Behaviour of brazed pipe flanges with separate clamping rings

1975 ◽  
Vol 10 (2) ◽  
pp. 71-76 ◽  
Author(s):  
H Fessler ◽  
D A Perry
Keyword(s):  
Surface Finish ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Resistance Strain ◽  
Strain Gauges ◽  
Material Surface ◽  
Surface Finishes ◽  
Gasket Material ◽  
Internal Pressures ◽  
Electrical Resistance Strain

Three pairs of aluminium-brass 100-mm-bore flange models with different surface finishes of the joint faces have been subjected to known bolting forces and internal pressures up to seven times the rated pressure at room temperature. Hard and soft flat gaskets were used and it was found that the joint efficiency was independent of gasket material, surface finish, and initial bolt tension. Surface strains on the outer surfaces of the tubes and flange rings were measured with electrical-resistance strain gauges where these could be fitted. These results are also presented. The flanges did not fail; tests ended when the loose steel rings touched owing to excessive deformation, so that the gaskets were prevented from sealing.

scholarly journals Field Techniques for Experimental Stress Analysis in Arctic Sea Ice

1980 ◽  
Vol 25 (91) ◽  
pp. 175-182
Author(s):  
G. V. B. Cochran
Keyword(s):  
Sea Ice ◽  
Electrical Resistance ◽  
Three Dimensional ◽  
Arctic Sea Ice ◽  
Resistance Strain ◽  
Strain Gauges ◽  
Experimental Stress Analysis ◽  
Arctic Sea ◽  
Glacier Ice ◽  
Electrical Resistance Strain

AbstractIncreasing interest is being directed toward studies involving measurement of strain and strain-rates in sea and glacier ice. A number of techniques for obtaining these data over gauge lengths ranging from 1 m to several kilometers have been reported, but there has been little experience with shorter lengths. Use of commercially available electrical resistance strain-gauges (length 5–20 cm) intended for embedment in concrete offers a new approach in which multiple gauge, two- and three-dimensional arrays can be installed in ice with minimum effort and monitored with portable equipment. This report describes a pilot study designed to demonstrate the use of three types of electrical resistance strain gauges in sea ice under exposed field conditions. Results include detection of variations in strain fields related to tidal currents.

Mechanical Hysteresis in Force Transducers Manufactured from Precipitation-Hardened Stainless Steel

1995 ◽  
Vol 209 (2) ◽  
pp. 125-132 ◽  
Author(s):  
T Allgeier ◽  
W T Evans
Keyword(s):  
Electrical Resistance ◽  
Treatment Process ◽  
Force Transducer ◽  
Resistance Strain ◽  
Strain Gauges ◽  
Material Behaviour ◽  
Mechanical Hysteresis ◽  
Force Transducers ◽  
Strain Relationship ◽  
Electrical Resistance Strain

A non-linear, anelastic stress-strain relationship, hereafter called mechanical hysteresis, which leads to a significant error in the output signal of electrical resistance strain gauge force transducers, has been confirmed to be a general phenomena in precipitation-hardened stainless steels. The mechanism of mechanical hysteresis has been found to be due to the material behaviour; nevertheless, the design of the force transducer and details of the electrical resistance strain gauges could impose further minor effects on the size of the error. Some of the secondary influencing factors (for example loading and mounting details) have been eliminated in the course of the investigation. Using a specially developed heat treatment process, it has been possible to substantially reduce the hysteresis error, which in turn improves the force transducer accuracy.

High-temperature high-elongation resistance strain gauges

1969 ◽  
Vol 4 (3) ◽  
pp. 228-235 ◽  
Author(s):  
R Bertodo
Keyword(s):  
Electrical Resistance ◽  
Measurement Errors ◽  
Resistance Strain ◽  
Strain Gauges ◽  
Electrical Stability ◽  
Pertinent Data ◽  
High Elongation ◽  
Slow Cycling ◽  
High Degree ◽  
Electrical Resistance Strain

The paper outlines an investigation undertaken in an attempt to evolve an electrical-resistance strain gauge for the measurement of slowly varying strains in the range ±5 per cent over the temperature interval 20°C-400°C in oxidizing environments. A critical review of published work suggested that few pertinent data existed for plastically strained conductors and that only alloys having a high degree of electrical stability and a strain sensitivity close to 2·0 would be suitable. Two alloys appeared to possess such properties, namely one containing nearly equal molecular proportions of nickel and copper and one approximating to 4(Ni3Cr)Ni3Al. Subsequent tests on long free spcimens revealed that the electrical stability was dictated by metallurgical factors and in some way related to the fatigue ductility. Only the nickel-chromium-aluminium alloy was adequately stable, electrically and metallurgically, over the temperature range of interest, provided it was in the disordered annealed condition. Measurement errors became too high at fatigue strains above ±1·5 per cent at 400°C. Tests were carried out on flat-grid gauges with bonding media having shear strengths in excess of about 1000 lb/in2, this being the apparent limiting value for faithful transfer of strains of up to ±1·5 per cent from the specimen to the strin-sensing grid. These largely corroborated earlier tests on free specimens and suggested that strains of up to ±11/2 per cent could be detected with an error of about 10 per cent at 400°C. The zero drift amounted to an equivalent strin of 400 μin/in and this required separate correcton. The problems of temperature compensation for slow cycling rates were similar to those met in conventional steady-strain measurements with electrical-resistance strain gauges and were in no way alleviated by the high strain output available.

On the Stiffness and the Reinforcement Effect of Electrical Resistance Strain Gauges

2006 ◽  
Vol 3-4 ◽  
pp. 349-354 ◽  
Author(s):  
A. Ajovalasit ◽  
L. D'Acquisto ◽  
S. Fragapane ◽  
B. Zuccarello
Keyword(s):  
Strain Gauge ◽  
Electrical Resistance ◽  
Resistance Strain ◽  
Strain Gauges ◽  
Reinforcement Effect ◽  
Low Modulus ◽  
The Relationship ◽  
Electrical Resistance Strain

The reinforcement effect of a strain gauge installed on low modulus materials can be significant. The increasing use of low modulus materials requires therefore the evaluation of such effect. This paper concerns the relationship between the local reinforcement effect and the strain gauge stiffness. The conclusion is that the gauge stiffness alone does not allow the user a thorough evaluation of the reinforcement effect.

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