Optimization of magnetic properties of Co∕Pd multilayers by applying a large persistent biaxial stress

2007 ◽  
Vol 102 (9) ◽  
pp. 093903 ◽  
Author(s):  
Senthilnathan Mohanan ◽  
Ulrich Herr
Keyword(s):  
Magnetic Properties ◽  
Biaxial Stress

scholarly journals Damage Evaluation Using Magnetic Properties in Stainless Steels under Biaxial Stress

2008 ◽  
Vol 49 (3) ◽  
pp. 548-553 ◽  
Author(s):  
Akira Shimamoto ◽  
Hiroshi Ohkawara ◽  
Sung-mo Yang ◽  
Dae-kue Choi ◽  
Satoshi Akamatsu
Keyword(s):  
Magnetic Properties ◽  
Stainless Steels ◽  
Biaxial Stress ◽  
Damage Evaluation

Micromagnetic model for the influence of biaxial stress on hysteretic magnetic properties

1994 ◽  
Vol 75 (10) ◽  
pp. 5673-5675 ◽  
Author(s):  
M. J. Sablik ◽  
L. A. Riley ◽  
G. L. Burkhardt ◽  
H. Kwun ◽  
P. Y. Cannell ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Biaxial Stress ◽  
Hysteretic Magnetic Properties

Pig-Mounted Experimental Measurement of In-Situ Absolute Biaxial Stress in Pipelines

2008 ◽  
Author(s):  
Gordon Allan ◽  
David A. Russell ◽  
David J. Buttle ◽  
Greg Baker ◽  
John C. McCarthy
Keyword(s):  
Magnetic Properties ◽  
Biaxial Stress ◽  
Test Facility ◽  
Magnetic Response ◽  
Barkhausen Effect ◽  
Second Mode ◽  
Mode Of Operation ◽  
Bending Stresses ◽  
Recent Experimental Work

This paper describes recent experimental work on the measurement of absolute levels of biaxial stress in ferromagnetic pipeline materials. A prototype in-line inspection tool has been constructed and has subsequently undergone evaluation in a series of pigging trials to determine its accuracy in recording of stress values. Recently attention has been raised by a number of groups working on the development of techniques intended to utilize the dependence of the magnetic response of ferrous materials to applied stress in order to directly measure stress. Most of these techniques have been based on the Barkhausen effect. This paper discusses the use of an alternative technique based on other magnetic properties that have been shown to allow derivation of a quantifiable relation between the level of stress present in material and the magnetic response. This technique, named MAPS by its developers, MAPS Technology, has been employed with considerable success out-with the pipeline industry. An earlier paper described the technique used to make the measurements. The response of pipe-wall materials to an applied alternating magnetic field is measured, and knowledge of the variation of magnetic properties of the material used to determine stress values. In order to prove the suitability of this technique to pipeline applications, a prototype inspection pig has been designed and constructed, and a series of tests performed in a 24″ test facility, constructed specifically for the purpose. The test facility design allowed for two modes of operation. The first of these allowed pigging through the 50m of test pipe, with an arrangement that allowed bending stresses to be applied to the pipe. The second mode of operation enabled internal pressure to be applied as the tool was pulled through the test section. The pig based system successfully gathered stress measurements in both axial and hoop directions. The pig measurements were subsequently compared to theoretical values of stress and to measurements taken with strain gauges and other instrumentation fitted to the test facility.

In-Line In-Situ Direct Measurement of Absolute Biaxial Stress in Pipelines

2006 ◽  
Author(s):  
David A. Russell ◽  
David J. Buttle ◽  
John C. McCarthy
Keyword(s):  
Magnetic Properties ◽  
Recent Work ◽  
Pipe Wall ◽  
Rehabilitation Program ◽  
Biaxial Stress ◽  
Magnetic Response ◽  
Barkhausen Effect ◽  
Detection Techniques ◽  
Wide Range

This paper reports on recent work on the in-situ determination of absolute levels of biaxial stress in ferromagnetic pipeline materials. The response of pipe-wall materials to an applied alternating magnetic field is measured, and knowledge of the variation of magnetic properties of the material used to determine stress values. A wide variety of means are in use to detect, characterize and measure an equally wide range of defects in pipelines. These may arise from pre-existing conditions, errors in construction, effects of corrosion, accidental damage or other causes. Caliper tools, mapping tools, MFL, EMAT and ultrasonic tools are all used to detect conditions that may result in unacceptable stress in a pipeline. The ultimate aim, for all of these detection techniques, is to prove that the inspected pipeline’s fitness for purpose is maintained; and where this is not demonstrated, to provide accurate and reliable information on which to base a rehabilitation program. Recently attention has been raised by a number of groups working on the development of techniques intended to utilize the dependence of the magnetic response of ferrous materials to applied stress in order to directly measure stress. Most of these techniques have been based on the Barkhausen effect. This paper discusses the use of an alternative technique based on other magnetic properties that have been shown to allow derivation of a quantifiable relation between the level of stress present in material and the magnetic response. This technique, named MAPS by its developers, ESR Technology, has been employed with considerable success out-with the pipeline industry. Recent work has concentrated on applications in dynamic situations, in particular in pig-mounted inspection systems. A series of tests are described with dynamic measurements made inside pipes, covering measurement of applied (bending) stresses and artificially simulated defects. Measurements are described at velocities up to 4 m/s in prototype systems at 24” diameter with stand-offs of 2mm and up. Magneto-dynamic effects from the motion of the sensors past the metal of the pipe-wall have been characterized and variations in signal due to the velocity and instrument stand-off are described. It is considered that this work forms the basis for a pipeline inspection technique using these instruments.

scholarly journals Damage Evaluation Using Magnetic Properties in Stainless Steels under Biaxial Stress

2009 ◽  
Vol 73 (7) ◽  
pp. 542-547 ◽  
Author(s):  
Akira Shimamoto ◽  
Hiroshi Ohkawara ◽  
Sung-mo Yang ◽  
Dae-kue Choi ◽  
Satoshi Akamatsu
Keyword(s):  
Magnetic Properties ◽  
Stainless Steels ◽  
Biaxial Stress ◽  
Damage Evaluation
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