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Page 776 of 936 Results 7751 - 7760 of 9356

Yon-Kyu Park, Rolf Kumme, Dae-Im Kang
DYNAMIC INVESTIGATION OF MULTI-COMPONENT FORCE SENSORS USING HARMONIC EXCITATION

This paper describes the dynamic investigation of a 3-component and a 6-component forcemoment sensors using the facilities in the PTB (Physikalisch-Technische Bundesanstalt) in Germany. The 3-component sensor has the transverse forces Fx and Fy of each having 200 N capacity and a twisting moment Mz of 10 N·m capacity and the 6-component sensor has force components Fx, Fy and Fz each having 200 N capacity and moment components Mx, My and Mz each having 20 Nm capacity. The sensitivity of the sensors decreases as the frequency increases and the sensors show almost 90o symmetry due to their geometry.

Jorge C. Torres-Guzmán, Amritlal Sawla, Daniel Ramírez-Ahedo
FORCE STANDARDS COMPARISON BETWEEN PTB (GERMANY) AND CENAM (MEXICO)

A force comparison was carried out between the Centro Nacional de Metrología, CENAM (in Mexico) and the Physikalisch-Technische Bundesanstalt, PTB (in Germany), in order to estimate the level of agreement for the realization of the quantity and the uncertainty associated to its measurement. The comparison was carried out in a range starting at 2 kN and up to 150 kN. In order to achieve best accuracy of the force transducers used was made of 5 sub ranges (5 kN, 20 kN, 50 kN, 100 kN and 150 kN). The results obtained, the deviations graphs that include the uncertainty for each laboratory are presented in this document.

Heikki Kajastie, Jorma Manninen, Kari Riski
DENSITY CALIBRATIONS AT MIKES

The density measurement instruments at MIKES will be described. Also a construction of a instrument for weights 1 g – 200 g will be presented. The main test results will be given.

Željko Alar, Mladen Franz
TRACEABILITY IN FORCE MEASUREMENT IN REPUBLIC OF CROATIA

In this study, based on results of the previously performed calibrations and factory specifications, an analysis of force measurement equipment in Republic of Croatia has been done. Transfer force standards of the Laboratory for Testing Mechanical Properties ( LIMS) have been calibrated in HBM, Germany. Calibration curves for specific transfer standards were obtained, to be used for estimation of standard uncertainties. Also, expanded measurement uncertainty was calculated at each measuring point, according to the document EA-4/15. This was used for determining the best measuring capability of the Laboratory, as well as for developing of the equipment calibration scheme for force measurement in Croatia. The previous and last calibration results for the same transfer standards were compared and, further to it, certain conclusions were made on how characteristics of the standards are influenced by use during certain period of time.

C. Ferrero, C. Marinari
CHARACTERISATION OF REFERENCE TORQUE WRENCHES BY THE IMGC SIX-COMPONENT CALIBRATION SYSTEM

This paper describes the metrological characterisation of two Reference Torque Wrenches (RTW) of 100Nm and 500Nm capacity. The characteristics of the torque sensors were evaluated by using the IMGC-CNR sixcomponent calibration system (EUROMET agree facility, project 113). The repeatability of the absolute variation of the output signal of the two TTS under the application of the different spurious components, referred to the R.O., is in general of the order of 5·10–5. The sensitivity to spurious components are normally better than 2·10–3 of the nominal torque.

Carlo Ferrero, Carlo Marinari
THE DISSEMINATION OF THE FORCE UNIT IN ITALY: CALIBRATION OF MATERIAL TESTING MACHINE INTERCOMPARISON

One of the most important activities at European (EA) and National level of the National Accreditation Body (NAB) is the organisation of a series of interlaboratory comparisons (ILC), to verify the measurements capability of the calibration laboratories. In 2001 one ILC, for the calibration of uniaxial testing machines, was organised in Italy by SITIMGC with the IMGC-CNR as reference laboratory. In the present paper the main results obtained during the ILC are discussed, in particular a regression analysis was applied to evaluate the differences on the repeatability and accuracy given by the different laboratories.

Kamlesh K. Jain, S.K. Jain
BEST MEASUREMENT CAPABILITY OF THE NEWLY DEVELOPED 5 kN DEAD WEIGHT FORCE MACHINE

This paper describes the salient features and the results of metrological performance of the newly developed 5 kN dead weight force calibration machine. Two well characterized strain gauge force transfer standards of 2 and 5 kN full capacity having repeatability better than 0.002% in compression mode were used to derive the best measurement capability of ± 50 ppm (k = 2) of the machine.

Jin-Wan Chung, Kyung-Ho Chang, Woo-Gab Lee, Kwang-Pyo Kim
AIR DENSITY DETERMINATION USING 1 KG BUOYANCY MASS COMPARISON(III)

In calibration of secondary 1 kg stainless steel mass standard from a platinum-iridium kilogram prototype, a major uncertainty arises from the measurement of air density for the buoyancy correction. This paper is continued to the reference. An experimental determination of air density using buoyancy pairs and a vacuum balance has been carried out and its results were compared with those of the CIPM formula 81/91. The environmental measurement instruments used for this experiment are different from those previously used. Also the true mass difference between buoyancy pairs in vacuum was measured at mass laboratory of NMIJ in Japan and compared with the KRISS result. The disagreement between air density measurements by the 1 kg BA-pair and those by CIPM formula is 5.1 x 10-4 kg/m³, but the standard deviation of the difference between both methods has been improved, to 5.3 x 10-5 kg/m³ compared to 1.5 x 10-4 kg/m³ by the previous experiment.

Miroslav Kopecky, Ivan Letko, Vladimir Cuth, Jan Vavro
TESTING EQUIPMENT FOR FATIGUE TESTS OF STEEL CORDS

The contents of the paper point out the necessity of combining the theoretical and experimental approaches in the investigation of tyre load in vehicles. The models are planar and they model the cross-section of the tyre enabling the consideration of the bottom load and the internal pressure in the tyre, as well as the influence of the lateral force. The paper presents the findings, the formulations necessary for solving the task obtained in the experimental model tests and serving as a basis for comparison with the results obtained from purely theoretical approaches, e.g. by the method of finite elements, with identical load conditions.

Jongho Kim, Yonkyu Park, Daeim Kang
DESIGN AND FABRICATION OF A THREE-COMPONENT FORCE SENSOR USING MICROMACHINING TECHNOLOGY

This paper describes a design methodology of a tri-axial silicon-based force sensor with square membrane by using micromachining technology (MEMS). The sensor has a maximum force range of 5 N and a minimum force range of 0.1 N in the three-axis directions. A simple beam theory was adopted to design the shape of the micro-force sensor. Also the optimal positions of piezoresistors were determined by the strain distribution obtained from the commercial finite element analysis program, ANSYS. The Wheatstone bridge circuits were designed to consider the sensitivity of the force sensor and its temperature compensation. Finally the process for microfabrication was designed using micromachining technology.

Page 776 of 936 Results 7751 - 7760 of 9356