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K. Fukuda, K. Kameoka, T. Ono, K. Yoshida
EVALUATIONS OF A NEW MASS-ESTIMATION METHOD FOR AXLE WEIGHTS OF IN-MOTION VEHICLES USING VEHICLE MODELS

An axle weighing system is a system that measures each axle weight of in-motion vehicles while they pass though on the weighbridge. In the weighing, signal processing technique is the key to achieve the precise measurement since the output signal from the weighbridge is contaminated with the noise due to the vibration of the vehicle in motion. In our previous paper, we proposed a new signal processing method using normal equations to estimate the vibration parameters. In the present paper, we examined the relation between the velocities of in-motion vehicles and the estimated values obtained with the new method, through a consideration on the computer simulation with the output signal generated by using the linear models of vehicles. As a result, it was clarified that precise estimation is possible when the velocity of a vehicle is approximately less than 15 km/h.

Z. Demirel Atasoy
APPLICATION OF THE MEASUREMENT METHODS USING THE TRANSFORMED MECHANICAL QUANTITIES IN TO ELECTRICAL QUANTITIES ON FARM MACHINERY EXPERIMENTS

Some physical quantities are used for design of the various machine prototype, improvement research and determination of the operating circumstances. These physical quantities, which are widely known, are tension-compression forces, moment, distance, velocity, vibration, flow rate, pressure and revolution per minute values. Such parameters can be measured by appropriate measurement techniques. Nowadays, every kind of mechanical quantities can be converted electrical signal, transmitted, recorded or processed by electronic components. Physical properties of materials change under mechanical effects. The inductance, capacitance, resistance, reluctance and voltage of mineral materials vary if they expose to pressure. Thus, the pressure changes influencing on the material occur and mechanical changes transform into electrical signal in the electrical circuit. These converting methods are used a lot of areas in the agricultural machinery experiments; for example predicting the draught forces of tillage equipments, determination of loads on tractor structures or soil failure caused by subsoilers, and a general purpose tractor instrumentation.

S. Fank, M. Demirkol
EFFECT OF HARDNESS ON CREEP RESPONSE OF STRAIN GAGE BASED FORCE TRANSDUCER USING AISI 4340 STEEL AS SPRING MATERIAL

Creep problem of spring materials plays an effective role on the performance of force transducers. Several heat treatments can be applied to spring materials in order to minimize creep response. The effect of heat treatment on creep properties of AISI 4340 steel was investigated in this study. The tensile specimens of AISI 4340 steel were austenitized and oil quenched, and then tempered to 35, 45 and 55 Rockwell-C hardness levels. After proper heat treatment and final machining of column type specimens, the preparation of tensile force transducers was completed by bonding special-class transducer strain-gages onto them and constructing necessary Wheatstone bridge circuits. Then all force transducers were loaded in a dead-weight force standard machine to measure the related creep response. It was observed that heat treatment (and the resulting martensitic structure) of the spring material had a major effect on the performance of the transducer, particularly where creep response was concerned. Since the minimization of creep problem had prime concern, best results could be achieved in transducers consisting the hardest spring material.

E. Bilgiç, B. Karaböce, E. Sadikoglu, S. Fank
INFLUENCE OF MECHANICAL VIBRATION ON STRAIN GAUGE BASED FORCE TRANSDUCER PERFORMANCE

This paper deals with the influence of mechanical vibration on the performance of strain-gauge based force transducers. Force transducers of beam bending with binocular type were used for investigations. The transducers with different capacities varying in the range of 3 – 30 kg were loaded by the calibrated masses and excited by discrete accelerations levels at a certain frequency. The difference in electrical output of transducer caused by mechanical vibration has been determined. Resonance curves of the transducers have been obtained by frequency sweep measurements under loaded conditions.

F. Tigrel, S. Fank, H. Kaya
A NEW 500 KG LOAD CELL TEST DEAD-WEIGHT MACHINE FOR LOS ACCORDING TO OIML R60 AND PERFORMANCE TESTS REALISED BY UME

In order to test load cells used according to OIML R60 regulation in different temperature such as –10, 20 and 40°C with increasing and decreasing loading conditions, dead-weight machine and good temperature control cabinet are necessary. ESIT Company has been manufacturing different type and capacities load cells in the last 12 years in Istanbul. In order to improve product quality and accuracy of ESIT load cells, a new dead-weight machine was designed and manufactured in ESIT Factory. This machine is capable to testing the compression load cells up to 500 kg. In this machine, quick loading and unloading for creep test purposes is realized by newly developed lever arm mechanism. Since temperature control cabinet restricts the movement of load cells up and down, this mechanism was developed to move loading frame of machine. UME Mass Laboratory calibrated to each dead weight. UME Force Laboratory realized a performance test of this machine using UME transfer force transducer.

C. Ferrero, C. Marinari
LONG-TERM STABILITY OF THE IMGC REFERENCE FORCE TRANSDUCERS UP TO 9 MN

Force transducers are calibrated using dead-weight, lever multiplication or hydraulic multiplication standard machines. For very large capacities, in general above 1 MN, the "build-up" method may be employed, consisting of comparing the dynamometer to be calibrated with one or more dynamometers linked in parallel. With the "build-up" method the field of force measurement may be extended to values that would not appear possible with the use of dead-weight or multiplication primary standards, at a much lower cost. The present paper reports the evolution over time, that is the long term stability of the metrological characteristics (calibration factors, repeatability, hysteresis and zero variations at no load) of two reference transducers (3 MN and 9 MN respectively) used to calibrate force transducers at IMGC-CNR.

Aimo Pusa
NORDIC INTERCOMPARISON OF CALIBRATION OF THE MATERIAL TESTING MACHINES: REPORT OF THE FORCE CALIBRATION

For us there was not known intercomparison for the calibration of uniaxial testing machine. It was the reason to work out this kind of comparison during the year 1999. By planning the comparison there was two main problems by this kind of comparison. The first one; the object can not be circulated from calibrating laboratory to next one. The second one is that the testing machine should be measured to get the status of a reference standard. The first problem was solved tat every laboratory had to travel to the location, where testing machine was. Second problem meant that the history of testing machine should be known well and the calibration of the pilot should be made very careful. FINAS has organized this intercomparison for the calibration of the uniaxial testing machine in the year 1999 in Finland. There was three laboratories participating the comparison, two from Finland and one from Denmark. The results has shown some main problems:
- The stability of the testing machine must be investigated well
- The calibration method for force has high importance
This paper gives some numerical value of these problems and the experiences during the intercomparison.

S. Kurosu, K. Kodama, M. Adachi, K. Kamimura
ERROR ANALYSIS FOR GYROSCOPIC FORCE MEASURING SYSTEM

This paper concerns the development of a new type of force sensor called Gyroscopic Force Measuring System, (simply called GFMS) for measuring a force vectorialy. The GFMS realized a highly accurate measurement using an estimator for the unknown angles of incidence of a force vector. The estimator, however, assumed an exact knowledge on the dynamical equations in the steady-state. This caused much degradation in the measurement accuracy unless the steady-state of the GFMS could be attained. The estimation errors of the angles of incidence directly affect the accurate measuring of the force. We can get the better performance by choosing the adequate damping coefficient of gyroscope (for nutation mode). From the error analysis, some essential information for designing the GFMS is highlighted.

J. C. T. Guzmán, D. R. Ahedo, J. P. Cruz, J. M. E. Saffar
FORCE STANDARDS COMPARISON BETWEEN MEXICO AND BRAZIL

A force comparison was carried out between Brazil and Mexico, in order to estimate the level of agreement for the realisation of the quantity. The comparison participants were two secondary laboratories (CETEC and IPT/SP) and the national metrology institute (INMETRO) from Brazil and the national metrology institute (CENAM) from Mexico. The comparison was carried from 20 kN to 150 kN, using two load cells as comparison standards, having 1·10-5 relative repeatability each. Resumes of the general guidelines and procedure used for the comparison as well as the results obtained, deviations Figure for each participant laboratory are here included.

J. C. T. Guzmán, D. R. Ahedo, J. P. Cruz
DEAD WEIGHT FORCE MACHINES COMPARISON WITHIN THE INTERAMERICAN METROLOGY SYSTEM (SIM) UP TO 150KN

A force comparison was carried out within the Interamerican Metrology System (SIM), in order to estimate the level of agreement for the realisation of the quantity, and the uncertainty associated to its measurement. The comparison participants were the National Metrology Institutes (NMI´s) from SIM with dead weight machines: United States of America, Brazil and Mexico. The comparison was carried out up to 150 kN, using a load cell as the standard, having 1·10-5 relative repeatability. The "Centro Nacional de Metrología"(CENAM), in Mexico, was the co-ordinator and pilot laboratory. The results obtained, deviations graph including the uncertainty for each participant laboratory are presented in this document.

Page 700 of 977 Results 6991 - 7000 of 9762