scholarly journals Development of 1.6 GPa pressure-measuring multipliers

ACTA IMEKO ◽  
2014 ◽  
Vol 3 (2) ◽  
pp. 54 ◽  
Author(s):  
Wladimir Sabuga ◽  
Rob Haines
Keyword(s):  
Finite Element Analysis ◽  
Reasonable Agreement ◽  
Standard Uncertainty ◽  
Feasibility Analysis ◽  
Element Analysis ◽  
Relative Standard Uncertainty ◽  
Pressure Calibration ◽  
Relative Standard ◽  
New Development ◽  
Theoretical Results

Two 1.6 GPa pressure-measuring multipliers were developed and built. Feasibility analysis of their operation up to 1.6 GPa, parameter optimisation and prediction of their behaviour were performed using Finite Element Analysis (FEA). Their performance and metrological properties were determined experimentally at pressures up to 500 MPa. The experimental and theoretical results are in reasonable agreement. With the results obtained so far, the relative standard uncertainty of the pressure measurement up to 1.6 GPa is expected to be not greater than 2·10<sup>-4</sup>. With this new development the range of the pressure calibration service in Europe can be extended up to 1.5 GPa.

Progress toward Système International d'Unités traceable force metrology for nanomechanics

2004 ◽  
Vol 19 (1) ◽  
pp. 366-379 ◽  
Author(s):  
Jon R. Pratt ◽  
Douglas T. Smith ◽  
David B. Newell ◽  
John A. Kramar ◽  
Eric Whitenton
Keyword(s):  
Atomic Force Microscope ◽  
Electrostatic Force ◽  
Standard Uncertainty ◽  
National Standards ◽  
Force Balance ◽  
Traceability Chain ◽  
Relative Standard Uncertainty ◽  
Force Sensitivity ◽  
Atomic Force ◽  
Relative Standard

Recent experiments with the National Institute of Standards and Technology (NIST) Electrostatic Force Balance (EFB) have achieved agreement between an electrostatic force and a gravitational force of 10−5 N to within a few hundred pN/μN. This result suggests that a force derived from measurements of length, capacitance, and voltage provides a viable small force standard consistent with the Système International d’Unités. In this paper, we have measured the force sensitivity of a piezoresistive microcantilever by directly probing the NIST EFB. These measurements were linear and repeatable at a relative standard uncertainty of 0.8%. We then used the calibrated cantilever as a secondary force standard to transfer the unit of force to an optical lever–based sensor mounted in an atomic force microscope. This experiment was perhaps the first ever force calibration of an atomic force microscope to preserve an unbroken traceability chain to appropriate national standards. We estimate the relative standard uncertainty of the force sensitivity at 5%, but caution that a simple model of the contact mechanics suggests errors may arise due to friction.

scholarly journals Analytical Compliance Equations of Generalized Elliptical-Arc-Beam Spherical Flexure Hinges for 3D Elliptical Vibration-Assisted Cutting Mechanisms

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5928
Author(s):  
Han Wang ◽  
Shilei Wu ◽  
Zhongxi Shao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Flexure Hinge ◽  
Matrix Formulation ◽  
Element Analysis ◽  
Compliance Matrix ◽  
Flexure Hinges ◽  
Elliptical Vibration ◽  
Relative Standard ◽  
Cutting Mechanisms

Elliptical vibration-assisted cutting technology has been widely applied in complicated functional micro-structured surface texturing. Elliptical-arc-beam spherical flexure hinges have promising applications in the design of 3D elliptical vibration-assisted cutting mechanisms due to their high motion accuracy and large motion ranges. Analytical compliance matrix formulation of flexure hinges is the basis for achieving high-precision positioning performance of these mechanisms, but few studies focus on this topic. In this paper, analytical compliance equations of spatial elliptic-arc-beam spherical flexure hinges are derived, offering a convenient tool for analysis at early stages of mechanism design. The mechanical model of a generalized flexure hinge is firstly established based on Castigliano's Second Theorem. By introducing the eccentric angle as the integral variable, the compliance matrix of the elliptical-arc-beam spherical flexure hinge is formulated. Finite element analysis is carried out to verify the accuracy of the derived analytical compliance matrix. The compliance factors calculated by the analytical equations agree well with those solved in the finite element analysis for the maximum error; average relative error and relative standard deviation are 8.25%, 1.83% and 1.78%, respectively. This work lays the foundations for the design and modeling of 3D elliptical vibration-assisted cutting mechanisms based on elliptical-arc-beam spherical flexure hinges.

scholarly journals Extraction of Load Information From Photoelastic Images Using Neural Networks

2006 ◽  
Author(s):  
Venketesh N. Dubey ◽  
Gurtej S. Grewal ◽  
Denzil J. Claremont
Keyword(s):  
Neural Networks ◽  
Finite Element Analysis ◽  
Biomedical Engineering ◽  
Stress Pattern ◽  
Field Analysis ◽  
Element Analysis ◽  
Sensing Applications ◽  
Fringe Patterns ◽  
Theoretical Results ◽  
And Robotics

Photoelastic materials develop colored fringes under white light when subjected to mechanical stresses which can be viewed through a polariscope. This technique has traditionally been used for stress analysis of loaded components, however, this can also be potentially used in sensing applications where the requirement may be measurement of the stimulating forces causing the generation of the fringes. This leads to inverse photoelastic problem where the developed image can be analyzed for the input forces. However, there could be infinite number of possible solutions which cannot be obtained by conventional techniques. This paper presents neural networks based approach to solve this problem. Experiments conducted to prove the principle have been verified with theoretical results and finite element analysis of the loaded specimens. The technique, if fully developed, can be implemented for any generalized case involving complex fringe patterns under different loading conditions for whole-field analysis of the stress pattern, which may find application in a variety of specialized areas including biomedical engineering and robotics.

Numerical Analysis of Quasi-Static Out-of-Plane Compression of Miura-Ori Patterned Sheets

2019 ◽  
Author(s):  
Xinmei Xiang ◽  
Guoxing Lu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cell Wall ◽  
Parametric Analysis ◽  
Reasonable Agreement ◽  
Dihedral Angles ◽  
Element Analysis ◽  
Out Of Plane ◽  
Plane Compression ◽  
Simulation Results

Abstract In this paper, quasi-static out-of-plane compression behaviors of Miura-ori patterned sheets were investigated numerically by using finite element analysis (FEA). The simulation results show a reasonable agreement with the experimental results. In addition, the parametric analysis of the Miura-ori patterned sheets with different cell wall thicknesses, side lengths, dihedral angles and sector angles were carried out using FEA method. The influences of different parameters on the peak force and mean force were determined.

Structural Optimization Design of Anti-Collision Sealing Cylindrical Rubber Cushion

2012 ◽  
Vol 201-202 ◽  
pp. 894-897
Author(s):  
Jun Liu ◽  
Bao Shou Sun ◽  
Jian Nan Cao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optimal Design ◽  
Water Surface ◽  
Optimization Design ◽  
Feasibility Analysis ◽  
Ansys Software ◽  
Element Analysis ◽  
Good Ability ◽  
Air Cushion

At present, it is inconvenient for use due to huge volume of common inflatable rubber fender. This paper introduces a design of cylindrical rubber sealing cushion which can be applied to various occasions to protect ships, dock and pier facilities. The key of air cushion technique is that it can produce a large displacement to buffer deformation and to reduce the exchange of energy. It plays a role to increase the time of collision, and then reduces the force of collision. Meanwhile, it also has good ability to adapt the tilted contact and it can float on the water surface, etc. This paper makes a feasibility analysis and strength calculation by doing theoretical calculation, and then making a force-test simulation by using ANSYS software, and do some structure optimal design according to the results of finite element analysis.

Conformal Contact Between a Rubber Band and Rigid Cylinders

2012 ◽  
Vol 79 (4) ◽  
Author(s):  
Takuya Morimoto ◽  
Hiroshi Iizuka
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rubber Band ◽  
Element Analysis ◽  
Geometrical Nonlinearities ◽  
Pressure Distributions ◽  
The Finite Element Analysis ◽  
Theoretical Results ◽  
Conformal Contact ◽  
Good Agreement

We consider a conformal contact problem between a rubber band and rigid cylinders that involves geometrical and material nonlinearities. The rubber band is assumed to be incompressible, neo-Hookean rubber. From the geometry and elasticity of the band, we present simple formulas to estimate the force–stretch relations and the contact pressure distributions on the cylinder. We show that the theoretical results are in good agreement with those of the finite element analysis when the rubber band is thin enough to be negligible to the bending stiffness. This verifies that the theory can effectively take into account both the material and geometrical nonlinearities of the band under the present conditions.

scholarly journals The New 1 kN·m Torque Standard Machine in National Institute of Metrology, China

2021 ◽  
Vol 2095 (1) ◽  
pp. 012072
Author(s):  
Jile Jiang ◽  
Kun Wu ◽  
Bin Guo ◽  
Shi Wu ◽  
Zhimin Zhang
Keyword(s):  
Ambient Temperature ◽  
Radial Direction ◽  
Standard Uncertainty ◽  
Aerostatic Bearing ◽  
Horizontal Alignment ◽  
Relative Standard Uncertainty ◽  
Lever Arm ◽  
Precise Adjustment ◽  
Relative Standard ◽  
Minimum Deformation

Abstract A 1 kN-m deadweight torque standard machine is established in National Institute of Metrology, China. The torque range is 5N·m-1200 N·m. The deadweights utilized in the machine can generate the torque of 1200 N·m, 600N·m, 360N·m, 240N·m, 120N·m and 60 N·m, respectively. The torque can be applied both in clock-wise and counter clock-wise direction in sequencial loading process. The aerostatic bearing is introduced to the torque standard machine in order to eliminate the influence of friction. The symmetric V type rotor and stator are used to provide the reliable support both in axial and radial direction. The material of the lever arm is invar alloy, performing with the minimum deformation with the change of the ambient temperature. The counter torque part will make the precise adjustment to make a horizontal alignment of the lever arm. The relative standard uncertainty of the torque generated by the machine is less than 1e-5.

scholarly journals Detonation Velocity Measurement with Chirped Fiber Bragg Grating

Sensors ◽  
2017 ◽  
Vol 17 (11) ◽  
pp. 2552 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Detonation Velocity ◽  
Velocity Measurement ◽  
Standard Uncertainty ◽  
Performance Estimation ◽  
Relative Standard Uncertainty ◽  
Dual Channel ◽  
Explosive Performance ◽  
Relative Standard ◽  
Chirped Fiber Bragg Grating ◽  
Propagation Prediction

Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are pasted both on the surface and in the center of the explosive cylinder. The length of CFBG sensors is measured via the hot-tip probe method. The light intensity reflected from the CFBG sensors attached to the explosive is transformed to voltage, and the voltage–time is then measured with the oscilloscope. According to the five experiments results, the relative standard uncertainty of detonation velocity is below 1%.

Nonlinear static modeling of a tip-tilt-piston micropositioning stage comprising leaf-spring flexure hinges

2020 ◽  
Vol 234 (10) ◽  
pp. 1969-1978
Author(s):  
Guozhen Chen ◽  
Pinkuan Liu ◽  
Han Ding
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Leaf Spring ◽  
Element Analysis ◽  
Flexure Hinges ◽  
The Finite Element Analysis ◽  
Static Modeling ◽  
Nonlinear Static ◽  
Force Displacement ◽  
Theoretical Results

Nonlinear static modeling is crucial for the design of stages with large travel ranges. However, few studies have investigated complex spatial compliant mechanisms. The present study proposes an optimization algorithm based on substructure constraint conditions to formulate the nonlinearity of the force–displacement characteristic of a tip-tilt-piston stage comprising leaf-spring flexure hinges. First, the nonlinear force–displacement characteristics of the compound basic parallelogram mechanism are derived using an optimization algorithm based on two constraint conditions (I and II). Second, the nonlinear static modeling of the tip-tilt-piston stage is conducted based on the modeling results of the compound basic parallelogram mechanism. The stage is divided into three parts, and force analyses are conducted for all three parts. The vertical displacement of the compound basic parallelogram mechanism in part 1 and the rotational angle of the rotational plate in part 2 are calculated. Subsequently, the force–displacement characteristics of the tip-tilt-piston stage are obtained based on a third constraint condition (III). A comparison of the finite element analysis results and the theoretical calculation indicates less than 4% errors. In the experimental tests conducted on the proposed stage and four compound basic parallelogram mechanisms, the displacements were evidently larger than those calculated using the finite element analysis. Therefore, a weight coefficient of the axial force w is introduced in the theoretical calculation to solve the problem of the large deviations between the experimental results and the finite element analysis results. When w is set to 1, the theoretical results are in good agreement with the finite element analysis results; when w is set to 0.05 for the tip-tilt-piston stage and 0.15 for compound basic parallelogram mechanisms, the theoretical results are consistent with the experimental results (less than 8.5% errors).

UNCERTAINTY OF MEASUREMENT IN THE RESPONSE TEST OF A THYROID MONITOR

2019 ◽  
Vol 184 (3-4) ◽  
pp. 531-534 ◽  
Author(s):  
Akira Yunoki
Keyword(s):  
Measurement Uncertainty ◽  
Radiation Protection ◽  
Scintillation Detector ◽  
Standard Uncertainty ◽  
Uncertainty Of Measurement ◽  
Test Device ◽  
Response Test ◽  
Relative Standard Uncertainty ◽  
Detector Distance ◽  
Relative Standard

Abstract A test device consisting of an I-131 source, a phantom on a 3D moving table, and a NaI(Tl) scintillation detector on a fixed flat table was developed to carry out response tests of a thyroid monitor. A measurement uncertainty due to variation of configuration of the source and the detector, as well as other factors, was estimated. The estimated relative standard uncertainty of measurement at a source–detector distance of 100 mm, which was deduced to be the optimum, was 1.9%. This is sufficiently small for calibrating a thyroid monitor used for radiation protection.

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