A still unsolved problem in the field of metrology is the definition of the SI unit kg in terms of universal physical constants as it was done for the other fundamental SI units. One possibility is to accumulate ions up to a weighable mass. Then the atomic mass unit can be determined by measuring the total charge and mass of the accumulated ions. This article describes the ion optical properties of an existing experiment for ion accumulation at the PTB. Results of the ion optical calculations are used for experimental settings to measure mass spectra of a mixed xenon gold ion beam.
The investigation of the roll brake testers used testing for trucks has been made during year 2002. There have been developed a test trail, reported in TC-3 Congress Celle 2002. The aim of this investigation was to get information about real measurement capability of the roll brake testers used in inspection of the trucks for Finnish authority (The Finnish Vehicle Administration AKE). The usually way to calibrate roll brake tester has been to generate the reference force direct against of the force measurement transducer. This calibration does neither take in to account the mechanical...
This paper deals with the specification of method accuracy enhancement for unsteady aerodynamic forces and moments in an airfoil cascade. These forces are induced by forward and angular vibrations of airfoils. The improvement is achieved by taking airfoil and other elements deformations in consideration in the calibration and measurement process.
This contribution deals with possible reasons for the non-linear behaviour of piezoelectric force transducers, previously unknown. Possible reasons are interactions between isotropic elements such as force introduction and the anisotropic piezoelectric sensor element, geometrical non-linearities of the force transducer and non-linearities of the piezoelectric material. This paper discusses the influence of geometrical nonlinearities. A theory for analytical modelling of piezoelectric force transducers is developed and presented.
A newly developed measuring device allows the generation and measurement of arbitrarily directed forces and moments. This device consists of a driving unit for generating the loads and a measuring unit for the accurate measurement of the acting components. Both units are realized as hexapod structures with the same geometry but mirrored arrangement. This paper describes the metrological characterization of the hexapods of this multi-component measuring device.
Many mechanical quantities in metrology are affected by the local gravity. Modern gravimetric methods allow to determine the local gravity value with sufficient accuracy, but the effort is still time consuming and expensive. An interpolation within available gravity databases mostly does not suffice because of an inadequate data density compared with the heterogeneous field. This study gives a short overview of today’s most important representations of the physical gravity field. The classical methods will be introduced from the perspective of the usability in metrology and compared to some...
In this contribution a new force measuring facility for the range from 10 mN to 10 N consisting of a piezoelectric adjustment unit and a precision compensation balance is presented. A metrological characterization of the individual components of the device and first results of an examination of a force transducer using the new force measuring facility are given.
The purpose of this lecture is to show the problems which must be taken into account by the designer in constuction of miniature semiconductor strain gauges for dynamic measurements of yarn tension and to give practical methods for identification of static and dynamic behaviour and a design of such transducer.
The designs for submultiples of the unit of mass have been studied to find designs where two comparators are used. This study has found several cases where orthogonal designs can be used for using two comparators in a decade. Even though the orthogonal designs are for the case where the ratio of the comparator’s standard deviation is 2, simulation showed extended values of the ratio could be used to reduce variances with the orthogonal designs.
This paper describes the unique features and metrological performance of a new 55 kN / 2200 kN lever deadweight force standard machine set up recently at SPRING Singapore. It uses a novel 55 kN deadweight stack with individual mass disk drives, a single lever of 40 times multiplication ratio and a 2.2 MN tension-compression loading device. The machine is of increased capacity, with a wider force range and larger amplification ratio than previously possible. The lever machine covers force range from 10 kN up to 2200 kN in intervals of 10 kN. For the first time, a force standard machine of...