Force Measurement Method Research Articles

Numerical investigation on the evolution process of hydraulic transport and overcurrent blockage of silted urban rainwater pipelines: An approach based on computational fluid dynamics and discrete element method

During urban flood events, the effect of urban rainwater pipeline siltation on overflow and stagflation intensifies the severity of flood disaster. However, the dynamic coupling mechanism of pipeline sedimentation and water flow is still unclear. To investigate the influence of two-phase flow on the hydraulic transport of siltation particles in rainwater pipelines, the numerical simulation model based on computational fluid dynamics (CFD) and discrete element method (DEM) is constructed. Then, the transient continuity governing equation and conservation equation of momentum are formulated to provide dynamic guidance and boundary constraint for CFD-DEM simulation. On this basis, the optimal drag force model and measurement method of equivalent siltation degree of pipeline are proposed and nested with CFD-DEM, and then, a high resolution numerical simulation model of pipeline sedimentation is formulated. The results show that the siltation degree affects the efficiency of drainage pipeline to a degree of 47%, which is much greater than the degree of influence of 33% for siltation length and 18% for slope. When the siltation degree is 0.1, the thickness of the silted bed surface under the influence of water flow scour is reduced by 33%. It revealed that the influence degree of siltation degree and flow rate was 168% and 20%, respectively, which was much larger than that of siltation length and slope. This study can provide technical support for subsequent pipeline cleaning and maintenance as well as flood prevention and mitigation.

Design of an Innovative Method for Measuring the Contractile Behavior of Engineered Tissues.

Hypertrophic scarring is a common complication in severely burned patients who undergo autologous skin grafting. Meshed skin grafts tend to contract during wound healing, increasing the risk of pathological scarring. Although various technologies have been used to study cellular contraction, current methods for measuring contractile forces at the tissue level are limited and do not replicate the complexity of native tissues. Self-assembled skin substitutes (SASSs) were developed at the "Centre de recherche en organogénèse expérimentale de l'Université Laval/LOEX" and are used as permanent full-thickness skin grafts. The autologous skin substitutes are produced using the self-assembly method, allowing the cultured cells to produce their extracellular matrix leading to a tissue-engineered substitute resembling the native skin. The level of contraction of the SASSs during the fabrication process is patient-dependent. Thus, because of its architecture and composition, SASS is an interesting model to study skin contraction in vitro. Unfortunately, standard measurement methods are unsuited for SASS contraction assessment, mainly due to incompatibilities between the SASS manufacturing process and the current contraction force measurement methods. Here, we present an innovative contraction measurement method specifically designed to quantify the contractile behavior of tissue-engineered substitutes, without disrupting the protocol of production. The method uses C-shape anchoring frames that close at different speeds and magnitudes according to the tissue contractile behavior. A finite element analysis model is then used to associate the frame deformation to a contractile force amplitude. This article shows that the method can be used to measure the contraction force of tissues produced with cells displaying different contractile properties, such as primary skin fibroblasts and myofibroblasts. It can also be used to study the effects of cell culture conditions on tissue contraction, such as serum concentration. This protocol can be easily and affordably applied and tuned to many regenerative medicine applications or contraction-related pathological studies. Impact Statement The protocol presented in this article is a new and simple method to quantify contraction forces present in tissue-engineered substitutes. Using finite element analysis, it allows for the measurement of a contraction force rather than a surface reduction as usually provided by other tissue contraction measurement methods. The results shown are in correlation with the current literature relevant to tissue contraction. It can be easily implemented, and hence, this method will open up new avenues to study tissue contraction of living substitutes engineered with various cell types and to optimize culture conditions.

Simulation and Modelling of a Precision Method for Static Low Force Measurement

Simulation and Modelling of a Precision Method for Static Low Force Measurement

Force Measurement Technology of Vision‐Based Tactile Sensor

Marker‐type vision‐based tactile sensors (VTS) realize force sensing by calibrating marker vector information. The tactile visualization can provide high‐precision and multimodal force information to promote robotic dexterous manipulation development. Considering VTS's contribution to force measurement, this article reviews the advanced force measurement technologies of VTSs. First, the working principle of marker‐type VTSs is introduced, including single‐layer markers, double‐layer markers, color coding, and optical flow. Then, the relationship between the marker type and the category of force measurement is discussed in detail. On this basis, the process of marker feature extraction is summarized, including image processing and marker‐matching technologies. According to the learning approach, force measurement methods are classified into physical and deep learning models. Further, branches of each method are analyzed in terms of input types. Combined with measuring range and precision, the correlation of sensor design, materials, and recognition methods to force measurement performance is further discussed. Finally, the difficulties and challenges are analyzed, and future developments are proposed. This review aims to deepen understanding of the research progress and applications and provide a reference for the research community to promote technology generations in related fields.

A spatial six-dimensional force measurement method based on acceleration sensors

Accurate measurement of disturbance forces is an essential prerequisite for the simulation and analysis of micro-vibrations of space optical devices. Most of the current force measurement methods are based on force sensors, which have problems such as serious coupling between sensors, and the measurement accuracy is easily affected by the preload force. In order to solve these problems, a six-dimensional disturbance force measurement method based on acceleration sensors is proposed in this paper. First, the basic structure of the force measurement platform is introduced, and then the dynamics model of the platform is established and its force measurement principle is analyzed. Then the simulation analysis of the measurement accuracy of the platform is carried out by the Monte Carlo method. The analysis results show that the measurement accuracy of the disturbance force is proportional to the measurement accuracy of the acceleration sensor and the mass matrix recognition accuracy. When the errors of the acceleration sensor and mass matrix are within the normal range, the measurement error of the force measurement platform is less than 15%. Finally, a single-degree-of-freedom disturbance force measurement verification platform is built, and the test results show that the disturbance force is basically proportional to the acceleration of the platform when it is far from the resonance frequency, which verifies the correctness of the method to a certain extent. The measurement method is simple in structure and easy to implement, and can perform real-time measurement. Moreover, the measurement frequency is wide and the resolution is high, which is suitable for the measurement of disturbance force in the form of sinusoidal vibration or multi-frequency line spectrum.

FBG-based force sensing with temperature self-compensation for smart bolts

Small variations in bolt component connection can have significant impacts on equipment operating safety and efficiency. A comprehensive understanding of the bolted status supports the equipment optimizing in in-situ health monitoring. Therefore, an improved bolt force measurement method is looking forward. Given the minimally invasive nature, potential for multi-parameter measuring, and ability to operate in harsh conditions, optic fiber sensors present an opportunity for equipment in-situ health monitoring. This paper first strengthened the confidence in embedding optic fiber force sensors within the bolts. Additionally, the FBG temperature self-compensation method is employed and successfully improved the force measurement accuracy, compared with the existing studies. The smart bolt configuration (addictively manufactured) refers to the standard bolt dimensions and integrates a metallized FBG optical fiber with a diameter of less than 0.5 mm. Then, the sensor performance was investigated through a series of routine mechanics tests and reports the force sensitivity of the designed smart bolt is 13.06 pm/kN (for M10 bolts) and 14.59 pm/kN (for M12 bolts), respectively. In dynamic force loading tests, the error of the sensor is within 4.95 %, and the maximum force detection error after temperature compensation is within 8.03 %, indicating an improved bolt force measuring accuracy. The anti-creep and anti-torque interference tests were undertaken to confirm the designed smart bolts are adequate for long-term service. The bolt vibration and connection test results have proved the mechanical solidity and reliability under extreme working conditions. This investigation confirms the viability of installing optic fiber force sensors in a bolt component. Confidence was established that the smart bolts have the advantages of compact structure, improved force detection accuracy, good reliability, and support for modern equipment in-situ health monitoring.

Investigation of wind loads on angle steel columns in lattice structures via force measurement method on members

As the demand for precise prediction of fatigue and collapse continues to grow, it is imperative to conduct research on wind load calculation methods for lattice structures using members as the fundamental unit. This study focuses on the tower body of an angle steel lattice structure with a rectangular cross-section. The aerodynamic characteristics of entire segments, column members in lattice structures, and a single angle steel were investigated, along with the aerodynamic interference effects on members within lattice structures. The research findings indicate that drag coefficients cannot universally substitute the SRSS coefficients of column members or a single angle steel across all wind directions. Therefore, considering that the drag coefficient of the column member or single angle steel surpasses 98% of their SRSS coefficients at a wind direction of 45°, a particular skewed wind load factor was defined, and its fitting formula was proposed. Additionally, a calculation method for wind loads on columns within lattice structures was developed, introducing the concepts of SRSS angle and aerodynamic interference factors on members. The comparison among the experimental data, fitting formula, and proposed calculation method, were conducted. To facilitate the practical application, the simplified formulas for both AIF and SRSS were recommended.

A comprehensive study on temple clamping force for eyeglasses design: from measuring to modelling

Abstract A key factor in determining the comfort level of eyeglasses is the clamping force at the temple. However, how to accurately measure and estimate the clamping force remains under-explored. Hence, to address this gap, we proposed a novel temple clamping force measurement method with a digital tension meter and developed a mathematical model to calculate the clamping force of the temples based on eyeglasses parameters (including length, one-side displacement, and flexural rigidity of the temples). To validate our method, we collected the simulated and physical datasets of different eyeglasses and conducted a multiple regression analysis to calculate the model parameters. The experimental results demonstrated the accuracy and reliability of the proposed method. This model can guide us in customizing the parameters of the eyeglasses to produce comfortable clamping forces for the users. Our codes and data will be publicly available at: https://github.com/Easy-Shu/Eyeglasses_Force_Modelling.

Rapid measurement method for cable tension of cable‐stayed bridges using terrestrial laser scanning

AbstractThis study proposes a new method for the rapid and non‐contact measurement of cable forces in cable‐stayed bridges, including a cable force calculation method based on measured cable shapes and a batch acquisition method for the true shape of cables. First, a nonlinear regression model for estimating cable forces based on measured cable shapes is established, and a Gauss–Newton‐based cable force solving method is proposed. Furthermore, terrestrial laser scanning technology is used to collect geometric data of the cables. Meanwhile, automatic segmentation, noise reduction, and centerline extraction algorithms for the cable point cloud are proposed to accurately and efficiently obtain the cable shape. The correctness of the proposed cable force calculation method is verified in a well‐designed experiment, with the measurement error of cable forces for 15 test samples being less than 1%. Finally, the proposed point cloud automation processing algorithm and cable force measurement method are fully tested on a cable‐stayed bridge with a span of 460 m. The measurement accuracy of the proposed method for actual bridge cable tension is comparable to that of the frequency method, but the detection efficiency on site is nine times higher than that of the traditional frequency method. Overall, this study provides a new measurement method for construction control, health monitoring, intelligent detection, and other fields of cable‐stayed bridges.

Study on the sealing performance of high-pressure flanges by a magnetic measurement method of bolt axial force

Under high-pressure conditions, flange sealing often fails due to inadequate bolt pre-tension, leading to unstable pressurization or leakage. Assessing the integrity of high-pressure flange sealing presents challenges, constrained by operational conditions, complex equipment integration, and associated costs. This study introduces a method to evaluate flange sealing using magnetic measurements of bolt axial forces. A novel device developed using the magnetoelastic method efficiently and conveniently measures these forces under various internal pressures. The results show a linear relationship between magnetic signals and bolt axial forces at nominal pressures, whereas excessively high pressures cause anomalous changes in magnetic signals, indicative of bolt plastic deformation. Finite element simulation analyzed the changes in bolt axial force and gasket contact stress due to internal pressures, leading to an empirical formula that correlates these variables under varying pressures. The study also explored the impact of uneven pre-tensioning and gasket material on sealing contact stress. A sealing contact surface model, established based on actual roughness profile parameters, enabled the simulation and formulation of an exponential relationship between contact stress and sealing clearance. This foundation facilitated the creation of a leakage prediction model that incorporates bolt axial force parameters, thus enabling a quantitative assessment of flange sealing performance. This research provides a practical approach to evaluating the sealing performance of operational high-pressure flanges.

Electrical measurement method of static friction force on rough surface

Friction plays a key role in the assessment of the safety and stability of mechanical systems (such as superconducting magnet quench explosion, aerospace vehicle bearing wear, etc.). Due to the closeness of the interfaces in engineering structures and the randomness of the contact surfaces, existing methods for measuring static friction force are unable to measure it at the contact interfaces of engineering structures under service conditions. In this paper, a new method for measuring the static friction force at the interface based on electrical signals is proposed. This method enables the measurement of the static friction force at interfaces of complex engineering structures under service conditions solely through electrical signals. The results indicate that the contact resistance gradually decreases with the increase in tangential load during the static friction stage until a monotonic behavior of macroscopic sliding occurs. The evolution of contact resistance is linked to the evolution of the real contact area, and this monotonic behavior can be explained as the deformation form of contact points. The accuracy of the proposed electrical measurement method is verified by comparison with experimental results (with an error of less than 9%). The indirect measurement method of friction force proposed in this paper can effectively measure the static friction force at the interfaces of engineering structures under service conditions, and it is expected to be applied to the detection of friction performance at engineering structure interfaces in extreme service environments.

Thermodynamic Assessment of Molten Bix-Sn1-x (x = 0.1 to 0.9) Alloys and Microstructural Characterization of Some Bi-Sn Solder Alloys.

Properties such as lower melting temperature, good tensile strength, good reliability, and well creep resistance, together with low production cost, make the system Bi-Sn an ideal candidate for fine soldering in applications such as reballing or reflow. The first objective of the work was to determine the thermodynamic quantities of Bi and Sn using the electromotive force measurement method in an electrolytic cell (Gibbs' enthalpies of the mixture, integral molar entropies, and the integral molar excess entropies were determined) at temperatures of 600 K and 903 K. The second objective addressed is the comprehensive characterization of three alloy compositions that were selected and elaborated, namely Bi25Sn75, Bi50Sn50, and Bi75Sn25, and morphological and structural investigations were carried out on them. Optical microscopy and SEM-EDS characterization revealed significant changes in the structure of the elaborated alloys, with all phases being uniformly distributed in the Bi50Sn50 and Bi75Sn25 alloys. These observations were confirmed by XRD and EDP-XRFS analyses. Diffractometric analysis reveals the prevalence of metallic Bi and traces of Sn, the formation of the Sn0.3Bi0.7, Sn0.95Bi0.05 compounds, and SnO and SnO2 phases.

Experimental study on the aerodynamic characteristics of combined angle transmission tower subject to skew wind

The transmission towers served as crucial carriers in the process of power transmission. The combined angle transmission tower of dual-angle steel with cruciform section are relatively a novel type of angle tower, which is being more widely used in transmission lines. The studies on aerodynamic characteristics of combined angle tower in skewed wind are limited. In this paper, the wind tunnel tests are conducted to investigate the aerodynamic characteristics of the combined angle tower, and the high frequency force balance (HFFB) test is introduced to obtain the transverse and longitudinal forces on the tower using the direct force measurement (DFM) method. The drag coefficients and wind load-distribution factors of the combined angle tower are obtained from the wind tunnel tests, and the effects of interference and tower leg spacing on the wind loads of the tower legs are fully explored. It can be found that the aerodynamic coefficients and drag coefficients of the combined angle steel tower leg tend to decrease with the increase of interference members and it also decreases with the decrease of the tower leg spacing. The test wind load-distribution factors of the isolated leg are generally larger than those defined by seven typical codes (e.g., US, EU, Japanese, and Chinese codes) and significantly exceed the code-specified values under partial wind angles. The observations obtained from this study may provide helpful guidance on the wind-resistant design of this relatively novel type of combined angle tower.

Experimental verification and rapid estimation of uncalibrated cable force via video-based and vibration-based measurements.

The stayed-cable is an important component of cable-stayed bridges, with cable force being a focal point during construction and bridge operation. The advancement of camera and image processing technology has facilitated the integration of computer vision technology in structural inspection and monitoring. This paper focuses on enhancing cable force measurement methods and addressing the limitations of traditional testing techniques by conducting experimental research on cable force estimation using video recording. The proposed approach involves capturing video footage of the target on the cable with a smartphone. Subsequently, a combination of techniques such as the background subtraction method, image morphology processing, and Hough transform image processing technology are employed to detect the precise center coordinates and ultimately obtain the accurate displacement-time curve of the cable's vibration. In addition, the graphic Circularity Coefficient (CC) has been introduced to assess its effectiveness in post-motion-blur image processing for circular targets. The fundamental frequency of the cable is determined by the fast Fourier transformation, and the relationship between the cable force and the fundamental frequency is used to estimate the cable force. The experimental results are compared with data from accelerometers and force gauges, demonstrating that the frequency measurement error is below 1.2% and the cable force test error is less than 3%. In the process of acquiring the cable's fundamental frequency, the test directly employs the pixel as the displacement unit, eliminating the need for image calibration. The innovative use of the CC in processing motion-blurred targets ensured accurate recognition of target coordinates. The experimental findings highlight the method's simplicity, speed, and accuracy.

THERMODYNAMIC STUDY OF THE CdSb COMPOUND BY THE ELECTROMOTIVE FORCE MEASUREMENTS METHOD

Thermodynamic properties of CdSb binary compound were determined using an electromotive force measurement (e.m.f.) method with a liquid electrolyte in the ~300-450K temperatures interval. Equilibrium alloys from the CdSb+Sb phase region of the Cd-Sb system was analyzed by means of the e.m.f. measurements. Phase compositions of all samples were controlled using powder X-rays diffraction method. The partial molar functions of cadmium in alloys, the standard thermodynamic functions of formation, as well as the standard entropy of the CdSb compound were calculated. A comparative analysis of obtained results with literature data was performed.

Industrial Soldering Process Simulator

Determination of the physico-chemical interactions between liquid and solid substances is a key technological factor in many industrial processes in metallurgy, electronics or the aviation industry, where technological processes are based on soldering/brazing technologies. Understanding of the bonding process, reactions between materials and their dynamics enables to make research on new materials and joining technologies, as well as to optimise and compare the existing ones. The paper focuses on a wetting force measurement method and its practical implementation in industrial applications. Soldering simulation is a process in which simulation tools are used to model and simulate soldering processes. With simulation, different soldering methods and parameters can be tested to identify the best approach and minimize the risk of errors and failures in the real process. Soldering simulation can be used to optimize the soldering process and increase productivity, as well as to train personnel.

Prediction method for bridge buffeting responses based on the integrated transfer function identified via segmental model vibration test

On the basis of the definition and the three-dimensional characteristics of an integrated transfer function, the transfer function identification method based on reasonable technical means considering the three-dimensional effect was proposed. An original method to predict the bridge buffeting responses directly using the integrated transfer function is presented and investigated by means of segmental model vibration tests. Taking a suspension bridge as the background, the integrated transfer function was identified using segmental model vibration tests, and the effect of span-width ratio on it was studied. The buffeting response test of a full-bridge model was carried out in two different wind fields. Further, the identified integrated transfer functions were applied to predict the buffeting responses of the full-bridge model. By comparing the results, it is demonstrated that the method using reasonable segmental model vibration tests to obtain the integrated transfer functions to predict the bridge buffeting responses was highly accurate. The feasibility of the proposed method according to segmental model vibration tests was verified through tests for the first time. The method can effectively improve the deviation of results arise from the inaccurate simulating of turbulent characteristics in the tests, and avoid the many limitations of pressure and force measurement methods.

ACAM-FoC: A Deep Neural Network Augmented From CAM-FoC to Measure the Grip Force of Mass-Produced Elongated Surgical Instruments

Learning-based grip force measurement methods in robot-assisted minimally invasive surgery (RAMIS) outperforms the traditional model-based methods and avoids the application issues of sensor-based approaches. However, few studies have investigated the problem of grip force measurement in mass-produced surgical instruments. This letter takes the difference in motion hysteresis and mechanism friction among mass-produced surgical instruments into account, and proposes a novel learning-based method ACAM-FoC. ACAM-FoC is an augmentation of CAM-FoC, which is a high accuracy lightweight network proposed in our preceding research. Loss function monotonicity limitation is introduced to alleviate the negative effect of unbalance training data. Offiline experiments are conducted to verify the effectiveness and the advantages over other two existing methods. Online experiments on the self-developed surgical robot system are conducted to preliminarily realize and verify the grip force measurement and feedback in real time. The results support the importance of grip force feedback in leader-follower operation tasks.

Design Method for Automatic Assembly Production Line of Electric Valves in Space Propulsion Systems

This article proposes a design method for a valve automatic assembly production line in response to the automation assembly requirements of electric valve products in space propulsion systems and the engineering problems of inaccurate loading force control and low valve measurement accuracy in existing process methods. This method can achieve five assembly processes during the assembly process of electric valves, including pre-tightening force control, valve-core stroke measurement, performance testing, and shell structure welding. The article introduces the design of platform components such as process execution, positioning, and transportation, as well as the design and operation process of workstations. By combining the design of a three-axis motion mechanism, a small turntable, and a robotic arm, the product can achieve professional, positioning, full process automation, and equipment miniaturization design across multiple workstations. Through the design of precise control of loading force and non-contact optical measurement method of moving structure, compared with the original method, the parameters affecting product performance are precisely controlled and the precision is improved. And the multivariable decoupling of valve product performance is realized by this method. Through application verification, this automatic assembly production line can significantly improve the assembly efficiency of electric valve products and solve difficult problems in product engineering.

Fast and robust vision-based cable force monitoring method free from environmental disturbances

For long-term vision-based cable force monitoring, it is essential to fully consider different types of challenges, such as complex backgrounds in the field of view, illumination changes, occlusion, camera motion, and real-time realization. To address these challenges, this study proposes a vision-based, robust real-time cable force measurement method. In terms of innovation, three unique aspects were incorporated. First, to solve the difficulty of cable edge recognition caused by complex backgrounds, a linear feature detection operator called edge drawing lines was optimized by setting screening strategy based on the slope and line segments length. Second, the average of bilateral edge displacements was used as the final value to offset the displacement deviation caused by the illumination change. Third, to overcome obstacles to identifying the cable frequency caused by the camera motion, an interference frequency elimination method without reference targets or additional sensors was proposed. Furthermore, the integrated cable force calculation method was developed into a real-time measurement software. Finally, the proposed method was applied to a long-span cable-stayed bridge, where the camera was vibrated by the bridge deck or the wind significantly. The reliability of the proposed method was proved by comparing the results obtained with those achieved by accelerometers.