Xiaonan Li

Soil tillage is energy-intensive, and the cutting resistance of soil-engaging tools is its largest single loss. Ultrasonic vibration-assisted cutting (UVAC) can reduce this resistance, but quantitative studies have concentrated on longitudinal vibration; transverse vibration, which loads the soil by cyclic lateral squeeze and release, remains largely unexplored. A calibrated discrete element model of a transverse UVAC tool–soil system is developed to determine how amplitude, frequency and cutting speed govern drag reduction and to identify the contact-level origin of the effect. Bench tests at 20 kHz supplement the simulated design space with an additional operating condition and confirm the predicted forces at eight settings—five vibration conditions and three baselines—with a mean relative error of 8.7% and the baselines within 6%; one calibrated parameter set is used throughout. Over 30–70 µm, 25–45 kHz and 0.03–0.07 m s⁻¹, amplitude dominates, raising the drag reduction from 44.10% to 68.18%, whereas frequency acts mainly through its quadratic term and its interaction with amplitude, and cutting speed enters the same coupling. Box–Behnken optimization places the optimum at 70 µm, 25 kHz and 0.07 m s⁻¹, with a DEM-verified reduction of 69.25% against a predicted 69.53%. Contact analysis shows that the vibration shifts load from normal compression to tangential shear and converts bond failure from concentrated rupture into progressive degradation. Amplitude is therefore the primary design variable for transverse UVAC in sandy loam at 9% moisture, with frequency and speed modulating its expression.

To address unstable seed filling and susceptibility to seed damage in air-suction peanut seed-metering devices, a flexible cell-hole seed-metering device comprising a double-layer seed-metering disc, elastic rubber cell-hole inserts, and conical springs was developed. EDEM simulations, bench tests, and field tests were conducted to investigate the effects of cell-hole type, cell-hole height, and seed-metering disc speed. Seed velocity, force, and disturbance transmission characteristics were analyzed in the simulations, while seed-metering performance was evaluated using the miss-seeding, multiple-seeding, and seed-damage indices in the bench tests. The results showed that the single ellipsoid cell-hole type produced greater consistency between the directions of seed motion and cell-hole movement. A cell-hole height of 5 mm provided an effective balance between seed disturbance and damage reduction, while a seed-metering disc speed of 20 r/min improved seed-adsorption stability. In the field tests, the mean miss-seeding, multiple-seeding, and seed-damage indices were 3.75%, 4.54%, and 1.75%, respectively. These findings demonstrate that flexible cell holes can guide seeds to move with the cell holes and promote the stable transmission of localized disturbance throughout the seed mass, thereby providing an effective approach to improving seed-adsorption stability while limiting mechanical damage.

During ultrasonic detection of buried seeds after sowing, variations in soil conditions can strongly affect ultrasonic signals and make seed identification difficult. In this study, soil moisture content, particle size, and compaction pressure were investigated to evaluate their effects on ultrasonic frequency-domain responses and seed-presence discrimination. The first-wave dominant frequency (F_g) and dominant-frequency amplitude ratio (k) were extracted from the received signals. Seed presence altered the spectral peak position and amplitude distribution, whereas the direction of the F_g shift varied with soil conditions, limiting its use as a standalone discrimination feature. In sieved soil, k showed the best discrimination at 10% moisture content, with an AUC of 0.951. Using the predefined threshold k = 1, the sensitivity, specificity, and overall accuracy were 94.7%, 81.3%, and 88.0%, respectively. In non-sieved field soil, the highest AUC was 0.923 at 15% moisture content, with an accuracy of 90.0% using k = 1. An additional 40 independent tests conducted at 15% moisture content and 0.50 MPa yielded a sensitivity of 95.0%, a specificity of 90.0%, and an overall accuracy of 92.5%. These results demonstrate the potential of ultrasonic frequency-domain features for identifying buried seeds under controlled soil conditions.