Load Movement Research Articles

Bidirectional static loading tests on barrette piles. A case history from Ho Chi Minh City, Vietnam

Bidirectional static loading tests were conducted on two strain-gage instrumented barrettes installed to 72 m depth in Ho Chi Minh City, Vietnam. The barrettes were to support a 16-storey building with 5 basements. The soil profile comprised layers of medium coarse to fine sand, medium clay, firm to stiff clayey soil, and dense sandy silt. The region is experiencing an ongoing land subsidence affecting the upper about 40 m of soil and, on average in the city, the ground surface is currently settling 16 mm/year. The test records were processed by means of effective stress analysis to provide the axial pile force distribution, load transfer functions, and equivalent head-down load–movement curve. The analysis was then used to obtain the equivalent pile-head load–movement response adjusted to the planned 22 m deep basement excavation. Load transfer functions were back-calculated from the test records and indicate that the construction will show somewhat large load-transfer movement. However, because the equilibrium plane will be below the subsiding layers, below 40 m depth, downdrag is not expected to affect the building. The load response of the barrettes is compared to the results of a bidirectional (BD) loading test on a 1.8 m diameter bored pile at an adjacent project.

A Fast Front-End Monitoring Method for Mutual Inductance and Load Movement in SS-Compensated Wireless Power Transfer Systems Based on Harmonics Extraction

A Fast Front-End Monitoring Method for Mutual Inductance and Load Movement in SS-Compensated Wireless Power Transfer Systems Based on Harmonics Extraction

Load-balancing routing algorithms for service congestion avoidance in LEO optical satellite networks

The low-Earth-orbit optical satellite network (LOSN) is an attractive solution to realize the end-to-end service quality of large-scale services, and it is the basis of establishing the 6G mobile network with high throughput and high reliability. However, the current LOSN is practically unable to achieve such high throughput for global service access. First, the centralized deployment of ground gateways will cause a heavy traffic load in the space segment of the LOSN, which becomes the bottleneck constraining the further growth of network throughput. Second, the high-speed movement of LEO satellites will cause continuous movement of traffic load, which will affect the scalability of routing computing. In this paper, two routing algorithms are proposed to increase the throughput in the dynamic LOSN topology. The congestion-aware load balancing (CALB) algorithm is proposed to address the inter-satellite link congestion in the dynamic LOSN topology. Then, a load-balancing routing algorithm based on satellite–ground cooperation (SGC-LB) is proposed to further reduce the impact of the network bottleneck. To evaluate the performance of the proposed routing algorithm, extensive simulations were performed on a 288-satellite Walker-Star constellation with inter-satellite links. The service blockage rate and network bandwidth utilization rate are evaluated showing the effectiveness of the proposed routing algorithm. The network using the SGC-LB algorithm can accommodate 60.00%, 56.00%, 42.22%, and 33.33% more services than using the Shortest Path algorithm, Sway algorithm, CALB algorithm, and Anycast algorithm, respectively, with zero service congestion during the simulation. The SGC-LB also gains a 6.04%, 5.00%, 5.04%, and 0.77% higher network utilization rate than the Shortest Path, Sway, CALB, and Anycast algorithms, respectively.

Дослідження нелінійних горизонтальних коливань слабозакріпленого вантажу при русі автомобіля

The improvement of the methods of reducing dynamic loads in the elements of self-propelled transport machines and transported goods is based on the results of the analysis of dynamic phenomena that occur during their operation, which is due to the growth of load, increase of working speeds, combination of loading and unloading operations with other technological operations, increase in productivity.
 To prevent damage and ensure traffic safety, packaging and artificial cargoes are secured in car bodies, train carriages and ship holds with wire ties, thrust and spacer bars, tying and other methods.
 But during transportation, as a result of stretching and breaking of stretch marks and pulling out of nails, goods are damaged, moving in a body, wagon or hold. Therefore, it is very important at the design stage of the fastening structure to establish the possible movement of the load, as well as to ensure it within the given limits in order to prevent damage to the load.
 The authors proposed a method of calculating load fluctuations in the body of a truck using the example of two loads of different weights. A kinematic diagram of a self-propelled transport machine with sequential elastic coupling of transported loads was built and a study of nonlinear horizontal oscillations of a loosely secured load during the movement of the vehicle was carried out.
 According to the results of the research, graphs of the dependences of the dimensionless amplitude of the weight of the load relative to other loads depending on the gap between the fasteners were constructed. Maps of regions of stable movements are constructed and the region of unstable movements of loads is shown. It is noted that although such an area of unstable movements is quite small, but under certain conditions of movement of the vehicle and weakly secured cargo, phenomena can occur that can cause a traffic accident.

Numerical Appraisal of Reinforced Concrete Dapped-End Girder Under High-Fatigue Fixed Pulsating and Moving Loads

This paper presents the numerical evaluation of structural response and fatigue life of a Reinforced Concrete Dapped-End Girder (RCDEB) and associated fatigue life under fixed pulsating and moving loads. For that, a finite element (FE) model of RCDEB is developed using a three-dimensional FE analysis code, Concrete Model of 3-Dimensions (COM3D), and analyzes the FE model under high-fatigue loads by adopting a certain percentage of verified maximum static capacity of the girder. The COM3D system is activated with a multidirectional active crack approach which considers the space averaging of stress–strain in an element. The experimental validation of the numerical analysis is also performed in the laboratory using a small-scale model of the RCDEB under the fixed pulsating load. The experimental validation demonstrates good agreement with the FE analysis. However, the moving load is not considered in the experimental scheme because of the limitation in the testing facility. Finally, it is found from the FE analysis that the moving load, as compared with the fixed pulsating load, has the greatest effect on fatigue performance of the girder, causing about a three-order reduction in fatigue life at the same percentage static capacity of the girder. An increase in the fatigue life of approximately one order is also recorded in the analysis under the static midpoint load of 350 kN as compared with the moving load. Moreover, it is also observed that the reentrant corner of the RCDEB is more vulnerable to fatigue, implying that the hanger bars close to this corner resisted the stresses after the concrete cracked. As a result, strengthening the reentrant zone is recommended.

Sediment sink-source transitions in the middle and lower reaches of the Yangtze River estuary

Human activities have severely altered the Yangtze River (Changjiang) Estuary’s pattern, beach-trough shape, and delta in recent decades. Existing research has studied the sediment “source–sink” relationship between the Yangtze River mainstream and estuary using gauged suspended sediment data. This method overestimated the decline in the suspended sediment concentration in the estuary, as riverbed scouring or deposition have not filtered out amounts related to sand mining or waterway dredging. This study took the Yangtze River Basin as the research subject and used spot observed runoff, sediment, and riverbed topography data gathered between 1980 and 2020 to analyze the sediment trapping effect of the Three Gorges Reservoir (TGR) and study the “source-sink” relationship of suspended sediment transport in the middle-lower reaches of the Yangtze River. The Yangtze Estuary Delta is dominated by scouring, which shows an increasing trend. During the operation of the TGR (2003–2020), the suspended sediment load entering the Yangtze Estuary from the Yangtze River mainstream decreased by 68% compared to the amount prior to operation commencing (1960–2002). However, studies have found that there are still large amounts of bottom sand with riverbed load movement characteristics after the operation of the Three Gorges Project and that riverbed souring of the downstream dam has increased the degree of deposition recharge. The amount of sediment in the Yangtze Estuary decreased between 2003 and 2018 compared with the period 1981 to 2002, with an annual decrease of 16.9%. The cumulative deposition of the Yichang–Datong and Datong–Xuliujing reaches from 1981–2002 was 3.13×108 m3 and 1.60×108 m3, respectively, and cumulative scouring from 2002–2018 was 28.52×108 m3 and 16.01×108 m3. This study concluded that even if the suspended sediment load entering the estuary decreased significantly after the operation of the TGR, the riverbed in the middle-lower reaches of the Yangtze River has gradually transformed from the “sink” of sediment deposition to the “source” of sediment supply.

Building a model of the impact grinding mechanism in a tumbling mill based on data visualization

A mathematical model was built based on data visualization for the impact grinding mechanism in a tumbling mill, which is mainly implemented during coarse grinding. The determination of impulse interaction parameters is problematic due to the difficulty of modeling and the complexity of hardware analysis of the behavior of intramill loading. Conceptually, it was envisaged to identify the relative dynamic parameters of the impact action as components of the model, which are criteria for the similarity of the loading movement and the grinding process. Impact power was taken as an analog of grinding performance. The initial characteristic of the impact was considered to be the averaged vertical component of the speed of loading movement in the flight zone at the boundary of contact with the shear layer. The formalization of the model revealed the effect on the performance of the mass fraction of the flight zone and the reversibility of loading. The method of numerical modeling was applied, based on experimental visualization of the behavior of granular loading in the cross section of a rotating chamber. The influence of the rotation speed on the performance at a chamber filling degree of 0.45 and a relative particle size of a milling load of 0.0104 was estimated by experimental simulation. The maximum productivity value was found at the relative speed of rotation ψω=1–1.05. A rational condition for impact grinding at ψω=0.75–0.9 has been established. The test proved the effectiveness of using visualization to evaluate dynamic loading interaction analogs. Verification of modeling results was implemented by comparison with the data of the technical standard. The use of similarity criteria unifies approaches to modeling different mechanisms of destruction. The model built makes it possible to predict the rational parameters of the grinding processes by impact, crushing, and abrasion

Total hip arthroplasty monobloc stem neck rupture in patient with massive heterotopic ossifications: a case report and literature review.

Fractures of the femoral stem neck are a rare complication in hip prosthetic surgery, especially in non-modular components. The authors report a case associated with massive heterotopic ossifications, with the purpose to analyze risk factors and specific characteristics. A case of femoral monobloc stem neck rupture is described. A non-systematic literature review regarding risk factors for femoral stem neck fracture was conducted in the PubMed database. We report the case of a 61-year-old male who underwent surgery to remove calcifications four years after THA. Four months later the patient reported acute pain in the left hip, arising after a combined movement of external rotation and axial load while standing on the left foot, in the absence of any prodromic symptom. On radiographs, a displaced fracture of the neck of the hip prosthesis was revealed, together with massive heterotopic ossifications. After THA revision the patient's symptoms were resolved. Prosthetic femoral neck fractures are a rare complication. We suggest that this case represents a unique type of fatigue rupture, where neck length and the presence of massive heterotopic calcifications contributed to flexion forces, resulting in failure in the midpoint of the neck.

Investigating Fractional Damping Effect on Euler–Bernoulli Beam Subjected to a Moving Load

In this work, the dynamic response of Euler–Bernoulli beams of four different boundary conditions with fractional order internal damping under a traversing moving load is investigated. The load is assumed to be moving with different values of constant velocity. A proposed approach to obtain the closed-form solution of the problem based on Green’s functions combined with a decomposition technique in the Laplace transform domain is introduced. Several cases are studied and compared to the literature; for instance, if simply supported beam is considered, the following three cases are to be explored: the case of elastic (or undamped) beam, the damped (or viscously damped) beam, and finally the fractionally damped beam modeled by the fractional Kelvin–Voigt model. The effects to the beam dynamic response induced by magnitude of moving load velocity, damping ratio, and fractional damping order are explored. The results expressed sufficient agreement with similar problems found in literature and evidenced that the dynamic response of beams is significantly affected by varying the fractional order of beam damping as well as the moving load velocity. Accordingly, using fractionally damped materials exhibits better realistic behavior of beams and intermediate between elastic and viscous beam behaviors.

Predicting trajectory of crane-lifted load using LSTM network: A comparative study of simulated and real-world scenarios

The use of robotics automation in on-site construction is crucial for achieving precise engineering and quality output. However, there is a lack of modern literature reviews on using robotic arms as small-scale model rotary cranes for predicting suspended load trajectories. This paper presents the first comprehensive attempt to use Long Short Term Memory (LSTM), a deep learning architecture, to approximate load trajectories using a dataset collected through simulation and real-world conditions. The presented framework establishes reasonably high correlations between crane motion and load movement, indicating its effectiveness and robustness. Unlike previous works, this study uses two approaches to collect the dataset: simulation and real-world conditions. For the real-world scenario, a time-based robotic crane controller is equipped with an IMU tracking camera to record on-the-fly movement of the hanging load. For simulation data, the Unity3D platform is used to mimic a virtual environment scenario and perform effortless data generation. The proposed framework’s novelty is demonstrated by an impressive RMSE of 8.11 and graphical visualizations that provide further insights into the analyses and evaluations conducted. Overall, this study is essential for incentivizing future research in relevant on-site construction applications to enhance productivity and promote worker safety.

Dynamic Analysis of Railway Track Response Subjected to Train Moving Loads Using Finite Element Simulation

Dynamic Analysis of Railway Track Response Subjected to Train Moving Loads Using Finite Element Simulation

Method for Solving the Problem of Load Movement over the Ice Cover of a Reservoir along a Complex Trajectory

Introduction. The development of the polar regions of the World Ocean contributed to an increased interest in studying wave processes in water bodies with ice cover caused by the action of a mobile load. In most papers of domestic and foreign scientists, the ice sheet was considered as an elastic or viscoelastic plate loaded with a rectilinearly moving vertical force. However, when modeling the impact of vehicles on the ice cover, it is of interest to investigate problems in which the force moves along a more complex trajectory. Therefore, this study aims at developing a method for studying the behavior of the ice cover under the action of a force moving along a trajectory of a complex shape, obeying an arbitrary law of motion.Materials and Methods. A method for solving problems of the action of an arbitrarily moving force on the ice cover of a reservoir of finite depth filled with an inviscid incompressible fluid is proposed. The ice cover was considered as a viscoelastic plate lying on the surface of a liquid in a state of potential flow. A concentrated force moving along an arbitrary closed trajectory and being periodic in time was applied to the upper surface of the plate. Hydrodynamic pressure acted on the lower surface of the plate from the liquid side. Due to the periodicity of the load applied to the plate, an integral time transformation was used to solve differential equations describing the behavior of this system. Further, using traditional methods, formulas were obtained for calculating stresses and displacements in the plate and components of the velocity vector of liquid particles. These formulas were presented in the form of an iterated integral. Numerical methods were used to calculate integrals.Results. Calculations showed that the deflection of the ice cover increased markedly with the growth of speed and tangential acceleration of the load movement. An increase in the relaxation time of ice and a decrease in the radius of the trajectory of the load also caused an increase in deflection. The distribution of the fluid particle velocity vector over the depth of the reservoir was calculated.Discussion and Conclusions. The proposed method has shown its efficiency in solving problems about the impact of a moving load on the ice cover of a reservoir. With its help, the influence of the curvature of the trajectory of motion and the mechanical properties of ice, the kinematic characteristics of the movement of the load on the deflection of the ice cover was investigated. The method simulates the impact of vehicles on the ice cover of a reservoir. The results of its application can be used under the construction of ice roads or airdromes on ice.

Эффективное распределение тяговых сил между роботами при групповой транспортировке груза

The task of collective movement of load by wheeled robots has kinematic redundancy of drives. It allows distributing traction forces without changing the trajectory and velocity of the system. In this way, it is possible to define additional traffic quality criteria which the traction control system should strive to achieve. In addition, efficient distribution will allow the robots to move without wheel slip at a higher speed than classical control methods. Robots and cargo combined into one system mechanically and informationally, form a variable configuration transport cell (VCTC). The following transportation quality criteria are considered: no wheel slippage, maintaining a given speed, no soft bumps, minimizing work in the generator mode, maintaining the desired final charge levels of the robot batteries after transportation. The proposed methods for the efficient distribution of traction forces are based on the finding local minimum and on the Hebbian learning principle. Tests are carried out in the Simulink using the dynamic mathematical model of the VCTC. In the case under consideration, new distribution methods made it possible to increase the maximum allowable turn entry speed by 27% compared with classical control approaches. At a lower speed new method of distribution showed good results on additional transportation quality criteria. The presented material can also be used for multi-wheeled robots with steerable drive wheels.

Прямые методы моделирования движения автотранспорта в окрестности подкрепленного склона

The dynamic impact of moving vehicles can cause effects leading to landslide processes in slopes. Even insignificant displacements and speeds lead to a relative displacement of the layers. In this case, the physical and mechanical parameters of the soils that make up the slope can change significantly. For example, the decrease in adhesion C may be analogous to the decrease in the force of static friction by the transition to sliding friction. This is due to the fact that the mutual movement leads to slippage of small soil fragments relative to each other. The influence of vehicles on possible landslide processes increases with an obvious tendency to increase the speed and mass of the rolling stock. This, as well as the complex geological structure of the slopes and the need to take into account the reinforcing structures, leads to the need to build refined mechanical and mathematical models for the joint operation of road structures, the slope and the reinforcing structures in a dynamic formulation.
 The creation of a refined model of the slope geometry, the highway and the slope reinforcement structures are today solved mainly by the finite element method (FEM). The problem of constructing a numerical solution of such problems based on direct methods of integrating the equations of motion is topical. In this case, it is necessary to take into account the change in the distribution of masses when moving vehicles along the road at different speeds.
 In any of works of the author [1-6], an explicit absolutely stable scheme for integrating the equations of motion of the FEM was used to solve this problem.
 This article considers testing of the method by comparing numerical solutions with known ones for problems that are simpler in terms of topological structure. Namely, the comparison of the method with the solutions of the classical problem "movement of a massive load along a massive beam" was carried out. V.V. Bolotin's solution [7-9] was adopted as a "reference" one. Numerical solutions showed a high degree of convergence of results by the proposed and "reference" methods.

Dynamic Behavior of a Beam Resting on a Viscoelastic Two-Parameter Base and Carrying a Moving Load

Dynamic Behavior of a Beam Resting on a Viscoelastic Two-Parameter Base and Carrying a Moving Load

Composite Adaptive Synchronous Control of Dual-Drive Gantry Stage With Load Movement

In gantry systems, load usually moves according to different production tasks. The continuous change of the beam centroid position is a non-negligible factor for achieving high-performance synchronous control. Therefore, it cannot be simply treated as an external disturbance. In addition, advanced controller design and model parameter identification are very important for precision motion control systems. This article addresses the synchronous control of dual-drive gantry platforms with load movement to improve their steady-state and transient performance. Based on the analysis of the rigid and flexible characteristics of gantry mechanical components, a rigid-flexible coupling dynamic model is proposed, which provides a theoretical basis for the control system design. To ensure zero steady-state tracking error and parameter convergence in the presence of parameter uncertainties and unknown disturbances, a composite adaptive control method integrating excellent output tracking performance and parameter estimation is presented. Furthermore, the bridge between load movement and centroid position is established through frequency domain identification, which facilitates reasonable thrust distribution. Comparative experimental results are presented that confirm the effectiveness and advantages of the proposed synchronous control scheme.

Dynamic effects of vehicle traffic on a highway in the slope vicinity

This article develops the modeling of dynamic effects arising from vehicle traffic on a sloped road. The object of study is landslide slopes under the dynamic impact of mobile transport. The problem is solved using explicit absolutely stable direct integration schemes for the structural dynamics problem, taking into account the movement of massive loads. The paper considers various types of cars moving in a certain range of speeds. The speed of movement varied with a step of 10 km/h. The position of cars on different lanes of the road is considered. The heterogeneity of physical and mechanical parameters in the volume of the slope is specified in the parameters of the finite elements of the model (volume tetrahedra are used).This paper presents the results of vertical oscillations of points of one cross section of the slope. The results are presented in the form of graphs of oscillations of various points of the section, and graphs summarizing the results.

The Design and Construction of a Locally Sourced Electric Powered Stair Climbing Trolley

Buildings with staircases have grown significantly as a result of improvements in building or home structures, and the strain associated with carrying items cannot be ignored. High levels of strain are related to the movement of loads along staircases, particularly in high-rise buildings. In order to make it simple to transfer large goods up and down stairs, this project concentrated on designing and building an electric-powered staircase climbing trolley from locally sourced materials. Everyday needs in our society drive the necessity for such a system. This robotic trolley is also employed to reduce the strain associated with lifting while on level ground and over a staircase. Given this, the project aims to design, build, and test the functionality of an electric-powered stair climbing trolley that can transport items up and down the stairs as well as on flat surfaces and even rugged terrain. The trolley uses a triple interlink wheel configuration that makes it simple to move things. When comparing the designed and constructed motorized trolley machine established in this work to the hand trolley, whose performance efficiency ranges from 50% to 60% as explored in previous literature, the motorized trolley machine performed 87% more efficiently. Moving products up and down a staircase can potentially be solved with the help of a motorized trolley that was designed and manufactured specifically for this purpose.

НЕСТАЦІОНАРНА РЕАКЦІЯ ЦИЛІНДРИЧНОЇ ОБОЛОНКИ З ПРУЖНИМ ШАРОМ НА ДІЮ РУХОМОГО РАДІАЛЬНОГО НАВАНТАЖЕННЯ

An analysis of studies and publications on the issues of determining the stress-strain state of constituent structures has shown that the problems of choosing and modeling the operation of structures in the form of infinitely long cylindrical shells with a soft, weightless elastic layer have not received enough attention in the scientific literature today. The use of modern approaches to the construction of mathematical models and algorithms makes it possible to take into account various kinds of dynamic loads that are transferred to structural elements in the form of cylindrical shells.The aim of the article is to develop an analytical method for calculating cylindrical shells with a weightless soft elastic layer under the action of a moving radial load.Based on the principles and approaches to the analysis of non-stationary dynamic processes in complex shells, the paper presents an algorithm based on the application of the integral Fourier transform along the axial coordinate, as well as the use of the Runge-Kutta numerical method for integrating the transformed differential equations of shell motion in the image space. Cases of load movement with different speeds and uniform pressure wave movement are considered. The dependence of the radial displacements of the shell on the reaction of the elastic layer, represented by an approximate model, taking into account only the radial displacement, is determined. The cases of motion of a radial axisymmetric load both with constant and with varying speed are investigated. The distribution of shell deflections along the length is given for different moments of time during the movement of the load at a constant speed, as well as for the slow movement of the ring load.In this work, for the first time, a mathematical model of the non-stationary behavior of a shell with an outer layer under the action of a moving load is constructed. A comparative analysis of various shell models has been carried out and deformation patterns of both accelerated and slow motion have been constructed. The transient processes that occur at the moment of load application and the subsequent time intervals immediately after this moment are considered. The presented materials can be used for dynamic modeling of the operation of structures in the form of plates and shells.

MOTION LAWS DEVELOPMENT OF TROLLEY MOVEMENT AND TOWER CRANE SLEWING

The article presents an approach that allows to calculation optimal trajectory of load movement in the building yard. This trajectory provides avoiding obstacles in a way, that ensures the smoothness of the load movement. The essence of the developed approach is in multiple recalculations of the trajectory: the first step brings the shortest path from the initial point to the final point and the obstacle point is in the connection of two parts of the trajectory; the second stage provides changing the second part of the trajectory by a smooth (polynomial) law, that is connected with the first part at the angle 180 degrees; the third stage allows to add acceleration and deceleration modes of motion to the trajectory and reduces the load velocity when it goes near obstacle point. All of the calculations are carried out in an analytical way, and example of numerical calculations is presented in the article as well. In order to make the needed calculation for shifting and rotation of the smooth part of the trajectory (second stage of calculation) all the path was converted into discreet form. Mentioned operation of rotation was carried pot with a rotation matrix. In order to calculate discreet values of mechanisms' velocities the modified digital Savitzky-Golay filter was applied. The output results may be implemented by means of varied frequency drives of the mechanisms. The article ends with comparing of numerical indicators, which refer to the three stages. Among them are: gaps in the velocity of a mechanism during acceleration and deceleration, the gap in the velocity of a mechanism during obstacle avoidance, and the change in velocity sign of a mechanism. All of the indicators were calculated for both of the mechanisms: tower crane slewing and trolley movement. Comparison of the numerical indicators allowed us to conclude, that the final stage (calculations iteration) is the best among the comparable. However, it has some disadvantages, that need to be fixed in further investigations in this direction.