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.

scholarly journals Tension and Compression Behaviour of Fly Ash-Lime-Gypsum Composite Mixed with Treated Tyre Chips

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
S. P. Guleria ◽  
R. K. Dutta
Keyword(s):  
Fly Ash ◽  
Axial Strain ◽  
Compressive Load ◽  
Tensile Load ◽  
Constructional Material ◽  
Toughness Index ◽  
Road Pavement ◽  
Curing Period ◽  
Axial Tensile ◽  
Tension And Compression

This paper presents the results of effect of inclusion of water, sodium hydroxide and carbon tetrachloride treated tire chips on Compressive load, tensile load, axial strain, diametral strain, toughness index and post peak behaviour of the reference mix containing fly ash + 8% lime + 0.9% gypsum for a curing period varying from 7 to 180 days using three different curing methods. The results of this study revealed that the axial/diametral strain, axial/tensile load of reference mix mixed with dry tyre chip can be increased with the treatment provided on dry tyre chips. The axial/diametral strain, axial/tensile load, toughness index improves with the change in curing method and curing period. Potential use of this relatively new constructional material can be road pavement having light traffic.

In Line Inspection of Geotechnical Hazards

2014 ◽  
Author(s):  
Stephen Westwood ◽  
Dan Jungwirth ◽  
Randy Nickle ◽  
Doug Dewar ◽  
Michael Martens
Keyword(s):  
Technology Implementation ◽  
Strain Measurement ◽  
Axial Strain ◽  
Steel Structure ◽  
Total Strain ◽  
Electromagnetic Properties ◽  
Strain Gauges ◽  
Measurement Tool ◽  
Survey Tool

Four North American pipeline operators and a pipeline inspection company have been working together on a research project assessing the feasibility of using an electromagnetic non-contacting strain measurement tool capable of being deployed during ILI inspection to measure axial strain in pipelines. The axial strain sensor is the TSC StressProbe. It is an electromagnetic technique which makes use of the fact that when a steel structure is loaded, its electromagnetic properties change. Monitoring the changes in magnetic properties allows one to measure changes in strain. The use of in-line inspection high resolution inertial survey tool data in the determination of bending strain in operating pipelines is well developed and understood. The missing component in determining the total strain in the pipeline is to understand the component of axial strain that the pipeline is experiencing without the need to expose the pipeline for the installation of surficial pipe monitoring (primarily strain gauges) or destructive testing (such as cut-outs). Many current methods of stress/strain measurement including the installation of strain gauges only allows for the determination of change in strain going forward from the date of install; whereas, the StressProbe responds to total strain at the time of inspection. This paper will present the technology implementation, inspection feasibility and discuss preliminary results from case studies in determining the ability of the in-line inspection axial strain measurement to correlate with known changes in strain in pipelines being influenced by ground movements.

Strain Relief of a Buried Pipeline Due to Slope Movement

2008 ◽  
Author(s):  
Michael Martens ◽  
Richard Kania ◽  
Raymond Kare ◽  
David Topp ◽  
Frank Sander
Keyword(s):  
Ferromagnetic Materials ◽  
Slope Movement ◽  
Strain Gauges ◽  
Buried Pipeline ◽  
Strain Relief ◽  
Strain Measurements ◽  
Over Time ◽  
Surrounding Soil

Pipelines constructed through geologically active areas, over time, can experience a significant amount of strain due to slope movement. Eventually may become necessary to strain relief the pipeline to ensure its integrity, which is the removal of the surrounding soil to allow for relaxation of the pipeline. This paper looks at the issue of pipeline strain relief due to gradual slope movement and quantifying the amount of relaxation. A non-contacting electromagnetic tool, the TSC StressProbe, that responds to material strain in ferromagnetic materials and a series of strain gauges were used to take in-situ pipeline strain measurements during the strain relieving excavation.

scholarly journals A Modified Algorithm for Reducing Calculation Errors in Large Strain Measurement with Strain Gauges

2008 ◽  
Vol 13-14 ◽  
pp. 261-268
Author(s):  
Gang Chen ◽  
Y. Deng ◽  
Liang Sun ◽  
T. Xu
Keyword(s):  
Strain Measurement ◽  
Large Strain ◽  
Experimental Tests ◽  
Small Strain ◽  
Strain Gauges ◽  
Lead Wire ◽  
Strain Measurements ◽  
Measured Voltage ◽  
Wire Resistance ◽  
Modified Algorithm

There is no simple linear relationship between strain and potential in strain measurement with strain gauges, especially for large strain measurements. In this paper, a modified algorithm was proposed to improve the accuracy of strain obtained from measured voltage. The strain was calculated from a nonlinear relationship between voltage and strain rather than a linear simplification. Moreover, the corrections for different sensitivity factors of strain gauges and lead wire resistance were considered. The proposed method was suitable for both large and small strain measurements using a quarter bridge, and validated by experimental tests. It is also very easy to be implemented as a software form and used in scientific tests and engineering applications.

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.

Tensile Strain Capacity of Pipelines for Strain-Based Design

2008 ◽  
Author(s):  
Bing Liu ◽  
X. J. Liu ◽  
Hong Zhang
Keyword(s):  
Finite Element ◽  
Quantitative Determination ◽  
Internal Pressure ◽  
Tensile Strain ◽  
Surface Defects ◽  
Axial Strain ◽  
Finite Element Analyses ◽  
Axial Tensile ◽  
Strain Limit

Traditional pipeline design methods presented in various codes are usually based on limit stress criteria. However, these methods may be inapposite to modern steels, especially for displacement controlled loads such as ground displacement load. The design of pipelines for plastic strain should account for both tension strain limit and compression strain limit along the axial direction of the pipe. In tension, the issues relate to the failure modes of plastic collapse or fracture. Tensile axial strain of the pipe often results in rupturing. The capacity of tensile axial strain of the pipe is affected by a large number of factors: D/t ratio, Y/T ratio, internal pressure, girth weld effect, and defect size and location. Consequently, full solutions for tensile strain limits related to above-mentioned factors do not yet exist in codes and standards. In recent years, a number of projects have been funded to develop a quantitative determination of tensile strain limits in China. This paper covers the technical basis of the procedures. The development of the quantitative approach to tensile strain limits involves both experimental tests and finite element analyses, and the process is as follows. Firstly, a series of curved wide plate tests under the axial tensile strain have been done, especially including more than 60 girth weld specimens with not only buried or surface defects but also various defect-sizes and defect-locations. Based on these test data and other available experiment data of full scale tests under the axial tensile strain and internal pressure loading, a valid finite element model has been found. Then a total of 110 finite element analyses produced a lot of data for a wide range of material, D/T ratios, various defect sizes or locations, buried or surface defects, and various internal pressures. So some parametric equations can be developed from finite element analyses. The safety factors and appropriate limits for the parametric equations have been identified against much more experimental data. It is believed that the approach to axial tensile strain limit presented in this paper may lay the initial basis for the quantitative determination of tensile strain limits to pipelines.

Axial Strains in FRP-Confined Normal- and High-Strength Concrete: An Examination of Strain Measurement Methods

2014 ◽  
Vol 919-921 ◽  
pp. 23-28 ◽  
Author(s):  
Thomas Vincent ◽  
Togay Ozbakkloglu
Keyword(s):  
Cross Sections ◽  
Strain Measurement ◽  
High Strength Concrete ◽  
Measurement Method ◽  
Axial Strain ◽  
High Strength ◽  
Measurement Methods ◽  
Strength Concrete ◽  
Highly Sensitive ◽  
Variable Displacement

This paper presents an experimental investigation into the axial strain measurement method of fiber reinforced polymer (FRP)-confined normal-and high-strength concrete (NSC and HSC). A total of 15 FRP-confined concrete specimens with circular cross-sections were tested under monotonic axial compression. Axial strain recordings were compared on specimens instrumented with three different measurement methods: axial strain gauges and full-and mid-height linear variable displacement transformers (LVDTs). The ultimate conditions are tabulated for each measurement method and key experimental outcomes discussed. The results indicate that axial strains of FRP-confined HSC are highly sensitive to the instrumentation arrangement and significant differences occur in the results obtained from different measurement methods.

Traceability of Optical Techniques for Strain Measurement

2006 ◽  
Vol 3-4 ◽  
pp. 391-396 ◽  
Author(s):  
Erwin Hack ◽  
Richard L. Burguete ◽  
E.A. Patterson
Keyword(s):  
Reference Materials ◽  
Strain Measurement ◽  
Optical Methods ◽  
Strain Gauges ◽  
Unified Approach ◽  
Dimensionless Quantity ◽  
Strain Measurements ◽  
Optical Strain Measurement ◽  
Optical Strain

Strain is a dimensionless quantity derived from displacement. To measure strain, devices such as resistive strain gauges and extensometers but also imaging methods are applied in engineering and experimental mechanics. The lack of standards and reference materials related to optical methods of strain measurement is tackled by the SPOTS project. It is intended to make full use of the modularity of different methods in order to develop a unified approach to standardisation. In this contribution we focus on the problem of traceability of optical strain measurement values and underline the role of strain measurement standards. We clarify the terminology and outline routes for traceability in analogy to widespread procedures for single value strain measurements.

Sign in / Sign up

Export Citation Format

Share Document