Deadweight Force Research Articles

Optimal Combination Method for Weights Loading of the Deadweight Force Standard Machine

Optimal Combination Method for Weights Loading of the Deadweight Force Standard Machine

Evaluation of small-capacity force transducers using a developed 2 N dead-weight type force standard machine

A 2 N dead-weight type force standard machine (DWM) had been developed at the National Metrology Institute of Japan (NMIJ). Modifications of the force transducers and weight receivers of the DWM improved measurement reproducibility with rotational position change. Two modified small-capacity force transducers with rated capacities of 1 and 2 N could be precisely calibrated according to International Organization for Standardization (ISO) 376. The results showed quite smaller uncertainties in the calibration ranges of 100 mN to 1 N and 200 mN to 2 N than the catalogue accuracies of commercial transducers. The validity of the calibration capability of the 2 N DWM was confirmed by comparing it with a 50 N DWM. The results obtained by two DWMs coincided within the uncertainties of calibration.

Design and development of high load Brinell hardness standard machine at UME

After successful implementation of two hardness standardizing machines at TSE (Turkish Standards Institution) in Rockwell and Brinell-Vickers hardness scales separately and deciding to combine them in one machine with a newer design and install it in Hardness Laboratory of UME (National Metrology Institute of Republic of Turkey) it was planned to design and develop a deadweight type Brinell Hardness standard machine at UME for high load scales within the scope of an internally funded project. In this paper the design of High Load Brinell Hardness Standard Machine with dead weight force application system realized by UME Hardness Laboratory is explained.

NMISA’s new 5 kN deadweight force standard machine

This paper describes NMISA’s new 5 kN deadweight force standard machine. The machine has the capability to generate force in the range 50 N to 5 kN. The machine uncertainty is conservatively estimated at 0.008 % across the entire measuring range. The weights are adjusted according to the gravity value measured in the laboratory. This machine is used for the calibration of force transducers in tension and compression.

Self-calibration of the 1 MN deadweight force standard machine at INRiM

The INRiM 1 MN deadweight force standard machine (DFSM) was installed in 1995. It adopts a binary sequence of ten weights whose combinations generate forces up to 1 MN. The advantage of this system lies in the self-calibration of its weights. The procedure is based on the comparison between two forces generated by a single weight and by a group of smaller weights, nominally equal. After 25 years, a verification of the DFSM was performed. Results are within the declared CMC limits, i.e. a relative expanded uncertainty of 2 × 10<sup>-5</sup>.

Analysis of mechanical properties for the key force transfer components of 2 MN deadweight force standard machine

The good mechanical properties of deadweight force standard machine (DWM) are the basis to ensure the accuracy of its measurement. Aiming at the development of 2 MN DWM, this paper carries out simulation analysis on the key components of the force value transfer process. The analysis results provide constructive suggestions for the development of 2 MN DWM.

Intercomparison between deadweight machines in China and UK up to 1 MN

This paper describes a tripartite comparison at forces of 250 kN, 500 kN, and 1 MN between deadweight force standard machines located at FJIM (China), NIMTT (China), and NPL (UK). Two different transfer standards were used, and the results demonstrated good agreement between the three machines, with <em>E</em><sub>n</sub> values of significantly lower magnitude than one.

A new design of Rockwell-Brinell-Vickers hardness standard machine at UME

After successful implementation of two hardness standardizing machines at TSE (Turkish Standards Institution) in Rockwell and Brinell-Vickers hardness scales separately, it became unavoidable to combine them in one machine with a newer design and install it in Hardness Laboratory of UME (National Metrology Institute of Republic of Turkey) within the scope of an internally funded project. In this paper the new design of the Rockwell-Brinell- Vickers hardness standard machine with deadweight force application principle and a laser interferometer optic system as depth measurement unit for Rockwell Hardness scales designed by UME Hardness Laboratory is explained.

Research on the swing and vibration restraint of the 2 MN deadweight machine frame

In this paper, the new 2 MN deadweight force standard machine of FJIM (Fujian Metrology Institute) with an optimal 20 kN frame with swing and vibration restraint is detailed. Load transient response is considered in the design of column, and a mass damper is used to make the frame stable in 3 s. These methods help the machine reach the uncertainty it claimed.

STANDARDS IN FORCE MEASUREMENTS

Force measurement is an important aspect in testing and determining the characteristics of units, machine parts and materials, building materials and structures, the quality of metallurgical products, as well as when assessing the conformity of force and weight transducers. The purpose of this study is to select the optimal procedure and methodology for realization, storage and transferring of the unit size of force in the country, as well as to ensure its traceability to the international system of SI units. This paper analyzes existing methods of realization, storage and transferring of unit size, such as deadweight force standard machines, hydraulic amplification force standard machines, lever amplification force standard machines and systems (groups) of several force transducers (BU system) that can be used as reference by metrological institutes and calibration laboratories. The main principles of operation of the above mentioned machines of realization of a unit of force are considered, including the components of measurement uncertainty and the nature of their origin with the possibility of further consideration in the uncertainty budget. The calibration and measurement capabilities of the world's leading metrological institutions, which maintain different classes of force standard machines for reproducing the size of a unit of force, namely the measurement range, measurement uncertainty, as well as overall dimensions, operating features, etc. are analyzed. The results of the analysis of the disadvantages and advantages of the three main classes of force standard machines for reproducing the size of a unit of force are presented in this article. Conclusions are made on the creation of a national standard of the force unit based on the installation of lever amplification force standard machines, which are based on the analysis of methods of reproduction and transfer of the size of a unit of force, which will occupy positions among the world's leading metrological institutions.

Evaluation of newly developed 50 N dead-weight type force standard machine using tuning-fork type force transducer

A 50 N dead-weight type force standard machine (DWM) was developed by the National Metrology Institute of Japan to expand the lower end of calibration force from 10 N to 1 N. The weights of the DWM consisted of a loading frame and a linkage-weight stack. The loading frame applied a gravitational force of 1 N to a force transducer under calibration. The calibration and measurement capability of the 50 N DWM was verified to be 2 × 10−5 relative using a tuning-fork type force transducer in accordance with ISO 376. The equivalence between the 50 N and 500 N DWMs was confirmed by performing an intralaboratory comparison using the tuning-fork type force transducer. Moreover, the competence of the transducer for the evaluation of DWMs was demonstrated.

Flexural buckling of a revolving bar in a rigid pipe with a gap exposed to axial force and dead weight

The article proposes a solution to the stability problem of a revolving bar loaded with axial force and inserted into a rigid pipe with a gap by the Bubnov-Galerkin method. Two options as the deflection coordinate functions are considered. When calculating, the dead weight of the bar is taken into account. With a total load greater than the Euler load, lateral forces (reactions), touching the pipe wall, appear in the bar. At the end of the article, the formulas for determining the voltage after buckling are presented. The obtained formulas make it possible to determine the critical load of the system for each individual case, taking into account its dead weight and centrifugal forces from the revolving bar. The above-mentioned relations also give an opportunity to determine the reactive moment magnitude from the contact of the revolving bar and the pipe wall.

Development of 2 N dead-weight type force standard machine

A 2 N dead-weight type force standard machine (2 N DWM) equipped with a balancing mechanism to cancel out the gravitational force acting on the loading frame is developed by National Metrology Institute of Japan (NMIJ), AIST. Removable standard weights are selected in accordance with the calibration force steps and placed onto a weight-loading mechanism. The minimum force that can be realized is 10 mN. The relative expanded uncertainties of the realized forces with coverage factor k = 2 are evaluated as 5.8 × 10−4 and 2.9 × 10−5 at force steps of 10 mN and 200 mN, respectively. Repeatability is evaluated in the range of 100 mN–2 N with the use of a 2 N force transducer. With the development of this standard machine, the force standards disseminated from NMIJ extend down to 10 mN. We believe that our work can further contribute to developments in force standards.

Optimal shells of revolution and main optimizations

Introduction. Optimization is a criterion, on the ground of which, comparative estimation of possible alternatives and selection of the best decisions is carried out. Cost of a shell, its minimum weight, absence of bending moments and tensile normal stresses, given stress state for acting external load, given bearing capacity when optimal shallowness, maximum external load, minimum weight under limitation on the value of natural frequencies of vibration and maximum displacements, absence of bending moments with taking into account internal pressure, dead weight, and centrifugal forces; maximum of critical force and something else can be criterion of selection of optimal shape of shell of revolution. Methods. The main criteria of optimality for shells of revolution and information sources for the 1970-2019 periods are presented in a paper. It will help to study previous results devoted to using optimizations and to set about further investigation. But there is no single approach to the definition of optimal shell of revolution and obviously will not be, because own optimizations are necessary for every concrete case of loading, or distribution of stresses along the thickness, or under the demands to the ratio of the volume and area of considered shell, or with due regard for different kind of expenses, and other demands. Results. For the first time, 24 criteria of optimality only for shells of revolution were discovered. The names of scientists offered presented criteria of optimality and the 45 references dealing with this question are pointed out. It is shown that principles put in the basis of optimal design and criteria of optimality must be given with the help of language quite naturally for computer. Having used optimi- For citation Krivoshapko S.N. (2019). Optimal shells of revolution and main optimizations. Structural Mechanics of Engineering Constructions and Buildings, 15 (3), 201-209. http://dx.doi.org/ 10.22363/1815-5235-2019-15-3-201-209 zations presented in the paper, designers can choose the criterion for their own design of optimal shell shape. Study of the prerequisites of the structural solutions in building and machine-building, the history of the development and perfecting of technologies of erection of shells of revolution will permit to generalize the experience accumulated by designers and to develop new fundamental solutions. Otherwise, architects, structural engineers, and designers will be repeating the achieved solutions in building, architecture, and machine-building.

Investigation of a deadweight force standard machine with a 1 mN – 10 N range

<p>A 10 N small force standard machine with air-bearing support has been developed by NIM. Differing from traditional deadweight force standard machines, this machine is equipped with a balance beam supported by air bearing. The weights of the load frame and deadweight hanging system are balanced, and the initial force is extended to 1 mN. Furthermore, there are innovative designs in the load frame and tension force joint. Performance experiments such as sensitivity, repeatability, and rotation effect are carried out. The uncertainty of this machine is evaluated as 1.0×10<sup>-4</sup> (<em>k</em> = 2) in the range of 1 mN – 0.5 N, 4.0 × 10<sup>-5</sup> (<em>k</em> = 2) in the range of 0.5 N – 10 N. The structure of this force standard machine and its key components are introduced in detail. The performance experimental results and uncertainty evaluation are demonstrated in this paper.</p>

Multiphysics analysis of W7-X control coils

The quasi-symmetric fivefold modular Wendelstein 7-X (W7-X) stellarator consists of three groups of coil systems, i.e. superconducting magnet, trim coil and control coil systems. The control coil system contains ten identical 3D shaped control coils (CC) situated behind the baffle plates of corresponding divertor units, and is designated to rectify the error field and to sweep hot spots on the divertor target plates. The CC is wound from copper conductor with a square cross section of 16 mm × 16 mm and a water cooling hollow of Ø 8 mm. The control coil system was installed in W7-X in 2015, and the integral commissioning has been done in parallel with the completion of W7-X. During the operation phase (OP 1.2a) with limited plasma heating energy, a leakage in one of the CC cooling water plug-in was found and dictates a detailed transient thermal analysis of CC to determine the allowable operation time without cooling water flow. The paper presents the transient thermal analysis and is followed by a detailed finite element mechanical analysis with the consideration of temperature gradient loads, dead weight and electromagnetic forces. Moreover, the transient thermal and mechanical performance of actively cooled CC to be intensively operated during steady state operation phase (OP 2) are also analyzed and evaluated with the same FE model.

Design for 2 MN dead-weight and build-up hybrid force standard machine

Based on the requirement for high accuracy and large range DWM in China. The paper describes a design of the 2 MN dead-weight and build-up hybrid force standard machine, which would be established by Fujian Province Institute of Metrology, Fuzhou, China. The design has covered 1) main specifications; 2) main construction; 3) Finite Element Analysis (FEA) of key units, etc. It solves the technology defects of counter-force phenomenon existing in traditional DWM through rational weights combination and independent loading of each weights. Setting up a servo control method to ensure the loading speed of the weights is controllable, so as to enhance the accuracy of the machine. The build-up system in the DWM is designed to preload and calibrate the dynamometer less than class 0.05. Besides the auxiliary systems designed make the machine more intelligent and convenient.

Comparison on Force Standard Machines between TÜBİTAK UME and SASO NMCC

Bilateral Comparison on dead weight Force Standard Machines using calibration of force proving instrument was carried out between National Metrology Institute of Turkey (TÜBİTAK UME) and National Measurement and Calibration Center at Saudi Standards, Metrology and Quality Organization of the Kingdom of Saudi Arabia (SASO NMCC). In this comparison, TÜBİTAK UME was pilot laboratory and supplied the travelling standard with force transducers. The bilateral comparison is performed by measuring force values taken from force standard machines located in TUBİTAK UME and SASO NMCC. Three different capacities force transducers were determined for this comparison in prepared technical protocol. The comparison was published BIMP database on GULFMET.M.F-S2 code. The comparison was used in project UME-KV-D3-2.10.6.b code. Each participant used their own measurement standards and applied the direct comparison transfer method at comparison. There is a good agreement between TÜBİTAK UME and SASO NMCC results.

Magnetic field influence in deadweight force standard machines: a practical case

The intention of this study is the determination of the influence in uncertainty determination of the possible magnetic interactions in the CEM 500 kN deadweight force standard machine. For this, the magnetic susceptibility of the masses material has been determined as well as the magnetic flux density has been measured in several points. Based on these measurement results a model has been developed to determine the influence of the magnetic interactions with the help of the FEMM software.

NIM’s 100 kN Deadweight Force Standard Machine

A set of 100 kN deadweight force standard machine was developed at National Institute of Metrology (NIM). This machine is capable of realizing force from 1 kN to 110 kN with 1 kN force step both in compression and tension. The machine employs 31 pieces of weights which may be selected optionally to supply force, as a result, there does not exist counter-force during loading process while the machine calibrates the force transducers with different rated capacities. The loading time for each force step is same. The machine is suitable for the type test of load cell in accordance with the international recommendation of OIML R60. This paper introduces the mechanical structure and working principle, the uncertainty evaluation, comparison results with NIM’s other deadweight machines.