9762 papers found
This paper describes the design and working principle of a new multicomponent torque standard machine with a torque range of 5 MN·m. The design was in particular optimized to reduce the influences of parasitical components on the main torque component.
The creep and creep recovery are important characteristics of Build-up system (BU-system). So, this paper is focused on the creep and creep recovery of several BU-systems. The creep and creep recovery of two different types of force transducers, including RTN and column type, are measured when applied 20%, 40%, 60%, 80%, and 100% of the rated loads and after unloading, respectively. Afterward built-up by these transducers, BU-systems with different structures and capacities are measured in order to investigate the creep and creep recovery behaviors of them and the differences between the...
In order to obtain accurate torque measurements in harsh condition, such as underwater, a torque transducer based on fiber Bragg grating is proposed in this paper. According to optimized deformation element design and fiber Bragg grating patching tactic, the new proposed torque transducer realizes accurate torque detection with automatic compensations of temperature and bending moment as well as avoiding influences from environment. The accuracy of the torque transducer, as well as its underwater performance are tested by calibration tests both in air and in underwater environment,...
The paper develops a negative step dynamic torque calibration machine and illustrates its working principle and critical technologies. The use of retracting actuators reduces significantly the fall time of the negative step torque, whereas air bearing yields high transfer accuracy of the dynamic torque. The experimental study is conducted and the results show that the fall time of the step torque reaches to millisecond level and the dynamic response up to 5800 Hz can be excited. Through uncertainty analysis, the expanded uncertainty of the presented calibration machine is better than 5 % ( k...
This research is to investigate the possibility of calibrating a strain cylinders using laser interferometry, thus to provide a new type of transducer that can provide both force and deformation indications. This new method for calibration of strain cylinders is based on application of a double channel laser interferometer in a force standard machine. Experimental results show that the deformation of a strain cylinder has a definite and stable relationship with the force applied, and can be calibrated and directly traced to the wavelength of laser.
This paper describes PTB’s new 200 kN deadweight force standard machine with a large force range from 50 N up to 200 kN with lowest relative uncertainties of 0.001% in the range from 5 kN up to 200 kN which was possible by using deadweights of stainless steel in the quality of mass standards of class F1. The deadweights are adjusted according the gravity value and the masses are then determined with a relative expanded uncertainty of 3 × 10 -6 . This maschine allows the investigation and calibrate force transducers in tension and compression without changing the installation position so that...
A micro/nano force measurement method is proposed in this paper. Viscous damping is introduced to optimize system stability and reduce interference from mechanical vibration. The resolution of the shadow method was approximately 4 nN.
One impulse force device is set up in CIMM to calibrate force transducers’ sensitivities with dynamic method. The free falling weight impacts the calibrated force transducer to generate large-amplitude impulse force up to 200 kN with (1~10) ms pulse duration, and one extra small inertia mass is installed on the top of the falling mass to generate small impulse force down to 20 N. The impulse force is measured by laser interferometer to trace the force to mass, time and length. Several piezoelectric transducers are calibrated with the impulse force calibration device and the amplitude...
This paper presents recent theoretical and experimental investigations of calibration measurements of impact hammers using different dynamic calibration set-ups with primary traceability methods. In the scope of a scientific collaboration between the German national metrology institute PTB and the Mexican CENAM, measurements of selected hammers were conducted at both institutes. The analysis of the measurement signals in the time and frequency domain is presented and discussed. modal hammer, dynamic calibration, shock force, sensitivity
The accurate measurement on the compressibility coefficient of density standard liquid at 2329kg/m 3 (DSL-2329) plays an important role in the quality control for silicon single crystal manufacturing. A new method is developed based on hydrostatic suspension principle in order to determine the coefficient with high measurement accuracy. Two silicon single crystal samples with known density are immersed into a sealed vessel full of DSL-2329. The density of liquid is adjusted with varying liquid temperature and static pressure, so that the hydrostatic suspension of two silicon single crystal...