Figure - uploaded by Feng Xu
Content may be subject to copyright.
Source publication
Based on main physical and mechanical properties of deep-sea sediment from C-C poly-metallic nodule mining area in the Pacific Ocean, the best sediment simulant was successfully prepared by mixing bentonite with a certain content of water. Compression–shear coupling rheological constitutive model of the sediment simulant was established by endochro...
Context in source publication
Context 1
... bentonite has similar mineral components to the deep-sea sediment (with large content of montmorillonit), it can be used to prepare sediment simulant by mixing with a certain content of water in order to have the same shear strength as the deep-sea sediment [8]. Table 3 lists the main physical and mechanical parameters of the best sediment simulant as well as the deep-sea sediment for comparison. ...Citations
... The compressive force as well as the shear force play a role in this phenomenon. Xu et al. [62] deduced a rheological model that combined compression and shear, utilizing the internal time theory. Its parameters were obtained through compressionshear-coupled experiments, and the measurement of its creep curve was conducted using a custom-built creep meter that combined compression and shear, which was verified by making simulated soil. ...
... The compressive force as well as the shear force play a role in this phenomenon. Xu et al. [62] deduced a rheological model that combined compression and shear, utilizing the internal time theory. Its parameters were obtained through compression-shear-coupled experiments, and the measurement of its creep curve was conducted using a custom-built creep meter that combined compression and shear, which was verified by making simulated soil. ...
In response to the anticipated scarcity of terrestrial land resources in the coming years, the acquisition of marine mineral resources is imperative. This paper mainly summarizes the development of underwater collection and transportation equipment of polymetallic nodules in deep-sea mining. Firstly, the collection equipment is reviewed. The deep-sea mining vehicle (DSMV), as the key equipment of the collection equipment, mainly includes the collecting device and the walking device. The micro and macro properties of sediments have a great influence on the collection efficiency of mining vehicles. For the collecting device, the optimization of the jet head structure and the solid–liquid two-phase flow transport of the hose are discussed. The structure of the walking device restricts mining efficiency. The optimization of the geometric structure is studied, and the geometric passability and lightweight design of the walking device are discussed. Secondly, the core of transportation equipment is the lifting device composed of a riser and lifting pump. In order to explore the key factors affecting mineral transport, the lifting device is summarized, and the design optimization of the lifting pump and the factors affecting the stability of the riser are discussed. Then, the relationship between each device is discussed, and the overall coupling of the device is summarized. Finally, the existing problems and future research focus are summarized.
... Relevant studies showed that the traction force generated by a track is through the process of terrain/soil shearing, and the tractive performance of the track-laying-vehicles is determined by the interaction between the track and the soil, which strongly depends on the structure of the track, such as the track of shoes and belt, and the soil of moisture content (Gill & Vanden Berg, 1967;Yokoyama et al., 2020). As an essential issue in the terramechanics, the prediction of tractive performance is extensively concerned by researchers (Battiatoetal & Diserens, 2017;Feng et al., 2018;ten Damme et al., 2021;Xu et al., 2022;Sandu et al., 2019). Furthermore, forces generated on different horizontal surfaces in a grouser shoesoil interaction system are always considered a piece of significant information for promoting tractive performance through the method of parameter optimization (Ani et al., 2018;Edwin et al., 2018;Shin et al., 2020;Zhou et al., 2021). ...
This study aims to investigate the influence of moisture contents and grouser heights on traction force exerted on different surfaces in the track-soil interaction system. A sandy loam was employed for acquiring the soil parameters, such as kc, kφ, n, C, Ca, δ, φ, and γ. These parameters were obtained through the mean of the bevameter technique. Moisture contents of the sandy loam were changed from low to high levels, which could be listed as 1.4%, 8.0%, 14.7%, and 22.2% at last. The direct shear and penetration tests were performed for each soil condition of the moisture content, respectively. The model of the single-grouser-shoe (track model) had a length of 9 cm, a width of 15 cm, and varied grouser heights from 0 to 15 cm with a 0.5 cm interval. Based on the calculation result, in general, the shearing force produced by the bottom surface always performs better than either the shear force on the grouser-tip surface or two lateral surfaces. Simultaneously, prediction results also show that the shearing forces were significantly influenced by the level of moisture content in the soil.
sandy loam; single-grouser-shoe; moisture contents; shearing force
... Zhu et al. [20] established a thermo-hydro-mechanical dynamic response model of saturated porous deep-sea sediments under vibration of mining vehicles, based on Green-Lindsay (G-L) generalized thermoelasticity theory and Darcy's law. Xu et al. [21] established a compression-shear coupled rheological constitutive model of sediment simulants using internal time theory, and deduced a new formula for calculating the steering traction force of tracked mining vehicles. The effects of slewing speed, track spacing and length of track and deep-sea sediment contact on slewing traction are analyzed. ...
The four-track walking mining vehicle can better cope with the complex terrain of cobalt-rich crusts on the seabed. To explore the influence of different parameters on the obstacle-crossing ability of mining vehicles, this paper took a certain type of mine vehicle as an example and establish a mechanical model of the mine vehicle. Through this model, the vehicle’s traction coefficient variation could be analyzed during the obstacle-crossing process. It also reflected the relationship between the obstacle-crossing ability and the required traction coefficient. Many parameters were used for this analysis including the radius of the guide wheel radius, ground clearance of the driving wheel, the dip angle of the approaching angular and the position of centroid. The result showed that the ability to cross the obstacles requires adhesion coefficient as support. When the ratio between obstacle height and ground clearance of the guide wheel was greater than 0.7, the required adhesion coefficient increased sharply. The ability to cross obstacles will decrease, if the radius of the guide wheel increases, the height of the driving wheel increases or the dip angle of the approaching angular increases. It was most beneficial to cross the obstacle when the ratio of the distance between the center of mass and the front driving wheel to the wheelbase is between 0.45‒0.48. The results of this paper could provide reference for structural parameter design and performance research for mining vehicles.
... In existing studies, the existing empirical model, combined with the simulated sediment material in the laboratory, is typically used for motion analysis of the crawling robots. Xu et al. [8] prepared an optimum sediment simulant based on the main physical and mechanical properties of sediments in the Pacific Ocean, and combined their theory with endochronic theory to analyse the effects of the turning velocity, crawler spacing, and contact length with sediment on movement characteristics. However, the unavoidable effects of hydrodynamic and current interference were neglected in the process of establishing the motion model. ...
Due to the nonlinearity of the deep-seafloor and complexity of the hydrodynamic force of novel structure platforms, realising an accurate motion mechanism modelling of a deep-sea landing vehicle (DSLV) is difficult. The support vector regression (SVR) model optimised through particle swarm optimisation (PSO) was used to complete the black-box motion modelling and vehicle prediction. In this study, first, the prototype and system composition of the DSLV were proposed, and subsequently, the high-dimensional nonlinear mapping relationship between the motion state and the driving forces was constructed using the SVR of radial basis function. The high-precision model parameter combination was obtained using PSO, and, subsequently, the black-box modelling and prediction of the vehicle were realised. Finally, the effectiveness of the method was verified through multi-body dynamics simulation and scaled test prototype data. The experimental results confirmed that the proposed PSO–SVR model could establish an accurate motion model of the vehicle, and provided a high-precision motion state prediction. Furthermore, with less calculation, the proposed method can reliably apply the model prediction results to the intelligent behaviour control and planning of the vehicle, accelerate the development progress of the prototype, and minimise the economic cost of the research and development process.
... Wu et al. [16] established a traction force model of a tracked miner on the deep-sea soft sediment by studying the cohesive action between a grouser and the sediment, which revealed the influence of parameters of the sediment and sizes of the tracked miner structure on the traction force. Wang et al. [17] tested the applicability of two kinds of empirical models of shear stress-displacement to the deep seabed and promoted a new empirical model for saturated and plastic soil; Xu et al. [18] initially employed a compression-shear coupling rheological model into the analyses of the sinkage and thrusting force of a tracked miner and deduced a new turning traction force. Li et al. [19] obtains a relationship between the grouser height and the water jet based on elastic-plastic traction force model aiming at the cause of sticky soil shaped on the track. ...
Based on our direct shear creep experiment and the direct shear rheological constitutive model, a semi-empirical time-dependent parameter of the shear strength is obtained by Mohr–Coulomb shear strength theory, and different time-dependent traction force calculations between deep-sea sediment and a tracked miner are conducted by the work-energy principle. The time-dependent traction force calculation under its influencing factors, including the time, track shoe number, and grounding pressure, are analyzed and proved to be valid by the traction force experiment of a single-track shoe. The results show that the time-dependent cohesion force obtained by a semi-empirical way can be easily used to deduce the time-dependent traction force models under the different grounding pressure distributions and applied into deep-sea engineering application conveniently; the verified traction force models by the traction force experiment of a single-track shoe illustrate that traction force under the decrement grounding pressure distribution is the worst among the four kinds of grounding pressure distributions and suggested for evaluating the most unfavorable traction force and calculating the trafficability and stability of the deep-sea tracked miner.
... Li et al. [5] established a prototype of a seabed mining vehicle and evaluated its trafficability through dynamic simulations. A formula was derived by Xu et al. [6] for calculating the turning traction force in consideration of the pushing resistance and sinkage of the vehicle, and the effects of the turning speed, track pitch and contacting length on the turning traction force were investigated. UMARU et al. [7] developed equations and models for tracked vehicles during steering motions, and pointed out that only the hydrodynamic force and traction force would be affected by the driving speed. ...
In this paper, a nonlinear integrated multi-body dynamic (MBD) model of a deep-sea mining (DSM) system was developed. A particular nonlinear interaction model between the mining vehicle and seabed sediment was derived. The fluid resistance and resistance torque acting on the vehicle were obtained by computational fluid dynamics (CFD) numerical simulations. In addition, a rigid-flexible coupled discrete element method (DEM) was adopted to model an extremely long mining riser efficiently and accurately. Developed by C# program, a user-defined subprogram was intended to establish the DEM model of the riser. A motion control system model for trajectory tracking of the vehicle was developed in which the fuzzy control algorithm and the fuzzy adaptive PID control algorithm were used to control the speed and speed ratio of the tracks respectively. Furthermore, the collaborative simulation between the dynamic model and the control model was achieved, and a coordinated motion mode for the total mining system was proposed and simulated. Accordingly, the trajectory tracking accuracy and slip of the vehicle, the spatial state change of the riser, and the interaction forces among subsystems were analyzed. This research can provide a valuable theoretical basis and technical reference for the integrated design, performance prediction and operation control of the practical DSM system.
