Optimization of subsoiler design using similitude-based DEM simulation and soil bin testing on cohesive-frictional artificial soil

The study highlights the need for effective and efficient methods in designing tillage shanks to alleviate deep soil compaction, especially in wet soil conditions. Current techniques relying on full-scale tillage tools testing are prone to costly and time-consuming engineering product development cycles. DEM simulation of soil-to-shank interaction was utilized for screening twelve geometrically scaled (1:5.63) shanks to top-ranked six shanks, aiming reduced soil horizontal forces and maximum bulk density difference. Six scaled shanks (a straight, a bent, and four paraplow shapes) were fabricated and tested using a split-plot design soil bin experiment on cohesive-frictional artificial soil to investigate their performances on soil reaction forces and soil loosening parameters. Shank design had significant effects (p < 0.05) on energy responses (soil horizontal and vertical reaction forces), above-ground soil loosening (cross-sectional area, trench width, bulk density difference), and below-ground soil loosening (soil rupture area, D1 and D2) parameters. Using an optimization profiler, S-3 (β = 60°, α = 45°) demonstrated the best overall desirability score (0.58) with objectives reducing soil reaction forces and maximizing soil loosening. Manufacturing the S-3 to a full scale is proposed for evaluating its efficiency in tillage energy and soil loosening on field soil conditions for subsoil compaction management.