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The study of cotton stalk extraction resistance provides important parameters for the design of cotton stalk harvesting machinery. To investigate the effects of soil moisture content, cotton stalk diameter, and extraction angle on the extraction force of densely planted cotton stalks, this paper designs a real-time measurement system based on virtual instrument technology and conducts field tests. The tests were carried out in cotton fields at the First Farm in Aral City, Xinjiang, using the cotton variety “Xiulu Zhong 70”. Single-factor experiments were conducted with extraction angle and stalk diameter as influencing factors. A combined three-factor experiment was performed under the following conditions: soil moisture contents of 21.87% and 26.32%; extraction angles of 25°, 30°, and 35°; and cotton stalk diameters of 8.50–9.00 mm, 10.00–10.50 mm, and 11.50–12.00 mm. The results show that the minimum extraction force is required when the extraction angle is 30°. Soil moisture content significantly affects the extraction force, which increases with stalk diameter. The combined test results indicate that the order of significance of the three factors is as follows: cotton stalk diameter (A), extraction angle (B), and soil moisture content (C). The optimal combination is A1B1C2, corresponding to a diameter of 8.50–9.00 mm, an extraction angle of 35°, and a soil moisture content of 26.32%. Based on comprehensive analysis, the recommended extraction angle range is 30–35°. The proposed system can efficiently complete cotton stalk extraction force tests, and the collected data provide valuable references for the design of cotton stalk harvesting machinery. By appropriately selecting the extraction angle and conducting harvesting under suitable soil moisture conditions, it is possible to reduce power consumption and improve production efficiency.

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.

Using the discrete element method to simulate the interaction between cotton stalks and machinery is an effective approach for analyzing the cotton stalk defibration mechanism and optimizing the structural parameters of cotton stalk defibration equipment. To further improve the accuracy of studies on the interaction between cotton stalk defibration devices and cotton stalks, cotton stalks from typical arid regions in southern Xinjiang were selected as the research object, and a discrete element parameter calibration study was conducted based on the discrete element method. Considering the differences in cotton stalk diameters, two discrete element models of cotton stalks with diameters of 8.5 mm and 10.5 mm were established. Plackett–Burman screening tests and Box–Behnken tests were employed to calibrate and optimize the discrete element contact parameters for cotton stalk models with different diameters. Optimization was carried out using the load responses obtained from mechanical tests of cotton stalks as the target values, and the optimal parameter combinations of the cotton stalk discrete element models were determined. Finally, the calibrated parameters were validated through tensile tests, uniaxial compression tests, and bending tests of cotton stalks. The simulation results show that the relative errors between the simulated and measured maximum loads for the 8.5 mm- and 10.5 mm-diameter cotton stalk models were 1.21% and 0.08%, respectively, indicating good agreement. These results verify the accuracy and reliability of the established cotton stalk discrete element models and provide data support and a theoretical basis for numerical simulation of the defibration process of cotton stalks with different diameters and for the structural optimization of cotton stalk defibration devices.

The objective of this research was to characterize the cotton stalk resource. This paper also focused on the manufacturing of formaldehyde-free particleboards using whole cotton stalk. The effects of opening particle sizes and cotton ball residue ratios on performance properties of manufactured particleboard was assessed. Modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), and thickness swelling (TS) were characterized. Particleboards manufactured from four different opening particle sizes (6, 8, 10, and 20 mm) using an emulsifiable polymeric isocyanate adhesive (eMDI) were investigated. Similarly, the same performance properties were evaluated using four different cotton ball residue ratios (0, 5, 10, and 15 wt%). Results showed that the stem length and diameter of cotton stalks cultivated in Queensland (Australia) vary greatly and range from 160 to 890 mm and 5.03 to 10.88 mm, respectively. The highest weight proportion of the resource is the cotton stem making up 46 wt% of the available resource. The highest average values of MOR, MOE, IB, and the lowest TS were observed for boards with an opening particle size of 8 mm. The cotton ball residues had detrimental effects on the mechanical properties with a decrease in properties observed with increasing cotton ball residue load.