Tensile Forces In Cables Research Articles

MRI-compatible and sensorless haptic feedback for cable-driven medical robotics to perform teleoperated needle-based interventions.

Surgical robotics have demonstrated their significance in assisting physicians during minimally invasive surgery. Especially, the integration of haptic and tactile feedback technologies can enhance the surgeon's performance and overall patient outcomes. However, the current state-of-the-art lacks such interaction feedback opportunities, especially in robotic-assisted interventional magnetic resonance imaging (iMRI), which is gaining importance in clinical practice, specifically for percutaneous needle punctures. The cable-driven 'Micropositioning Robotics for Image-Guided Surgery' (µRIGS) system utilized the back-electromotive force effect of the stepper motor load to measure cable tensile forces without external sensors, employing the TMC5160 motor driver. The aim was to generate a sensorless haptic feedback (SHF) for remote needle advancement, incorporating collision detection and homing capabilities for internal automation processes. Three different phantoms capable of mimicking soft tissue were used to evaluate the difference in force feedback between manual needle puncture and the SHF, both technically and in terms of user experience. The SHF achieved a sampling rate of 800Hz and a mean force resolution of 0.26 ± 0.22N, primarily dependent on motor current and rotation speed, with a mean maximum force of 15N. In most cases, the SHF data aligned with the intended phantom-related force progression. The evaluation of the user study demonstrated no significant differences between the SHF technology and manual puncturing. The presented SHF of the µRIGS system introduced a novel MR-compatible technique to bridge the gap between medical robotics and interaction during real-time needle-based interventions.

Evaluation of Cable Tension Using Static and Dynamic Test on R.H. Fisabilillah Cable-Stayed Bridge, Batam-Indonesia

R.H. Bridge Fisabilillah (Bridge I) is a cable-stayed bridge, included in the series of Barelang Bridges (Batam-Rempang-Galang) which were built from 1992 to 1998. With the service life of the bridge reaching 25 years, it is necessary to check the health condition of the bridge structure. Bridge cables are one of the most important elements of a cable-stayed bridge. These cable elements dominantly experience tensile forces when transmitting loads from the decks to the bridge pylons. Cable force inspection methods can be carried out through the direct measurement method (e.g. static test using a lift-off method) and indirect measurement (e.g. dynamic test using accelerometer sensors, electromagnetic/EM sensors, and so on). This study aims to compare the cable tensile force based on the static test (lift-off method) in 2017 against the dynamic test (accelerometer sensors) in 2022. Evaluation of the cable tensile force based on the dynamic test was carried out using the taut string theory and beam string theory approaches. From the study, the two empirical approaches yielded insignificantly different results where a difference in the mean difference of -1,71% was found with a maximum difference of 28,15%. The study also shows an increase in cable force capacity to a maximum of 47,20% UTS (ultimate tensile strength) based on the taut string theory and a maximum of 53.37% UTS based on the beam string theory. This value is greater when compared to the results of the cable force based on the static test (lift-off) in 2017, which was a maximum of 41.64% UTS. It is recommended to carry out further and more comprehensive studies to determine the effect of changes in cable force distribution on the behavior of the structure on the R.H. Fisabilillah Bridge.

Experimental research on the aerodynamic responses of a long-span pipeline suspension bridge

The aerodynamic stability performance of a long-span pipeline suspension bridge is studied based on a 1: 25 full-bridge aeroelastic model using wind tunnel tests. The influences of initial angle of attack, pipeline diameter, pipeline number, and turbulence intensity on the aerostatic and buffeting displacements of the girder, and on the wind cable tensile forces are comprehensively investigated. The aerodynamic displacements of the girder along the span were measured by using a video gauge. Analytical expressions are derived to construct the displacements of three-degree-of-freedom motions from the recorded signals, and the differences between the derived formulas and the conventional ones are demonstrated. Recommendations are offered to reduce or even eliminate the potential errors of the convenient habitual formulas. The testing results show that the aerodynamic displacements and wind cable tensile forces of the bridge may depend remarkably on the initial angle of attack, pipeline diameter, pipeline number, and turbulence intensity. Research results of the present work can provide beneficial references for evaluating the wind-resistant performances of bridges of the similar type.

Cable Tensile Forces Associated to Winch Design in Tethered Harvesting Operations: A Case Study from the Pacific North West

Cable tensile forces in winch-assist harvesting have been investigated in order to assess the safety concerns of the technology. However, the literature is lacking, particularly in regards to the impact of winch design. In this study, a Summit Winch Assist tethering a feller-director on ground slopes up to 77% was monitored for four days. The cable tensile forces were simultaneously recorded at the harvesting and anchor machine at a frequency of 100 Hz. Cameras and GNSS devices enabled a time study of the operations and the recording of machine positions. Winch functionality and design were disclosed by the manufacturer and used for the interpretation of the results. The cable tensile forces reached 296 kN at the harvesting machine and 260 kN at the anchor machine. The slow negotiation of obstacles while moving downhill recorded the highest peaks, mainly due to threshold settings of the winch in the brake system activation. Lower but significant peaks were also recorded during stationary work tasks. The peaks, however, were limited to a few events and never exceeded the endurance limit of the cable. Overall, the study confirmed recent findings in cable tensile force analysis of active winch-assist operations and provided evidence of the underlaying mechanisms that contribute to cable tensile forces.

Correction to: Assessment of cable tensile forces in active winch-assist harvesting using an anchor machine configuration

Correction to: Assessment of cable tensile forces in active winch-assist harvesting using an anchor machine configuration

Time history analysis of a tensile fabric structure subjected to different seismic recordings

The structural behavior of a tensile fabric structure, known as hypar, is investigated. Seismic-induced stresses in the fabric and axial forces in masts and cables are obtained using accelerograms recorded at different regions of the world. Time-history analysis using each recording are performed for the hypar by using finite element simulation. It is found that while the seismic stresses in the fabric are not critical for design, the seismic tensile forces in cables and the seismic compressive forces in masts should not be disregarded by designers. This is important, because the seismic design is usually not considered so relevant, as compared for instance with wind design, for these types of structures. The most relevant findings of this study are: 1) dynamic axial forces can have an increase of up to twice the static loading when the TFS is subjected to seismic demands, 2) large peak ground accelerations seem to be the key parameter for significant seismic-induced axial forces, but not clear trend is found to relate such forces with earthquakes and site characteristics and, 3) the inclusion or exclusion of the form-finding in the analysis procedure importantly affects results of seismic stresses in the fabric, but not in the frame.

Assessment of cable tensile forces in active winch-assist harvesting using an anchor machine configuration

The growing interest in accessing steep terrain is pushing the expansion of the operating range of ground-based machines through winch-assist technology. However, cable tensile forces remain a major concern in the advancement of this technology. In this study, cable tensile forces in a winch-assist harvesting operation based on an anchor machine configuration were investigated. A harvesting machine tethered on ground slopes of up to 103% (45.9°) was observed over four days. Cable tensile forces were recorded at both the harvesting and anchor machines, at a frequency of 100 and 10 Hz, respectively. Cameras and GNSS devices enabled the execution of a time and motion study and the recording of machine positions. At the harvesting machine, peak tensile forces of up to 400 kN were recorded. Downhill movements of the harvesting machine were the cause of the highest peaks which, however, never exceeded the endurance limit of the cable. Numerous local variations in cable tensile forces exceeded 50 kN for just a few hundredths of a second, with a maximum variation of 300 kN in less than a second. Movements of the harvesting machine were the main cause of the major local variations. Depending on work element and harvesting machine movements, cable tensile forces were higher at either the harvesting or anchor machines; however, the highest peak tensile forces per work element and the related working loads were always recorded at the harvesting machine. Some implementation steps for improving the safety of winch-assist harvesting operations using anchor machines are also discussed.

Effect of a traction-assist winch on wheel slippage and machine induced soil disturbance in flat terrain

ABSTRACT Recently, forest operations are facing unfavorable climatic conditions more frequently. In Central Europe, machine trafficability and induced soil disturbances are negatively affected by periods of high precipitation and less intensive frost during ground-based harvesting operations. Winch-assist technology is assumed to reduce soil disturbance by forest machines in steep terrain. Still, the potential positive effects of winches to assist traction of forest machines in flat terrain have rarely been surveyed. In this study, a field trial was conducted in flat terrain (slope < 5%). There, a forwarder with an integrated traction-assist was monitored during six consecutive machine passes on a permanent machine operating trail. The first section of the machine operating trail was passed without traction-assist, the remaining section with traction-assist, resulting in two treatment groups. To assess soil impacts, three test plots were positioned per treatment group. Within these plots, pre- and post-operational soil bulk density, soil displacement and rutting were determined. Additionally, wheel slippage and cable tensile force were examined, using incremental rotary encoders and a flexible tensile force measurement kit, respectively. It was observed, that wheel slippage responded inversely with tensile force. Traction-assist technology reduced wheel slippage from 5.3 ± 11.9% to 0.37 ± 10.19% along the section of the machine operating trail, as compared to results from the unassisted section. Although wheel slippage was significantly reduced, no mitigating effect by the usage of traction-assist technology on soil disturbance could be observed, probably due to the low volumetric water content of 27%.

Assessing Cable Tensile Forces and Machine Tilt of Winch-Assisted Forwarders on Steep Terrain under Real Working Conditions

Winch-assisted forwarders are now commonly accepted as an innovative alternative for extracting wood on challenging terrain. In order to assess safety risks, it is necessary to know the tensile forces in the steel wire rope and their interaction with the machine tilt under real working conditions. In this study, the tensile force and the machine tilt of two winch-assisted forwarders (John Deere 1210E and Komatsu 840TX) were observed for about 15 work hours without delays on two different stands in Austria. The tensile force data and the machine tilt data were separated by work elements. The mean tensile force ranged from 18.1 kN for unloading up to 56.8 kN for loading activities. During the measurements, the cable tensile force exceeded 50% of the minimum breaking strength (MBS) only twice. The maximum observed tensile force was 174.5 kN or 82.7% of the MBS, respectively, which led to a failure of the steel cable. For the machine tilt, a maximum of 80% was measured during loading and driving during loading. John Deere 1210E was operated 31% of the productive work time above the manufacturers tilt limit. For Komatsu 840TX, the manufacturers’ maximum tilt limit was exceeded only twice. The study also showed that peaks with an amplitude of up to 50 kN can occur within a few centiseconds, which highlights the need of high measurement rates, when measuring cable tensile force of winch-assisted machinery. The detailed analysis of the peaks showed that 90% of the pit-to-peak amplitudes ≥20 kN occurred during driving activities. Only 10% of pit-to-peak amplitudes ≥20 kN were measured during loading activities, although loading took about 43.5% of the productive work time. As such, the study results confirm that amplitudes of peaks in tensile force, and hence safety risks, are significantly higher during driving than during loading.

Nonlinear vibrations of offshore floating structures moored by cables

In this study, a numerical model is presented for the nonlinear vibrational analysis in the symmetrical plane of the rectangular offshore floating structures moored by cables. The upper end of each mooring cable is connected to the floating structure and the other end is fixed to the sea bed. The nonlinear equations of motions of the mooring cables are derived by using nonlinear cable elements that are formulated based on the extended Hamilton principle. The floating platform is modeled as a rigid body with three degrees of freedom. The forces applied on the floating structure and cables are analyzed, formulated and expressed in details. The connection conditions between the floating structure and mooring cables are introduced to formulate the equations of motions of the system as a whole. The vibrations of the floating structure under horizontal sinusoidal excitation are analyzed numerically. The influence of different sag-to-span ratios or inclined angles of the mooring cables, and that of different current velocities on the displacements of the floating structure and maximum tensile force in the cables are studied. The displacement amplitudes of the moored floating structure and maximum cable tensile force under different current velocities are also studied for different excitation frequencies.

Monitoring Cable Tensile Forces of Winch-Assist Harvester and Forwarder Operations in Steep Terrain

The objective of this case study was to develop and test a specific survey protocol for monitoring tensile forces for winch-assisted harvesters and forwarders with a mounted or integrated constant-pull capstan winch technology. Based on the designed survey protocol, the interactions between work phases, machine inclination, and tensile forces in typical work conditions were analysed. The established workflow, including equipment and the developed analysis routines, worked appropriately and smoothly. The working load on the cable during the study did not exceed 50% of the maximum breaking strength. A maximum tensile force peak at 56 kN was observed during delays for the forwarder, and a peak of 75.5 kN was observed for the harvester, both of which are still within the safe working load when considering a safety factor of two.

Seismic analysis of nonlinear offshore moored floating structures

This article presents a numerical model for solving the nonlinear random vibrations of offshore moored floating structures under seismic excitation. The offshore moored floating structure consists of the floating platform and mooring cables. The floating platform is considered as a rigid body with 3 degrees of freedom. The nonlinear equations of motions of the mooring cables are established using the nonlinear cable elements that are formulated based on the extended Hamilton principle. The nonlinear hydrodynamic drag forces that act on both the floating platform and cables are considered. In order to carry out the random vibrational analysis, the connection conditions between the floating structure and mooring cables are given to formulate the equations of motions of the whole system. Finally, the moored floating structure under horizontal seismic ground accelerations with Kanai–Tajimi model are analyzed using Monte Carlo simulation method. The probability density functions of the displacements of the moored floating structure and the maximum tensile force in cables are presented. The influences of different sag-to-span ratios or inclined angles of the mooring cables on the mean value and standard deviation of the displacements of the floating structure and the maximum tensile force in cables are analyzed.

Probabilistic Statistical-based Method for Measuring Tensile Forces in Hollow Steel Strand Cables

Probabilistic Statistical-based Method for Measuring Tensile Forces in Hollow Steel Strand Cables

Experimental and Numerical Investigation of Axially Preloaded Carbon Fiber Cable Vibration

AbstractFor structures deployed in space using cables in which vibration damping is critical for structural stability, the understanding of cable damping is particularly significant to the structural performance. This paper describes an experimental setup for the measurement of cable vibration damping under varying cable tensile force, length, and configuration. The damping is determined by the half-power bandwidth method and the logarithmic decrement method. The testing results showed that the cable damping is related to cable tension, length, and configuration. A finite-element model is presented to simulate cable vibration and cable damping. The natural frequencies of the tested cables are determined by spectral analysis and agree well with those of finite-element simulation and theoretical analysis. The time history responses recorded by the accelerometers agree well with those from the finite-element simulation, which demonstrates that selected elements are capable of modeling the dynamic response of...

Vision-based monitoring system for evaluating cable tensile forces on a cable-stayed bridge

Because of the characteristics of cable-supported bridges, the cable tensile force is considered a critical item in their maintenance. In particular, because the evaluation of the cable tensile force in a cable-stayed bridge is essential for understanding the general status of the structural system, identifying the initial values of this force in the construction of a bridge and then accurately predicting and comparing its estimated values during traffic use are very important tasks for the maintenance of a cable-stayed bridge. Therefore, in this study, a vision-based monitoring system that utilizes an image processing technique was developed to estimate the tensile force of stay cables during traffic use. A remotely controllable pan-tilt drive was installed in the developed vision-based monitoring system to estimate the forces on multiple cables using a single system. The use of a 20× electric zoom lens made it possible to achieve sufficient resolution to remotely derive the dynamic characteristics of the stay cables.

Direct Geometrico-Static Problem of Underconstrained Cable-Driven Parallel Robots With Three Cables

Abstract This paper studies the direct geometrico-static problem (DGP) of underconstrained cable-driven parallel robots (CDPRs) with three cables. The task consists in determining the end-effector pose and the cable tensile forces when the cable lengths are assigned. The problem is challenging, because kinematics and statics are coupled, and they must be tackled simultaneously. An effective elimination procedure is proposed and a least-degree univariate polynomial free of spurious factors is obtained in the ideal governing the problem. This is proven to admit 156 solutions in the complex field. Several approaches for the efficient computation of the complete solution set are presented, including an eigenproblem formulation and homotopy continuation.

Unwinding characteristics of thin cables for inner and outer dispensers

When thin cables of materials such as yarn and tether are unwound from a spool dispenser, various balloon shapes are generated depending on the initial tensile force at the guide-eyelet point. The shapes are dependent on the properties of the cable because the point of unwinding depends on the thickness of the cable. In this paper, the unwinding characteristics are analyzed for inner and outer dispensers by using three types of thin cable. The dimensionless steady-state equation of motion is first derived from Hamilton’s principle for an open system and the perturbation scheme. The second-order differential equation is then solved by means of shooting method because the boundary conditions at the lift-off point are not fully sufficient. Several parameters such as cable diameter and initial tensile force are checked to study their effects on the balloon shapes. For a given material, the larger is the diameter of the cable, the higher is the air-drag coefficient on the cable, and the effect of the centrifugal force is weaker than that of the fluid resistance. Moreover, the maximum radius of the balloon and the total length of the control volume are small when the cable is thick.

Application of Laser Vibrometer to the Measurement and Control of Cable Tensile Forces in Cable-Stayed Bridges

The tensile forces acting on the cable of long-span bridges are one of the most important factors since they reflect not only the structural stability of cables but also the overall quality of construction. Currently, indirect measurement using accelerometers attached to the surface of the cable is widely used to measure the natural frequency of cable. The frequency obtained from the accelerometer is converted to the tensile force of the cable. However, it sometimes requires many hazardous labors such as attaching the device on the surface of cable and wiring it with data logger, which could hinder the safety of workers during the erection of cables. In this study, a method using laser vibrometer is introduced to measure the tensile forces on cables at a distance. In addition, this study developed a unique postanalysis computer program that can calculate the tensile forces in real time. Compared with the values obtained from the accelerometers, the laser vibrometer system provided accurate and reliable matching.

Analysis of Parameters' Sensitiveness of Long-Span Hybrid Girder Cable-Stayed Bridge

In order to improve the construction control precision of long-span hybrid girder cable-stayed bridge, the design parameters such as the weight of girder, the cable tensile force and the stiffness of cable are conducted sensitivity analysis through computing and comparing the influences of these parameters on the deflection of girders, the stress of girders and the cable force in the bridge's completion state. It was shown by the computation results that the main parameters of long-span hybrid girder cable-stayed bridge are the weight of girder and the cable tensile force, the stiffness of cable has a little influence on the completion state of the bridge. With this approach, through modifying the main parameters, while ignoring the influences of the secondary ones, the Jingyue Yangtze River Highway Bridge construction control has been successfully done. The test results show that the cable force and the contour of the bridge are in good state. They are both in the range of control, the relative error of the cable force is less than 3% and the elevation deviation is less than 5mm.

Determination of Forces in Roof Cables at Administrative Center Amazon Court

Abstract There are a number of building structures in service in Czech Republic at present time where the main structural element is a cable or a suspender, for example: cable roofs, cable-stayed bridges and bridges with external prestressing cables. Knowing the value of cable tensile force is important for appreciation of reliability both during their construction and their operation. The vibration frequency method can be used for indirect estimation of the cable tensile force using the measured natural frequencies. The vibration frequency method is very suitable for experiments done only one time or occasionally. This method provides results precise enough for suitable setting of experiment and evaluation method. The vibration frequency method is often used in practice because it provides an efficient, cheap and relatively easy way to determine the cable forces and a standard measuring line for dynamic experiments can be used. The paper will present the results of an experiment carried out on the roof structure of the Administrative Center Amazon Court .The results of the experiment show that production tolerances and mounting method can significantly influence the stresses in statically indeterminate load bearing structure with cables. Therefore, it is important to verify forces in cables experimentally in these structures and it is also suitable to monitor forces during their service life.