Effect of contributions from bending in evaluation of axial strain in rods with circular cross-section

1983 ◽  
Vol 18 (1) ◽  
pp. 77-79 ◽  
Author(s):  
L Lagerkvist ◽  
K-G Sundin ◽  
B Lundberg
Keyword(s):  
Cross Section ◽  
Axial Strain ◽  
Circular Cross Section ◽  
Strain Gauges ◽  
Elastic Rod ◽  
Simple Method ◽  
Strain Measurements ◽  
Absolute Value ◽  
Bending Strain ◽  
Good Agreement

Contributions from bending to the evaluated axial strain in an elastic rod are commonly suppressed by forming half the sum of measured surface strains at diametrically opposite positions. A simple method is presented which gives a useful estimation of the bending suppression (the ratio of the bending strain to the absolute value of the evaluated axial strain when a rod is subject to bending only) from (i) optically measured mis-positioning, and (ii) estimated differences between the gauge constants for the two strain gauges. Good agreement is obtained with results obtained from strain measurements on a rod loaded in bending.

scholarly journals Soft Elastomeric Capacitor for Angular Rotation Sensing in Steel Components

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7017
Author(s):  
Han Liu ◽  
Simon Laflamme ◽  
Jian Li ◽  
Caroline Bennett ◽  
William N. Collins ◽  
...  
Keyword(s):  
Cross Section ◽  
Steel Specimen ◽  
Element Model ◽  
Strain Gauges ◽  
Angular Rotation ◽  
Strain Measurements ◽  
Bending Strain ◽  
Hollow Structural Section ◽  
Do So ◽  
Angle Of Rotation

The authors have previously proposed corrugated soft elastomeric capacitors (cSEC) to create ultra compliant scalable strain gauges. The cSEC technology has been successfully demonstrated in engineering and biomechanical applications for in-plane strain measurements. This study extends work on the cSEC to evaluate its performance at measuring angular rotation when installed folded at the junction of two plates. The objective is to characterize the sensor’s electromechanical behavior anticipating applications to the monitoring of welded connections in steel components. To do so, an electromechanical model that maps the cSEC signal to bending strain induced by angular rotation is derived and adjusted using a validated finite element model. Given the difficulty in mapping strain measurements to rotation, an algorithm termed angular rotation index (ARI) is formulated to link measurements to angular rotation directly. Experimental work is conducted on a hollow structural section (HSS) steel specimen equipped with cSECs subjected to compression to generate angular rotations at the corners within the cross-section. Results confirm that the cSEC is capable of tracking angular rotation-induced bending strain linearly, however with accuracy levels significantly lower than found over flat configurations. Nevertheless, measurements were mapped to angular rotations using the ARI, and it was found that the ARI mapped linearly to the angle of rotation, with an accuracy of 0.416∘.

Non-Contacting Bi-Axial Strain Measurement Method on Steel Pipeline

2008 ◽  
Author(s):  
Stephen Westwood ◽  
Michael Martens ◽  
Richard Kania ◽  
David Topp ◽  
Raymond Kare´ ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Strain Measurement ◽  
Measurement Method ◽  
Axial Strain ◽  
Compressive Load ◽  
Ferromagnetic Materials ◽  
Strain Gauges ◽  
Steel Pipeline ◽  
Strain Measurements ◽  
Axial Tensile

The StressProbe is a non-contacting electromagnetic tool that responds to material strain in ferromagnetic materials. Previous studies have concentrated on uni-axial strain measurements; in this study, we extend the scope of work by measuring bi-axial strains on a pipe specimen subject to internal pressure and to a displacement-controlled, axial tensile/compressive load. Specified pressure and load combinations were obtained, and measurements from the StressProbe were compared to those from tri-axial strain gauges installed on the pipe specimen. In this paper, we present the theory behind this measurement method and the results from this study. Also discussed are measurement applications both inside and outside the pipe specimen.

Axially Symmetric Waves in Elastic Rods

1960 ◽  
Vol 27 (1) ◽  
pp. 145-151 ◽  
Author(s):  
R. D. Mindlin ◽  
H. D. McNiven
Keyword(s):  
Cross Section ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Elastic Rods ◽  
Axially Symmetric ◽  
Elastic Rod ◽  
One Dimensional ◽  
Axial Shear ◽  
Wave Numbers ◽  
Complex Wave

A system of approximate, one-dimensional equations is derived for axially symmetric motions of an elastic rod of circular cross section. The equations take into account the coupling between longitudinal, axial shear, and radial modes. The spectrum of frequencies for real, imaginary, and complex wave numbers in an infinite rod is explored in detail and compared with the analogous solution of the three-dimensional equations.

A Method to Estimate Cross-Sectional Stress Distributions on Reinforced Nozzle Corners Under Internal Pressure

2019 ◽  
Author(s):  
Chang-Sik Oh ◽  
Tae-Kwang Song ◽  
Sang-Min Lee
Keyword(s):  
Internal Pressure ◽  
Cross Section ◽  
Pressure Vessels ◽  
Fe Analysis ◽  
Stress Distributions ◽  
Corner Crack ◽  
Cross Sectional ◽  
Simple Method ◽  
Geometric Variables ◽  
Good Agreement

Abstract Stress distribution through the nozzle corner cross-section may be required to calculate stress intensity factor (SIF) for a nozzle corner crack in accordance with ASME Section XI Nonmandatory Appendix G. This paper proposes a simple method to predict nozzle corner cross-section stress distributions on reinforced nozzle corners of pressure vessels under internal pressure. This method includes simplified equations for predicting stresses on the inner surfaces of the nozzle corner region. These equations are expressed in terms of stress concentration factor (SCF) and geometric variables. Approximate SCF solutions for the reinforced nozzle corners are also proposed. Stress distributions using the proposed method are compared with finite element (FE) analysis results of nozzle-vessel intersections of various geometric dimensions, and agreements are quite good within postulated crack depths. Furthermore, SIFs calculated from the estimated stress distributions in accordance with ASME Section XI Nonmandatory Appendix G are compared with those from the FE results, showing good agreement.

Rise in optimized capillary channels

2013 ◽  
Vol 731 ◽  
pp. 142-161 ◽  
Author(s):  
B. Figliuzzi ◽  
C. R. Buie
Keyword(s):  
Cross Section ◽  
Silicone Oil ◽  
Capillary Rise ◽  
Circular Cross Section ◽  
Heat Pipes ◽  
Design And Optimization ◽  
The Subject ◽  
Micro Heat Pipes ◽  
Good Agreement ◽  
Optimal Radius

AbstractMany technological applications rely on the phenomenon of wicking flow induced by capillarity. However, despite a continuing interest in the subject, the influence of the capillary geometry on the wicking dynamics remains underexploited. In numerous applications, the ability to promote wicking in a capillary is a key issue. In this article, a model describing the capillary rise of a liquid in a capillary of varying circular cross-section is presented. The wicking dynamics is described by an ordinary differential equation with a term dependent upon the shape of the capillary channel. Using optimal control theory, we were able to design optimized capillaries which promote faster wicking than uniform cylinders. Numerical simulations show that the height of the rising liquid was up to 50 % greater with the optimized shapes than with a uniform cylinder of optimal radius. Experiments on specially designed capillaries with silicone oil show a good agreement with the theory. The methods presented can be useful in the design and optimization of systems employing capillary-driven transport including micro-heat pipes or oil extracting devices.

scholarly journals Efficiency of Hysteresis Rods in Small Spacecraft Attitude Stabilization

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Assal Farrahi ◽  
Ángel Sanz-Andrés
Keyword(s):  
Thin Film ◽  
Cross Section ◽  
Circular Cross Section ◽  
Semiempirical Method ◽  
Spacecraft Attitude ◽  
Flight Data ◽  
Small Satellites ◽  
Attitude Stabilization ◽  
Section Shape ◽  
Good Agreement

A semiempirical method for predicting the damping efficiency of hysteresis rods on-board small satellites is presented. It is based on the evaluation of dissipating energy variation of different ferromagnetic materials for two different rod shapes: thin film and circular cross-section rods, as a function of their elongation. Based on this formulation, an optimum design considering the size of hysteresis rods, their cross section shape, and layout has been proposed. Finally, the formulation developed was applied to the case of four existing small satellites, whose corresponding in-flight data are published. A good agreement between the estimated rotational speed decay time and the in-flight data has been observed.

Spirally bound concrete columns

1985 ◽  
Vol 400 (1818) ◽  
pp. 127-144 ◽  
Keyword(s):  
Cross Section ◽  
Material Properties ◽  
Circular Cross Section ◽  
Plain Concrete ◽  
Concrete Columns ◽  
Stress Strain Relation ◽  
Mathematical Expressions ◽  
Iterative Procedures ◽  
Theoretical Results ◽  
Good Agreement

In this paper, mathematical expressions for the material properties of plain concrete are used in conjunction with the stress–strain relation of steel reinforcement to develop equations for both the strength and deformational behaviour of axially loaded concrete columns of circular cross section and with closely spaced spiral binding. Iterative procedures are used to solve these equations and the theoretical results are shown to be in good agreement with experimental results obtained by earlier investigators.

On the deflected configuration of a slender elastic rod subject to parallel terminal forces and moments

1995 ◽  
Vol 449 (1936) ◽  
pp. 337-349 ◽  
Keyword(s):  
Cross Section ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Cartesian Coordinate System ◽  
Elastic Rod ◽  
Equilibrium Equations ◽  
Elastic Deformations ◽  
Nonlinear Equilibrium ◽  
Cartesian Coordinate ◽  
Nonlinear Elastic

This paper investigates the three-dimensional configurations of a slender elastic rod of uniform circular cross-section subject to parallel terminal forces and moments. The nonlinear, equilibrium equations for the rod are established for a Cartesian coordinate system and solved analytically without linearization. Consequently, the results are applicable for large nonlinear elastic deformations.

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