization. It was found that the JKR surface energy shared an extremely significant impact on the angle of repose of sandy soil, and the restitution coefficient had a significant impact on the angle of repose of sandy soil with the higher water contents (15% and 20%), while the static friction coefficient and dynamic friction coefficient had no significant impact on the angle of repose of water - containing sandy soil. The optimal parameters were obtained as follows: for the sandy soil with a water content of 5%, the static friction coefficient between particles was 1.011, the restitution coefficient was 0.41, the dynamic friction coefficient was 0.115, and the JKR surface energy was 0.024 J/m²; for the sandy soil with a water content of 10%, the static friction coefficient between particles was 0.918, the restitution coefficient was 0.532, the dynamic friction coefficient was 0.033, and the JKR surface energy was 0.124 J/m²; for the sandy soil with a water content of 15%, the static friction coefficient between particles was 0.894, the restitution coefficient was 0.835, the dynamic friction coefficient was 0.122, and the JKR surface energy was 1.164 J/m²; for the sandy soil with a water content of 20%, the static friction coefficient between particles was 0.963, the restitution coefficient was 0.893, the dynamic friction coefficient was 0.158, and the JKR surface energy was 3.624 J/m². The relative errors of the angle of repose between the simulation and the physical tests were all less than 5%. The reliability of the model was validated using the intrusion resistance data from the physical pressure-bearing test and the simulation test. There was essential consistency in the resistance trends from the test and the simulation. Once the soil-engaging depth was within the range of 40 mm, the relative errors were all less than 10%. The calibrated parameters were approximately substituted for the real sandy soil. It was also expected to conduct the discrete element simulations between water-containing sandy soil and soil-engaging components. Meanwhile, the findings can also offer the parameter selection under various research, such as the virtual simulation of water-containing soil, the interaction between agricultural equipment and soil, and the performance of soil-engaging components.

Residual films on the sowing layer produced after mulching in Xinjiang farmland, harm the sowing quality and root growth of crops. In this study, a sowing layer residual film recovery machine based on a radial plate arc-shaped nail-tooth roller structure was designed. Meanwhile, the key device structures were designed and the main working parameters were analyzed. Then, taking the working depth, the forward speed of the machine and the rotation speed of the nail tooth roller as the test factors, and the film collection rate and film intertwining rate as the test indicators, the single factor tests and the Box-Behnken response surface tests were carried out to evaluate the performance of the sowing layer residual film recovery machine. Consequently, the results showed that the order of significant factors was the working depth, the forward speed of the machine, and the rotation speed of the nail tooth roller. Besides, the optimal working parameters were determined, which the working depth, the forward speed of the machine, and the rotation speed of the nail tooth roller were 100 mm, 4.8 km/h, and 49.3 r/min, respectively. Moreover, the predicted value of the film collection rate was 69.20%. Finally, the verification test was taken with the optimal working parameter, and the results showed that the film collection rate was 66.84%, and the film intertwining rate was 1.39%. The relative error between the test value and the predicted value of the film collection rate was 3.40%. It indicated that the machine can perform the collection of sowing layer residual films. This study can provide a theoretical basis and reference for the design of new sowing layer residual film machines.