Numerical investigation of locomotion characteristics of two tracked vehicle chassis configurations on deep-sea sediments

Despite the widespread use of inverted-trapezoidal and semi-circular rectangular tracked vehicles in deep-sea engineering, the mechanisms governing their locomotion differences on soft seabed sediments remain unclear. This study establishes an MBD–DEM coupled framework with multi-objective calibration against pressure–sinkage, direct-shear, and track plate–sediment shear responses, and systematically compares the two chassis configurations. The relative performance of the two configurations varies across operating conditions and response metrics. The ITTV generally sustains higher steady state traction, whereas the SCRTV exhibits lower sinkage and smaller pitch responses. Under the intermediate mass condition, increasing travelling speed narrows the difference in steady state traction but causes the slip ratio crossover to occur earlier, after which the ITTV maintains a lower slip ratio. Under the highest investigated mass condition, however, the SCRTV exhibits greater transient stability during motion initiation. Mechanistically, different longitudinal grounding profiles redistribute track–sediment contact pressure and particle force transmission, altering sediment mobilization and thereby governing traction, sinkage, and slip. On sloping terrain, the SCRTV exhibits greater directional stability, whereas the ITTV maintains more persistent track–ground contact on dual-peak terrain and shows greater terrain adaptability. These findings provide a mechanistic basis for chassis optimization of deep-sea tracked mining vehicles.