9762 papers found
The metrological requirements for the mass determination in regard to balances, weights and weighting are discussed, and achievable uncertainties in weightings in the laboratory and in actual practice given.The presentation describes a present situation in mass measurements in Lithuania and provides a technical specification for the establishment of Lithuanian state measurement standard of the mass unit.
The physical model for the subdivision of the kilogram into the decade from 1 kg to 100 g was adapted for the measurement system where weight support plates have to be used. That is the case when combinations of weights with different nominal masses are compared. For this purpose the calibration procedure was modified to eliminate the unknown masses of the support plates. The equation was derived to take into account various influences on the measured mass differences. The influence of the plates on the measurement uncertainty budget and on the estimates of unknown masses of weights was...
The development of new aggregates of mobile machine aims at the reduction of production and operational costs and, at the same time, at the increase of transmitted power when a sufficient reliability is provided. Simultaneously, the real operational safety concerning maximum permissible stress is also rescued. This results in necessity of further more exact methods of design and strength control of aggregate elements.
Paper presents results of the investigation on the magnetoelastic properties of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 alloy in amorphous and nanocrystalline state as stress and force sensor. The new method of applying stress to the ring core of sensor made of soft magnetic material such as nanocrystalline alloys is presented. In this method the distribution of stresses in the ring core is uniform, so even brittle magnetic materials (like nanocrystalline) may be used as stress sensors. The experimental results indicate that stress and force sensor applications require special parameters of the heat...
The paper deals with a strain gauge transducer that can alternatively measure force or pressure. The functional employment of the transducer is explained. In determining the optimal geometry of the elastic element, the authors employ the parametric and feature based CAD modeling, together with the finite element analysis. This ensures flexible and interactive modifications of the geometry and the correlation with the manufacturing process. Finally, the optimal solution is translated and stored in STEP format, a system independent geometric model that is compatible with any modeling...
Contemporary intensive development of technology puts ever-increasing demands on the reliability of products. The increase in the reliability level is emphasised also in transport machines and equipments. This all requires a further improvement of the method of designing and strength checking of a construction. A practical example of loading system analysis in presented which demonstrates use the special instrument to measurement of distribution the force and torsion moment in cardan-joint for control purposes and uses the special instrument to generally measurement of distribution random...
The deadweight loading dependency of the moment-arm length in the torque standard machine (TSM) at NMIJ was suspected of causing deviation in the Interlaboratories Comparison between PTB and NMIJ. The authors attempted to re-verify the moment-arm length and to improve the uncertainty of the arm length in the TSM. Metal bands (MBs) are used for the loading point (called "Reference Line") at both ends of the arm. In an arm balancing test, displacement of the MBs in the arm length direction was measured by eddy current type non-contact sensors during deadweight loading. Additional initial...
A new control- and feedback-control-system for Force and Torque Standard Machines was developed in order to fulfil metrological and functional requirements. Different functionalities were programmed as independent modules, e.g. software modules for deadweight machines with sequential or exchange stack can be linked with modules for lever or hydraulic amplification. During the realisation of the concept, a strict requirement was that the application of the control system is possible to older, existing Standard Machines as well as to new Standard Machines, in order to allow retro-fits and...
In this work we represent our experience in building railroad scales for weighing carriages in motion. A moving train weighing process consists of load cells signal filtration, axle weight calculation and carriage and locomotive identification. We created several filtration algorithms for clearing a load cell signal from bad oscillations that take place in a system. Also we built a carriage identification algorithm that determines how many carriages are being weighed at the moment. The difficulty in this field is that there are a lot of different types of carriages and locomotives on the...
In the strict sense, traceability of torque measurement with rotating torque transducers is given only for non-rotating operation. The presented study examines in how far such proof of traceability is valid also for rotating operation. The method of investigation is a comparison of simultaneous measurements of torque in a rotating shaft train. These consist of measurements with a rotating torque transducer on the one hand and measurements with a cradlemounted absorption dynamometer on the other hand.