The QuantumPascal (QP) project combines the capabilities of 12 European institutions to enable traceable pressure measurements utilizing quantum-based methods that evaluate the number density instead of force per area to target the wide pressure range between 1 Pa and 3 MPa. This article summarizes the goals and results since the project start in June 2019.
1 kNm universal torque calibration machine with reference torque transducer was established at National Measurement and Calibration Center (SASO / NMCC) in 2019. Torque values are generated over reference torque transducers by means of a servo motor. An air bearing and torque arm are equipped with machine. It is possible to calibrate torque transducer, torque wrench with high accuracy and...
This paper introduces the principle, structure and function of 200kNm large torque standard machine, as well as the main technical design scheme of the machine and the measurement uncertainty of the whole machine. The machine adopts the static weight structure, breaking the knife-edge supporting technology of high sensitivity, and broke through the lever beam micro jack-up, balancing...
50 Nm torque standard machine was established at National Measurement and Calibration Center (SASO / NMCC) in 2019. Realization of torque unit is based on the definition of torque and directly traceable to the mass and length units. It is performed by a lever arm and dead weights system. The lever arm is symmetric and supported by an air bearing. Dead weights, which are under the influence...
This paper promotes the artifact method for determining air density for weighing and mass calibrations in industrial mass calibration laboratories. Substantial economic advantages of the artifact method are identified compared to the traditional method based on measurements of air pressure, temperature and humidity. Artifact prototypes were manufactured and air density was determined using...
The mass comparator is the main measuring instrument for weight value transmission, and there is no unified understanding of how its calibration results are applied to mass value transfer. This article analyzes the main factors affecting the calibration results of the quality comparator and the requirements for measuring instruments in the international recommendation OIML R111-1. The...
Force traceability in hardness measurements is provided via force measurement devices which are requested to have an accuracy class 0.5 for hardness calibration machines, an accuracy class 1 or 0.2% for hardness testing machines according to ISO 376 as indicated in the relevant ISO hardness standards [2], [3], [5], [6], [8], [9]. The most accurate way of having force traceability is to have...
In this presentation the setup of a Swedish NMI for gravimetry is described. It will be a distributed system involving three independent organizations to share the workload and optimize the national resources focusing on the different skills, needs and resources in Sweden.
This work presents a new tiltmeter that utilizes the principle of electromagnetic force compensation (EMFC) in order to increase its measurement range compared to an uncompensated pendulum tiltmeter. The development included investigations on the design of the pendulum mechanics, the position sensor and the actuators. With the chosen parameters a resolution of 1 μrad in a measurement range of...
The 18SIB04 QuantumPascal EMPIR project aims to achieve quantum-based pressure standards. One of the most promising ways of achieving this goal is the use of a Fabry-Perot interferometer to measure the refractivity of the involved gas.
The refractivity and the pressure of the gas are related by the Claussius-Mossotti and Lorenz-Lorentz formal relations. However, these relations are...
Calibrating leak rates using a constant-volume flowmeter consists in measuring the pressure rise rate produced by the leak throughput in a measurement volume. When the leak rates to be determined are low, the latter should be as small as possible, and since it is composed of dead volumes of the tubing, the valves, the gauge, etc., one needs to determine this dead volume accurately. This paper...
Abstract
This paper describes an absolute time based concept to simultaneously calibrate a large number of MEMS Sensors using Ethernet as communication interface, and investigates new uncertainty influences related to the absolute time base.
Keywords: multi sensor calibration; MEMS; Accelerometer; absolute time; Dynamic calibration
When evaluating the performance of measuring technology for mechanical quantities based on strain gauges, one feature stands out above all else: the possibility to realize the smallest measurement uncertainties when building-up precision measuring chains. In this article, advances in the determination of uncertainty of precision measurement chains based on strain gauges, always with the...
This paper describes the investigations of alignment effects and the influence of force transducer creep in conventional hardness tests performed on GUM’s deadweight-type Rockwell Hardness Standard Machine (HSM), Vickers Hardness Machine (HM), Brinell HM and INRiM’s Primary Hardness Standard Machine (PHSM).
This paper provides an overview of the participation of INMETRO on interlaboratory comparisons along the last years and analyses the benefits of having an active participation in such activities.
The calibration of a pressure balance implies to determine the values of $A_0$ and the pressure distortion coefficient $λ$ that defines the piston cylinder–assembly effective area $A_{pi}$. In order to analyze this behavior, this work compares the method of ordinary least squares with the generalized least squares and weighted least squares to calculate the contributions to type A uncertainty,...
With the development of science and technology, more and more equipment are facing the problem of service under extreme temperature. With the increase of temperature, the properties of materials often change, which leads to the failure state of materials at high temperature. However, the existing material testing methods, such as hardness, are mainly based on the traditional normal temperature...
Outgassing effect in a Fabry-Perot cavity based optical pressure standard (OPS) developed at NIM was studied at low pressures using pressure rising method. The pressure rising curve was recorded by the OPS and a calibrated pressure transducer simultaneously. The pressure inferred by the OPS was dependent on the gas refractivity parameters, and showed difference to the transducer. From the...
The traceability of torque measurement in test benches for electrical machines is primarily established by the calibration of the torque transducer. However, the measurement chains and signal processing methods are generally different for the torque calibration and the torque measurement in the test bench. Therefore, the applicability of the calibration should be clarified, before applying the...
This paper describes a kind of automatic weighing instruments product circulation test system. The system is composed of 4 conveyor belts and 4 hopper scales which adopts the "M" type cycle architecture and the principle of superimposed control weighing instruments. Through this system, we can carry out the product test of belt weighers, automatic gravimetric filling instruments and totalizing...
The article describes the possibilities of calibration the force constant in an electromagnetic force load cell (EMFC) using the electrostatic force compensation principle. The static and dynamic principles of calibration of the Kibble balance for the electrostatic force constant, as well as calibration by means of compensation of the electrostatic force by the electromagnetic force, are...
This paper describes a new method to measure the height of the center of gravity of high-sensitive mass artifacts. A measuring device is presented and tested with mass samples of various shapes and densities. The results of the measurements are compared to the geometrical estimated heights of the center of gravity and further developments of the new instrument are presented.
The Centre of gravity of OIML R111 shaped weights was determined by geometric models. Localization of the center of gravity was compared against the experimental determination. The results show that it is not necessary to do the experimental determination of the centers of gravity if geometric measurements of the weights are available because the improvement in the uncertainty does not worth...
Using a transportable Fabry-Pérot cavity refractometer, a circular comparison of existing primary standards at several national metrology institutes has been carried out. This presentation will provide information about the refractometer, its mode of operation, transportation, and performance. Results of the comparison will be presented.
This paper presents the recent development and preliminary results of a compact laser refractometer based on a dual Fabry-Pérot scheme at 1550 nm for infrasound dynamic pressure measurements. The measurement of the beat frequency between two servo-locked lasers onto two Fabry-Pérot cavities allows to track the variation of the refractive index of air, and thus estimate pressure inside the...
With the increasing use of reference torque wrenches, the calibration of reference torque wrenches is also increasing. Many laboratories are equipped with dead-weight torque standard machine, our laboratory designed and built a reference torque standard machine. This paper describes the reference torque wrench calibration comparison experiment between this reference torque standard machine and...
In order to investigate the best way to determine the diagonal length of a Vickers indentation, bright-field (BF), dark-field (DF), differential interference contrast (DIC) and confocal scanning microscopy is utilized to observe indentations on various samples. Each of BF, DF and DIC methods has advantage and disadvantage and evaluated values should be considered carefully. 3D feature of...
This paper describes a comparison of simultaneous continuous force introduction to two strain-gauge force transducer in a force calibration machine. The continuous force was generated by a single loading/unloading step of the full load of the 1 kN dead-weight force calibration machine. Loading rates from 0.3 kN/s to 3.8 kN/s were applied. The results are presented for different loading speeds...
The subject of this article is the development of innovative construction solutions as well as the determination of metrological parameters of the robotic mass comparator with 1 µg resolution. The instrument is intended for mass standards from 10 g up to 200 g.
The described construction, being an innovation when compared to other robotic mass comparators, has enabled the use of a suspended...
In this paper, different force transducers are investigated with regard to their creep behaviour at different load levels. Based on fast loading and creep tests, a method for determining a creep correction factor is presented. For this purpose, creep models based on exponentially decaying functions and an iterative algorithm which takes into account the history of the force-time-profile are...
From the standpoint of a manufacturer specializing in hardness reference blocks, the current status of hardness reference blocks and the concept of hardness standard are explained based on the technical background.
We developed a method of density measurement of pressure transmitting media at high pressures by precisely detecting head differential pressure. To apply this method to other liquids, a pressure interface is newly introduced in the system. As test liquids, we focused on volatile liquids, which are used for pressure gauge calibrations in the case that the gauges need oil-free and/or water-free...
This paper describes the derivation process of steel anvil mass. Based on the law of momentum conservation and through the analysis and calculation of impact dynamics in the process of impact check of rebound test hammer, the source of technical index of check steel anvil used in spring test hammer is pointed out, and the scientific traceability is verified theoretically and in practice, which...
Developments in reference standards in Hardness Laboratory of TÜBİTAK UME (National Metrology Institute of Turkey) and the demand received from calibration and testing laboratories forced us to develop a new hardness indentation measurement system (HIMS) that covers all Brinell, Vickers and Knoop hardness indentation measurements. In this design it has been aimed at automatization of...
This paper investigates different possibilities of measurement and control of pressure in the cryostat filled with liquid nitrogen. Design of novel membrane pressure regulator for automatic control of pressure in the range from 1 to 3 bar gauge in the cryostat is presented. The performance of the regulator is evaluated through measurement of pressure deviations from set-point value and their...
This paper reports the design of a linear-motion type microforce generating machine by applying the principle of Kibble balance. A novel schematic diagram of the machine is proposed. “Microforce” in the order of micronewton to millinewton can precisely be generated by this newly designed machine. It is expected to contribute to improving the reliability of microforce measurement.
This paper describes a new type of Buchholz Indentation Hardness Tester used in Buchholz Indentation test for paint and varnishes. This new type tester uses a bridge structure to connect two cantilever sensors together, so we can instantly know the magnitude of the acting load on paint and varnishes. The design overcomes the defects of the previous load changes that could not be accurately...
In the field of hardness measurements, a problem arises when trying to understand how different measurement parameters (speed of the indenter, force, thermal drift, etc.) affect the outcome of the measurement itself. Because the mathematical model defining hardness scales do not consider such factors, the simplest way to include additional influence parameters in the mathematical model is to...
In high-resolution investigations of bridge amplifiers with the aid of cascaded inductive voltage dividers, a fine sawtooth structure was recently detected at PTB in the characteristic curves of certain amplifier types. These results could now be confirmed with simple mechanical means. The easy availability of the presented method opens the possibility for many laboratories to estimate the...
Abstract:
The deadweight torque standard machine has the characteristics of less uncertainty and good stability. 100 kN•m torque standard machine adopts the moment arm-deadweight type. The main knife assembly is adopted to support the moment arm which has low friction under high bearing capacity, the moment arm system is precisely machined and adjusted to ensure parallelism between main knife...
Dissimilar approaches to bench-top Kibble balances are available worldwide. However, so far, the literature has not disclosed a Kibble balance aimed to measure ultrasonic radiation force (URF). Due to the nature of Kibble balances, it could be useful and even more valuable to assess URF. This paper describes the development of a bench-top Kibble balance to measure URF. The system was compared...
This paper presents the main results and achievements of the EMPIR DynPT project [1]. Dynamic measurement of pressure and temperature are a key requirement for process control in several demanding applications, such as automotive, marine and turbine engines, manufacturing processes, and ammunition and product safety. The quality of these measurement has been significantly improved in this...
This paper focuses on the process of establishing a national standard in the Laboratory for Pressure at the Montenegrin Bureau of Metrology (MBM), the National Metrology Institute of Montenegro, which disseminates the pressure unit in the field of calibration and conformity assessment in a small, centralized metrology system. Establishment of traceability chain, development of measurement...
This manuscript introduces the development concept of a reliability evaluation device for vibration sensors in a real environment. The reliability evaluation device consists of a low-frequency triaxial vibration exciter and a testing bath capable of controlling temperature and humidity.
Industry 4.0 [1] revolution provides new opportunities in the arena of manufacturing and metrology. To take advantage of this opportunity, EMRP 18SIB08 ComTraForce project has started to develop digital constructs necessary for a Digital Twin of a load cell that allows, in real time, to predict, optimise and maintain desired functionality throughout the device lifetime. Specifically, we have...
Load cells, like any other measuring device, are vital in ensuring that products meet quality and safety requirements; therefore, they must always be accurate and reliable. Creep is affecting measurement results and the useful life of load cells but is not well understood. Digital twins create a virtual representation of an instrument that can be used to understand, monitor, and predict load...
The SI unit of mass, the kilogram, was redefined on the 20th of May 2019. The new definition is defined in terms of the fixed numerical value of the Planck constant, h. The kilogram no longer takes traceability from IPK and therefore a new system of traceability and dissemination must now be established to ensure reliable and repeatable measurements for industry. Two methods of dissemination...
On 20 May 2019 a new definition of the SI unit of mass, the kilogram, came into force. The kilogram is now defined based on a fixed numerical value of the Planck constant. This leads to a new situation for mass metrology that in principle every National Metrology Institute can realize the kilogram. To ensure global uniformity, the Consultative Committee for Mass and Related Quantities (CCM)...
This paper studies the possibilities of increasing the amplitude range of the generated pressure steps in the developed diaphragmless shock tube by using appropriate combination of gases in the driver and driven sections of the shock tube. The measurement results of the generated pressure steps using lower-molecular-weight driver gases and higher-molecular-weight driven gases will be presented...
This paper compares static and continuous performance characteristics of a force transducer, determining the effect of force application rate, force application principle, and filter settings on the observed differences. It also develops a methodology for identifying and correcting possible non-synchronisation between instrument channels.
In this paper, the effects of stress-strain data synchronization errors on Young’s modulus of hard and soft materials in typical material testing machines are described. Seven materials, three Cu-Cr-Zr alloys and four polymers, are tested in two machines conceived for the measurement of the mechanical properties of hard and soft materials. In both machines, the synchronization of stress and...
Abstract:
Torque measurements with influences of temperature and rotational speed are vital performances for measuring the efficiency of rotating electrical machines on test benches. During the experimental efficiency measurements, the influences of temperature and rotational speed generate errors on the torque measurements, and hence the overall traceable efficiency measurement on test...
This contribution proposes a methodology to predict the transfer function of an accelerometer solely based on an electrical impedance measurement. Such impedance measurement can be conducted in-situ and has certain advantages for some types of accelerometer and under certain measuring conditions. A proof of concept study has been conducted where the methodology is used to estimated the...
In mass measurements of weights in the air, its density or volume must be known to correct for the buoyancy effect. Recently, formulae for an improved volume determination of OIML R111 weights with geometric measurements have been developed. However, the experimental measurements required to use the enhanced mathematical model are still under improvement. This paper shows the results of...
In static force and torque calibrations, the quantity is applied to the given measuring instrument in discrete steps to form a measurement series that usually consists of five to ten values. The corresponding calibration results and uncertainties are then acquired through calculation. During normal use of the instrument, the values measured are often distributed within a range and do not align...
This paper describes the method to characterize the zero-pressure effective area (A0) and pressure distortion coefficient (lamda) of 200 MPa-CCPG oil piston-cylinder unit (PCU) in order to realize the national pressure scale from 1.5 kPa to 500 MPa. A0 was determined by cross-floating method from a group of primary gas pressure standard, while the H-W method was used for calculating the lamda....
This study includes measurements carried out according to ASTM E467 international standard by using different loading rates also force waveform sine, in order to comprehensively investigate dynamic verification in force sensors which have two different measuring principles. It has been aimed to reveal and evaluate the effect of dynamic verification on different types of force...
This paper describes the uncertainty evaluation of calibration results of vibration transmitter. Under the proper vibration amplitude, the vibration transmitter outputs voltage or current proportionately when they all have a certain degree of accuracy or uncertainty. So the measurement of current or voltage becomes the key parameter of uncertainty evaluation. The evaluation of uncertainty is...
The expansion of the high-technology leads to the increasing demands for the calibration services in the extremal pressure ranges, both vacuum and high gauge pressure in liquid medium. The presentation will deal with the second one, focusing on the solution chosen by the Czech Metrology Institute (CMI) to improve its services in the range of gauge pressure from 0.5 GPa to 1 GPa. A new...
The feed drive system for machine tool consists of rolling elements such as ball screw and linear guideways. It is well known that in the positioning of linear guideways using steel ball rolling, the contact surface has nonlinear spring characteristics. This phenomenon is deteriorating the accuracy of the machine tool. In this study, we have manufactured a feed drive system in which the...
The effect of the piston rotation rate on the gauge pressure measured by deadweight pressure balances was experimentally studied. Experiments were performed with a PTB twin primary gas pressure balance and several commercial gas and oil operated pressure balances with different configurations and size of rotating weights. It was found out that the piston rotation effect significantly depends...
In the last years, there have been a continuous development in traceability in measurements of dynamic properties in mechanical quantities. There has been big progress in reference systems for pressure as well as ongoing work in force and torque as well. So far, the work has been focused on realization of primary systems but soon the area will be mature enough for international acceptance of...
This paper describes the final design of the worldwide first 5 MN∙m torque standard machine developed by PTB with the possibility of a future extension to 20 MN∙m.
This work is dedicated to the demonstration of a dynamic force measurement system for precise characterization of the force transducers. The rocking motion of the system as a main dominant source of uncertainty in the acceleration is investigated. We propose a novel method based on the application of an artificial neural network for evaluation of the data as an alternative to traditional...
IMEKO 24th TC3, 14th TC5, 6th TC16 and 5th TC22 International Conference
11 – 13 October 2022, Cavtat-Dubrovnik, Croatia
FORCE AND TORQUE MEASUREMENT DEVICES – CALIBRATION AND INTERPOLATION
Boris Katz/Presenter1, Guy Katz2
1 Metrology Consulting, Netanya, Israel, boriskatz123@gmail.com
2GK Calibration, Netanya, Israel, gkatz1@gmail.com
Abstract:
Concentrated and specified...
This paper describes the new proposal of the calibration of hydraulic torque wrenches. The calibration includes the different metrological effects of the hydraulic torque wrenches like repeatability, reproducibility, and the piston position. A sensitivity analysis is introduced to the different uncertainty contributions of the of hydraulic torque wrenches like the piston position, mounting...
The paper presents recent developments related to the establishment of a calibration procedure for automatic catchweighing instruments (catchweighers). The main purpose of the proposed calibration method is to provide a basis for traceable measurements of catchweighers in the dynamic mode of operation outside of the control of legal metrology. The specifics of the instruments’ operation in the...
At PTB, an interferometric liquid column manometer for the pressure measurement up to 2 kPa is under development. Its in-situ liquid density measurement is a new approach for those primary pressure standards and makes the use of low-density liquids, low in comparison with the density of mercury, a liquid often used in other standards, possible. Such liquids, here, vacuum oils, offer an...
Static calibration of uniaxial force transducers is performed with force standard machines which generate a pure downward vertical force. However, these machines can be subjected to parasitic components which are transferred to the transducer under calibration. These components affect the calibration results, therefore they should be estimated and the sensitivity of the instrument to such...
Improvements in quality assurance in the field of hardness testing and demand received from calibration and testing laboratories as well as hardness testing machine producers and other users made it inevitable to develop a High Load Brinell Hardness Standard Machine (HLBHSM) at Hardness Laboratory of TÜBİTAK UME (National Metrology Institute of Turkey). Design of such a national standard was...
After successful implementation of two hardness standardizing machines at TSE (Turkish Standards Institution) in Rockwell and Brinell-Vickers hardness scales separately, it is aimed to combine them in a newer design and install in Hardness Laboratory of TÜBİTAK UME (National Metrology Institute of Turkey). Design of such a national standard was made for Rockwell, Brinell and Vickers hardness...
The studies of instrumented indentation test at elevated temperature have been increasing in recent years. However, there are few studies about the validity of instrumented indentation test at elevated temperature. For investigating the validation of instrumented indentation test at elevated temperature, we compared the results from the instrumented indentation test with those from...
An interlaboratory comparison between TÜBİTAK UME (National Metrology Institute of Turkey) and TSE (Turkish Standards Institution) was organized in the field of Hardness Metrology to determine the consistency of the primary hardness standard machine of TÜBİTAK UME and hardness calibration machine of TSE realizing Rockwell Hardness measurements in accordance with ISO 6508-1:2016 and ISO...
A reference type torque calibration machine (RTCM) has been developed to improve the efficiency of calibration service for torque measuring devices at the National Metrology Institute of Japan (NMIJ), part of the National Institute of Advanced Industrial Science and Technology (AIST). The nominal capacity of the RTCM is 10 N·m. In this study, we evaluated the calibration and measurement...
The paper describes the difference in the standards of measurement for weighing indicator. A digital load cell simulator with high resolution for type evaluation of weighing indicator was developed and its traceable calibration was also presented. The type evaluation method of weighing indicator was investigated and the performance test effect on the indication error was also discussed.
Due to that displacement and absorbed energy are calculated by obtained force data, the force measuring chain’s dynamics fatally affects test result in instrumented Charpy impact test. Hence it is essential to evaluate the force measuring chain’s dynamics. During the impact, the specimen can vibrate at the frequency from 300Hz level to 15kHz level. This research provides two methods for...
In this study, the effects of the waiting time in the force steps on the calibration results during the calibration of force measuring devices was investigated. For measurements, strain gauge force measuring device and piezoelectric force measuring device were selected. Both force transducers are calibrated to the ISO 376 standard. The waiting times in force steps during calibration were taken...
The redefinition of the kilogram in 2019 in terms of a fixed numerical value of a constant of nature, the Planck constant h, created the opportunity for the realisation of mass at any point on the scale and improvement in the uncertainty at sub-gram scales. In this work, part of the route to measurement of mass at small scales at the National Physical Laboratory (NPL) will be described. The...
We present in this paper the development of an innovative technique for the measurement of acoustic pressures in the range of 40 mHz up to 20 Hz. This new measurement technique is based on the use of a Fabry Perot (FP) refractometer in which the air density variations related to an acoustic wave can be tracked and determined by measuring the variations of the optical frequency of a laser...
The multi-component vibration calibration device at PTB consists of a 3-axial shaker which is suitable and convenient for calibrating multi-axial seismometers, and three laser vibrometers are utilized as reference. For a European research project, the frequency range was further extended. Instead of a closed-loop control system limiting the vibration frequency down to 0.4 Hz, now a signal...
A hinge measurement flexure calibration set-up for stiffness measurement is built at Physikalisch-Technische Bundesanstalt (PTB) to estimate parasitic load at the new 5 MN·m torque standard machine. This paper describes the improvements on the measurement flexure calibration set-up that have been made since its first presentation. The list of measurement uncertainty influences is refined....
Rocking motion is often a significant source of uncertainty in sinusoidal calibrations of accelerometers and force transducers. We describe real-time measurements of rocking during sinusoidal excitation, performed at NIST. The measurement is contactless and can be performed simultaneously with the motion. We report rocking measurements for excitation frequencies up to 2 kHz. The results...
Generally, there are three primary methods in vacuum metrology: mercury manometer, static expansion method, and continuous expansion method. An important parameter that needs to be taken care of in primary vacuum calibration methods is the compressibility factor of the working gas. In this paper we will present the measured data for virial coefficients of three gases Helium, Argon and Nitrogen...
The Planck-Balance 1 (PB1) is a compact Kibble balance with the aim to calibrate weights of high quality. In contrast to most other Kibble balances PB1 employs a sinusoidal trajectory in the velocity mode, rather than a linear one. Thus, the induced voltage is an AC signal of 4 Hz. At PTB we implemented a commercial AC Quantum voltmeter in order to ensure traceability to highest level. Here,...
The most important uncertainty component of the pressure step signal determined at the end-wall of the shock tube is associated with the uncertainties of the shock wave velocity and the arrival time of the shock front. The latter is determined using a time-of-flight method and is therefore greatly affected by the errors in the detected times of the shock wave passages over the side-wall...
In several applications, such as industrial plants monitoring, or peculiar manufacturing process, the sensors are subjected to a wide range of acceleration amplitude levels or shocks, as well as thermal changes, that could affect the micro electro-mechanical inner parts, altering their performance and reliability. In this work, by applying a calibration procedure developed at INRIM, the main...
The article describes metrological studies of the Russian national primary standard machine on Brinell hardness scales. The factors influencing the uncertainty of the hardness numbers on the Brinell scales are estimated.
Small motors are used in aviation, aerospace and other industrial systems widely. However, the dynamic and changed small torque of these small motors cannot be measured and calibrated automatically and timely. This paper developed a torque Calibration and Measuring Device with Elastic suspension based on the electromagnetic force balance technology and elastic suspension support technology....
This paper explores the use of fitted sensitivity values in order to minimize the effects of spurious resonances in the frequency response of reference accelerometers used in secondary vibration calibration.
Subdivision is a crucial technique in mass metrology because it allows the determination of the mass of weights of various nominal values and the realisation of the mass scale.
This technique is usually based on complicated mathematics. The current models are generally sufficient for many practical aims but far from the best performance.
Project 19RPT02, “Improvement of the realisation of...
This paper describes modernisation of a vacuum calibration system in VTT Technical Research Centre of Finland Ltd, Centre for Metrology MIKES (VTT MIKES). VTT MIKES is performing vacuum calibrations by direct comparison with reference gauges. The vacuum calibration system is modernised by replacing old manual valves with digital, computer hosted control valves to enable automated calibration...
The gravimetric method for standard leak calibration is already documented and has proven to be repeatable. However neglecting the air buoyancy correction in some cases may lead to a significant increase of the uncertainty and a bias on the result. The aim of this work is to provide a method for atmospheric leaks calibration using simple mass comparisons and the Monte-Carlo method in order to...
This article describes the behavior of setting torque screwdrivers. In contrast to setting torque wrenches, such screwdrivers have multiple setpoints that can be quite different. This fact has a crucial impact on their calibration. The article focusses on the determination of the setpoints as well as on the rise and fall times of the torque. Initial measurements are also presented.
Adaptive Monte Carlo procedure given in Supplement 1 to the “Guide to the expression of uncertainty in measurement”(GUM S1) and modified GUM S1 procedure were applied to reach a prescribed numerical accuracy of the Monte Carlo results for a chosen confidence level. We assess the performance of the adaptive procedures by employing the measurement model that defines differential pressure...
This paper describes practicalities of pressure balance piston-cylinder cleaning. A special case covered is the cleaning of Force-balanced Piston Gauge (FPG) piston-cylinder unit. A basic cleaning procedure is presented in the official manufacturers manual, but every now and then there is no success in the cleaning results despite the fact everything is performed according to instructions....
Dear Sir,
Rate accuracy and stability tests for turn tables are performed and the analysis results will be evaluated. Also, measurement uncertainty will be calculated for rate measurements.
Precise knowledge of cylinder pressure is needed for optimizing engine performance. To ensure reliability of measurements, pressure sensors need to be calibrated at conditions that correspond to actual use, i.e., at dynamic conditions and elevated temperatures. VTT has developed a dynamic pressure calibrator based on reference sensor principle to enable cost-effective dynamic calibrations up...
Primary calibration of accelerometers by laser interferometry has been performed for more than 50 years. It was made possible by the advent of the commercial He-Ne lasers in the 1960ties. During the last 20 years the progress in digital signal treatment has made it available for most interested laboratories.
However, these huge progresses have merely reduced but not removed some basic...
The Czech Metrology Institute (CMI) decided to build a new orifice-flow-apparatus for the border of fine and high vacuum utilizing two different orifices exchangeable under vacuum. However, one of the originally created orifices had unsatisfactory parameters. The presentation will describe choice and parameters of a replacement and the main final characteristics of the system.
According to the test methods and requirements of the weighing temperature test, this paper analyzes the technical problems currently faced by the temperature test of large weighing instruments, and develops a device and method for temperature test of large weighing instruments were carried out to ensure that when the temperature changes, the weighing instruments can still maintain its...
OIML R76 is a recommendation file of non-automatic weighing instruments (NAWI), which is widely accepted in country members. As an instrument for trade using, NAWI is known intimately and easy to judge weighing correct.
In OIML R76, there are E0, E and Ec, usually Ec is as the final error compared with maximum permitted error, Ec= E- E0, which are complex concepts; but in fundamental ideas,...
In order to demonstrate the importance of the effect of reasonable speed bump on dynamic weighing results. This paper establishes the kinetic model model of automobiles and deceleration belts, and performs simulation analysis and test verification. The experimental results show that when the normal speed of the three-axis car is cross the speed of speed, the distance between the deceleration...
This paper describes a set of intelligent detection system for large mass weights. The system realizes the intelligent operation of the process of (100kg ~ 1000kg) mass weight verification, including loading and unloading standard weights, loading and unloading tested weights, loading and unloading counterweight weights, data processing, issuing verification records.These intelligent...
Young's modulus is an important mechanical parameter to describe the resistance of solid materials to elastic deformation. It is one of the important basis for selecting mechanical component materials in engineering design. Its accurate measurement is of great significance in scientific research and technical application.
In engineering technology and experimental teaching, the static tensile...
Quantum-based methods have the potential to become primary standards for the SI unit of pressure, the pascal. Some of these standards are based on the Determination of the refractive index of a gas under different pressure conditions by FP-based refractrometry methods. These methods depend on the control of other quantities, mainly the temperature and the mechanical stability. Ideally, the use...
This paper introduces common abnormal pass behaviour of automatic instruments for weighing road vehicles in motion(WIM) and gives the corresponding test method. Common abnormal behavior of WIM include “S-line” driving, static and dynamic driving, line pressing driving, cross road driving, etc .
Based on the characteristics of automatic intelligent detection device and the demand of high-accuracy group weights value transmission, this paper proposes two measurement design methods for combined verification of class E group weight, establishes the mathematical model and analyzes the uncertainty. The two combination methods are compared with the one to five component combination method...
Abstract:
The precise measurement of weight volume is an important part of mass measurement. A novel set of apparatus combined with automatic measuring devices and weighing instrument for weight volume measurement has been developed successfully. This paper introduce the device and the measurement experiment.
Keywords: weight standard; hydrostatic; volume; mass calibration
This paper describes two ISO 7500-1 round robin tests in Germany, which were undertaken as a tool to meet the requirement of ISO/IEC 17025:2017 for interlaboratory comparisons. Up to 40 accredited laboratories calibrated the force measuring devices of different material testing machines at the IfEP, the Institute for Proficiency Tests. The method, uncertainty calculation and results of the...
Abstract:
This paper describes geometric design consideration for the creation (manufacture) of a tri-axial accelerometer intended for the validation of multi axis calibration systems that implements simultaneous axis calibration methods. Two mounting geometries are investigated, and the results obtained using them are reported. The one configuration, a cube with counterweights. The second...
A half-sine generator is preferable as a standard to calibrate the dynamic pressure sensors having an advantage of a short exposure time on a possible large momentum during calibration. A compact impulse dynamic pressure standard has been developed. This system used a horizontal shock force generator adopted from the sock acceleration exciter instead of using a drop-weight with a limited...
This paper focuses on behavior of a dynamic mass measurement system. The goal of this paper is to propose a simple dynamic model of the system, which can reproduce dynamic behavior to floor vibration. The dynamics of our system with electro-magnetic force compensation is approximated by a mass-spring-damper system, and an equation of motion is derived. Model parameters are also estimated from...
Sinusoidal torque calibration system based on rotating table and interferometric system is developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses servomotor to generate dynamic torque in the torque range from 0.1Nm to 200Nm at frequency from 1Hz to 200Hz. Heterodyne laser interferometers cooperated with column grating are used for angular acceleration measurement. This...
Load cells are usually applied in industry where
high quality materials and reliability in a wide range
of environments are paramount. Differences exist in
performances, accuracy, fabrication technologies,
intended application, and cost; notwithstanding this,
repeatability, hysteresis, creep and dynamic
response can be a prevalent cause of errors in
standard strain gauge...
This paper described the study on the tacho-torque measurement’s dynamical calibration. Two sets of standard devices were designed and developed to cover the small measurement range and big measurement range. Thus, the online and dynamic calibration on tacho-torque is realized. Meanwhile, the different design philosophy of calibration devices is also compared and discussed.
This paper tried the method of directly calibrating and verifying the reference torque wrench on the deadweight torque standard machine. Specially tool and grips are designed, the arm length can be adjusted, and the installation position can be changed according to needs, which fully meets the requirements of German DKD-R3-7 and Chinese verification regulations JJG1103-2014. The differences...
The torsional vibration calibration method with the eccentric shaft is studied in this paper. The standard torsional vibration can be obtained by the eccentric shaft at the both ends of the torsional spring, while two servo motors are employed respectively as the driving motor and the loading motor. Both the simulation and the test data illustrates that up to 10° torsional angle amplitude can...
High-sensitive accelerometers are used in microvibration measurement for stabilizing satellites and machinery monitoring. We achieved calibration of such high-sensitive (2 V/(m/s2)) accelerometer up to 6.3 kHz using 0.1-m/s2 vibration, which corresponds to sub-nanometer displacement amplitude.
The surface tension of 7 test liquids, used as density reference liquids in the EURAMET Project 17RPT02-rhoLiq, was determined at 20 C, by 3 National Metrology Institutes (from Poland, Portugal, and Turkey), by means of force tensiometers, with different Pt measuring probes (Du Noüy ring and Wilhelmy plate), and by applying different correction factors. The results of this paper will allow to...
This paper provides an overview of the architecture of the NPL Next Generation Kibble Balance. The balance is intended to realize SI mass in the 100-250 g range with an ultimate target uncertainty of 1-2 parts in $10^8$. It is intended to be simpler to build and operate than previous generations of Kibble balance with the aim of allowing many more laboratories to participate in the realization...
This paper describes the design and construction of the hydraulic amplification force standard machine of 30MN, which will be the biggest force standard machine by hydraulic amplification in the world. There is new technology like static pressure, suspending and so on used in this machine. Meanwhile the whole construction of machine and main parts e.g., deadweights group also be described and explained
Based on the “force standard machine weight exchange method and weight exchange device” patent technology，a deadweight force standard machine（DWM）of 500kN was developed. Benefited by the weights exchange control system with 8 weights and load frame，this machine can load/unload any load-level equally with the minimum increment of 10kN，in 10kN-500kN range，and the load history curve is basically...
A pressure balance is a primary system for the application of a vertical load on a piston to generate a reference pressure. There are various parameters to calculate reference pressure on pressure balances, such as piston’s area, linear deformation of piston and cylinder, measuring temperature, mass weights, local gravity, surface tension of measuring liquid… In this study, the effect of...
The alignment measurements of material testing machines can be made according to ASTM E1012 and ISO 23788 standards. These standards provide information on alignment devices, alignment measurement, and post-measurement calculations. However, they can't make a definition for the calibration of the alignment measuring device. For this purpose, this article has been prepared as a recommendation...
Our primary goal is to establish an optical pressure standard based on the Optical Interferometer Manometer (OIM) at the CSIR, National Physical Laboratory (NPL), New Delhi, India. Starting with known pressure levels, theoretically, we may calculate the refractivity of the Helium gas. This would be done for a set temperature of 300 K and two wavelengths of laser light at 633 and 1542 nm...
An Invar-based dual Fabry-Pérot cavity instrumentation used for assessments of refractivity and pressure by the gas modulation refractometry (GAMOR) methodology has been scrutinized by both simulations and experiments with respect to the thermodynamic effects (pV-work) that originate from the gas exchange process. It was found that all temperature gradients in the system are well into the...
Calibration of broadband seismometer following ISO 16063-11 down to 8 mHz is required for the traceability. However, calibration result is seriously affected by the gravitational acceleration coupling through the tilt of the vibration exciter below 0.1 Hz. In this work, calibration with the tilt coupling correction was performed down to 5 mHz.
Time Constant represents the main dynamic performance of sensors to measure varying torque, and its calibration attracts increasingly more attentions in practical engineering applications. The time constant calibration of torque sensors is studied based on negative step method in the paper. The fall time of the negative step torque is validated to be lower than 0.1ms through experiment...
This paper presents the results of a bilateral comparison in torque measurements between NMISA and INMETRO in Brazil. For this comparison, NMISA used a 20 kN·m torque comparator machine with a proposed uncertainty of 0.03% across the entire measuring range. INMETRO used a 3 kN·m lever deadweight standard machine with uncertainty of 0.01%. The comparison was conducted for both clockwise and...
The traditional torque calibration is carried out under laboratory conditions, which can not accurately reflect the operation status of the equipment in the external harsh environment. Firstly, this paper analyzes the design scheme of high and low temperature environment（-50℃～100℃），studies the feasibility of temperature control system. Secondly, the 5kN·m torque calibration connection...
This paper describes the dynamic calibration of material testing machines with a force transfer standard traceable to national standards.
In nacelle system test benches, different wind
profiles are simulated by applying different torque
loads and rotational speeds amongst other things.
Unlike load sequences during calibration
measurements, these profiles are neither constant
nor increasing and decreasing through controlled
steps. This article proposes a sequence of partial
range and...
The build-up force standard machine is usually calibrated by using the high precision force transfer standard, which calibrated by the force standard machine with high accuracy. The response of the build-up machine is generally considered as a linear system. It is characterized by a liner function based on the calibration results. The accuracy of the slope in the linear function will be...
This paper describes Build-up force standard machine (BM) influence factors and uncertainty contributions resulting from reference force transducer, mechanical system and control system. Because of these influences, multi-working conditions is a BM’s significant feature, and it is difficult to evaluate a BM’s uncertainty only using data under a certain condition. As a kind of force standard...
In this study, the uncertainty in the dynamic torque realized by a dynamic torque generating machine (DTGM) based on an electromagnetic force under development at NMIJ was evaluated. In this machine, dynamic torque can be generated by changing the applied current, and the generated torque can be traceable to the International System of Units (SI) by referring to the national standards of...
Hardness reference blocks play a pivotal role in ensuring traceability of hardness measurements. However, it is challenging to calibrate them in accordance with part three of the ISO 6508 without performing time-consuming pre-measurements. A new method developed by the PTB automates the test cycle and eliminates the requirement for pre-measurements. This is done by estimating the hardness...
We have proven that commonly available SFP modules can be used for LDV stimulation. While the expected intensity modulation at the photo diode inside the LDV interferometer is more of a sine shape and the SFP module output is designed for and provides a rectangular AM modulation, the vibrometers tested show a comparable result.
This is a new setup constructed in our department in order to measure the helium permeation in zerodur
Low uncertainty Kibble balance measurements require careful consideration of the effect of external sources of vibration. This paper compares vibrational modelling of the machine frame of the National Physical Laboratory’s next generation Kibble balance using three different software packages. The output of the modelling was compared with physical measurements on the machine frame using a...
