9762 papers found
Force measurement holds an important share within the electrical measurement of mechanical quantities in Romania. The paper presents examples that outline the progress in this field, especially in matter of measurement standards and calibration equipment.
Two schemes of possible transducer-based six-component standards are presented. The equations describing the functioning of the apparatuses have been formulated and the analysis of the uncertainty has been performed. Thereupon, information on the achievable metrological behaviours and on the criteria to be adopted for designing some of the mechanical elements is provided.
Testing and certification of load cell families from a few kg up to some 100 t on base of the new OIML R60 (1999) respectively WELMEC 2.4 and OIML R76 are described. New developments of multi-interval load cell design and tests for application in weighing instruments are presented.
At IMEKO - XV World Congress, the design of the first UK national torque calibration machine was described. As part of the design of the machine frame, a structured finite element (FE) study was carried out to predict its behaviour. A series of models were created, with varying levels of idealisation. These were used to evaluate the linearity of response to load application, the deflection and stress states under differing load conditions, and dynamic response using both modal and post-dynamic analysis. The effect of using tubular columns in the upper structure in place of solid bars was...
The IMEKO - XV, World Congress provided the opportunity to describe the design of the first UK national torque calibration machine. Torque is realised by a lever-deadweight system with the transducer under calibration mounted vertically. The vertical deadweight forces are converted to a horizontal torque using castored pulley bearings mounted on a reaction beam positioned underneath the lever beam. The two beams are of identical material construction, consisting of high modulus carbon fibre tubes with stainless steel end fittings and central boss. To provide confidence in the design and...
Electronic balance control of a high precision two-pan flexure-strip mass comparator for double weighing at the UK National Physical Laboratory has been implemented. Critical damping of the freely oscillating loaded beam has been achieved. With a 10 mg differential in 1 kg mass comparisons, steady-state compensation was held for 10 minutes alternatively on either pan, with a stability in mass reading of (standard deviation) 3 parts in 10 -10 of a kilogram. Noise attenuation resulted in signalto- noise ratio of 80 dB on a recovered mass difference signal magnitude of 6 volts dc equating to1...
A dynamic rail weighing system for weighing a ship (or boat) of passing dike is presented in this paper. The system applies wheel measurement to get weigh signal and model-based measurement processing weigh signal, thus weighing a ship (or boat) of passing dike. A scaling method of the rail weighing system based wheel measurement is proposed. This paper discusses thoroughly that the method of model-based measurement processes weigh signals.
The decade series of 10-5-2-2’-1 and 10-5-3-2-1 for submultiples of the unit of mass have been studied to find designs where two comparators are used. The criterion used in finding the designs was to minimize, using the method of least squares, the sum of the absolute values of the elements in the inversion matrices of the normal equations. To date researchers only have reported that when more than one comparator is used in a decade using an orthogonal design for one comparator the orthogonality is lost to produce covariances. However this study has found several cases where orthogonal...
The automatic deadweight machine at the Weighing Instruments Laboratory of the PTB was designed for testing weighing instruments with a maximal load of up to 3 t under varying climatic conditions. The paper reports on the practical operation of the machine for performing legally mandatory weighing tests according to OIML recommendations R76. In particular, critical interference resulting from the wide temperature range of -10°C to +40°C have to be identified and controlled.
This paper concerns the development of an entirely new sensor (called Gyroscopic Force Measuring System, or simply called GFMS) for measuring a force vectorially. The principle and the dynamical characteristics of the GFMS for measuring a force vector are analyzed theoretically. Two auxiliary turntables (driven by servomechanisms) are installed around the gyroscope, in which turntables rotate to follow some angles of incidence of a force vector. Some unfavorable errors caused by various factors are analyzed. A compensation method is proposed as a device both for accurate force measurement...