Sinkage Characteristics Research Articles

Evaluation of Ground Pressure, Bearing Capacity, and Sinkage in Rigid-Flexible Tracked Vehicles on Characterized Terrain in Laboratory Conditions.

Trafficability gives tracked vehicles adaptability, stability, and propulsion for various purposes, including deep-sea research in rough terrain. Terrain characteristics affect tracked vehicle mobility. This paper investigates the soil mechanical interaction dynamics between rubber-tracked vehicles and sedimental soils through controlled laboratory-simulated experiments. Focusing on Bentonite and Diatom sedimental soils, which possess distinct shear properties from typical land soils, the study employs innovative user-written subroutines to characterize mechanical models linked to the RecurDyn simulation environment. The experiment is centered around a dual-tracked crawler, which in itself represents a fully independent vehicle. A new three-dimensional multi-body dynamic simulation model of the tracked vehicle is developed, integrating the moist terrain's mechanical model. Simulations assess the vehicle's trafficability and performance, revealing optimal slip ratios for maximum traction force. Additionally, a mathematical model evaluates the vehicle's tractive trafficability based on slip ratio and primary design parameters. The study offers valuable insights and a practical simulation modeling approach for assessing trafficability, predicting locomotion, optimizing design, and controlling the motion of tracked vehicles across diverse moist terrain conditions. The focus is on the critical factors influencing the mobility of tracked vehicles, precisely the sinkage speed and its relationship with pressure. The study introduces a rubber-tracked vehicle, pressure, and moisture sensors to monitor pressure sinkage and moisture, evaluating cohesive soils (Bentonite/Diatom) in combination with sand and gravel mixtures. Findings reveal that higher moisture content in Bentonite correlates with increased track slippage and sinkage, contrasting with Diatom's notable compaction and sinkage characteristics. This research enhances precision in terrain assessment, improves tracked vehicle design, and advances terrain mechanics comprehension for off-road exploration, offering valuable insights for vehicle design practices and exploration endeavors.

Study on the Pressure–Sinkage Process and Constitutive Model of Deep-Sea Sediment

The driving performance of subsea mining vehicles is greatly affected by the pressure–sinkage characteristics of deep-sea sediment. Therefore, it is of great importance to analyze the microscopic properties of deep-sea sediment and establish the corresponding pressure–sinkage model for the safe operation of subsea mining vehicles. Hence, the present paper focuses on the physical properties of deep-sea sediment to provide a preliminary understanding of its pressure–sinkage process and evolution according to the solid–liquid two-phase flow characteristics and particle flow mechanism. In addition, the stress loading time and the rheological theory are applied in order to introduce a four-element model that describes the various pressure–sinkage stages that correspond to each stage of deep-sea sediment evolution. On this basis, the parameters of the pressure–sinkage constitutive model are determined by a specific calculation method. Moreover, a new pressure–sinkage constitutive model of deep-sea sediment that considers the time-variable mechanical properties is established in order to describe the full sinkage process. Finally, research results from the existing literature and experimental data are used to verify the rationality and correctness of the model. The results show that the proposed pressure–sinkage constitutive model is in good agreement with experimental data and is effective in describing the evolution of the mechanical properties and the trend in the sinkage rate of deep-sea sediment at various stages. A comparison with the Kelvin model indicates that the proposed pressure–sinkage constitutive model provides superior accuracy with the use of fewer parameters. Consequently, this study can provide a theoretical basis and technical support for the design of subsea mining vehicles.

Research on repeated loading and sinkage characteristics of soil by numerical analysis

The research on repeated loading and sinkage characteristics of soil can calculate the sinkage of wheel and track in driving process more precisely, so it can help calculate the vibration characteristics and driving resistance of vehicle more accurately. This paper analysis the soil repeated loading and sinkage characteristics based on finite element method. The results shows that the unloading and reloading process of soil can be assumed as a straight line with slope of k on load-sinkage curve, here k is called rebound coefficient. The research conclusion can provide reference to the vehicle terramachanics and other research involved soil deformation.

The sinkage characteristics and prediction of a planetary rover based on a similarity model experiment

The environment on an extraterrestrial planet is complex, with soft surfaces and low gravity, which make it easy for rovers to sink and skid. Excessive sinkage may occur under large slip conditions of probe rovers and could influence the survey mission. Predicting the sinkage performance of wheels under slip conditions is important for the development and performance evaluation of exploration rovers. This paper presents a dimensional analysis on the main parameters of the wheel–soil interaction system; the analysis was performed based on the similarity law, for which corresponding similar scale values were obtained. Referring to the lunar surface gravity environment, we have produced a 1/2 scaling model rover. To investigate the sinkage characteristics of the model rover, tests were performed with different wheel loads (5 N, 7 N, and 9 N) and soil states (loose, natural, and compact). The characteristic parameters of a rear wheel rut were also analyzed, including rut depth (hereinafter referred to as apparent sinkage) and slip ratio (hereinafter referred to as apparent slip ratio). Experimental results were analyzed to evaluate the sinkage characteristics and to draw conclusions. Sinkage models for the rover under different soil states were proposed, and verification and error analyses for the sinkage models were conducted using indices such as the mean relative error and root mean squared error. The experimental results and conclusions are useful for optimal rover design and improvement/verification of wheel–soil interaction mechanics models.

The sinkage characteristics and the supporting capacity of a submerged floating vehicle driving in deep soft terrains

A submerged floating vehicle, which is utilized in deep soft terrains, has a superior trafficability to those of traditional vehicles. This study focuses on understanding and improving the sinkage characteristics of a submerged floating vehicle travelling on deep soft clay. The factors which influence the sinkage characteristics were analysed, and a soil bin experimental model was established using the similarity theory. A series of experiments was designed for carrying out tests on the sinkage with respect to the pressure, the sliding speed, the aspect ratio and the moisture content of the soil. The experimental results show that the sinkage of the floating device sliding increased with increasing moisture content of the soil. They also show that the sinkage increases with increasing pressure and decreases with increasing aspect ratio of the floating device. By analysing the problems and the challenges which exist in an empirical formula or a semiempirical formula when facing the sinkage of a floating device, a support vector machine for a regression model is proposed in order to construct a multiple non-linear regressive prediction model using experimental data. Further evidence was provided to substantiate the merits of the application of the support vector regression method when dealing with the issue of predicting the sinkage.

Performance evaluation of a wire mesh wheel on deformable terrains

Because of the unique lunar environment, a suitable wheel for lunar rover decides the rover’s trafficability on deformable terrains. The wire mesh wheel (hereinafter referred to as WMW) has the advantages of light weight and superior stability, been widely adopted for lunar rovers. But a comprehensive research on performance of WMW on deformable terrains has not been conduct. This paper would provide particular study on a type WMW, including quasi-static pressure-sinkage test and driving performance. A novel pressure-sinkage model for the WMW on deformable soils was presented. In order to investigate the sinkage characteristics of the WMW, tests were performed using a single-wheel testbed for the WMW with different loads and velocities. The effects of load and velocity on sinkage were analyzed, and the relationship between real and apparent sinkage was presented. The research on traction performance of WMW under different slip ratios (0.1–0.6) was also conducted, contrast tests were proceed by using a normal cylindrical wheel (hereinafter referred to as CW). The traction performance of WMW is analyzed using performance indices including wheel sinkage, drawbar pull, driving torque, and tractive efficiency. The experimental results and conclusions are useful for optimal WMW design and improvement/verification of wheel–soil interaction mechanics model.

Predicting the pressure–sinkage characteristics of two forest sites in Ireland using in situ soil mechanical properties

The mechanical properties of two forest soils in Ireland were determined in order to model the pressure−sinkage characteristics of the forest floor. The stiffness values of the surface mat and the underlying weak peat substrata, and Young's modulus were determined from in situ load–sinkage experimental data obtained from the sites. The measured mean values of stiffness of surface mat (underlying peat soil) were found to vary between 368 and 1634 (1028 and 4320 kN/m 3 ). The measured mean value of Young's modulus of the forest floor was found to vary between 427 and 718 kN/m 2 . A non–linear model that predicted the pressure–sinkage characteristics of the forest floor, with less than 19% error, was developed. Application of the non-linear model for prediction of potential site damage by timber harvesting and extraction machinery traffic was exemplified. Such application of the model has an advantage in that it only requires Young's modulus of the soil and harvesting machine configuration to be known.

SW—Soil and Water: In situ Determination of Engineering Properties of Soil

A response surface methodology which employs an orthogonal regression technique and a third-order correction was used to determine in situ engineering properties of an untilled and a tilled Yolo loam soil. The technique employed an elasto-plastic constitutive material model for soil with Drucker Prager yield criterion. The plate sinkage test results using a 101·6 mm circular plate were used to estimate five engineering properties of soil (logarithmic unloading and reloading bulk modulus κ; Poisson's ratio ν; yield surface shape factor K; cohesionc ; and soil internal friction angle φ). Although the parameters estimated from 101·6 mm plate tests could predict the sinkage of this plate accurately, use of these values underpredicted the sinkage characteristics of a 50·8 mm diameter plate, perhaps due to the edge effect. These results indicate the need for interface elements to properly model the edge effects that occur in plate sinkage tests. Alternatively, the use of large-diameter plates may reduce the edge effects.

Sinkage characteristics of workpieces in flexible particulate bed fixtures: An experimental and numerical investigation : Jeries Abou-Hanna, Kiyohisa Okamura, and Timothy McGreevy, pp. 359–369

Sinkage characteristics of workpieces in flexible particulate bed fixtures: An experimental and numerical investigation : Jeries Abou-Hanna, Kiyohisa Okamura, and Timothy McGreevy, pp. 359–369

Sinkage characteristics of workpieces in flexible particulate bed fixtures: An experimental and numerical investigation

The concept of flexible particulate bed fixtures (FPBFs or PBFs) in low-volume manufacturing environments has been investigated for its potential use in manufacturing environments. This paper reports findings regarding one of several performance issues that have been under investigation in the past five years, namely the displacement (sinkage) of the workpiece during the compaction process of the particulate. A bed fixture prototype was instrumented to detect the sinkage of a slender cylindrical workpiece and of the compacting plate during compaction. In addition, sinkage characteristics of finned rod workpieces as a function of fin size, rod size, and fin location were investigated to determine the effects that workpiece size and shape have on sinkage. A finite element model of the bed was also used to perform numerical tests and to study the effects of submergence depth and angular position of plain slender rod and finned rod workpieces on sinkage. Sinkage is dependent on submergence depth and workpiece initial orientation. Furthermore, fin size and location have a significant effect on the sinkage of the rod with respect to the compacting surface. These results provide trends helpful in applying the particulate bed fixture methodology to environments requiring tight indexing tolerances, such as machining or surface inspection.