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PRCI PR-15-9922
- Development of Fieldable Magnet and Digital MIVC Stress Measurement Techniques
- Report / Survey by Pipeline Research Council International, 04/01/2002
- Publisher: PRCI
$48.00$95.00
L52011e
Southwest Research Institute
Need: A nondestructive evaluation (NDE) technique and instrument were needed to measure pipeline stresses in the field. The technique must measure the average through-wall biaxial stress in an excavated section of an operating pipeline. Furthermore, the instrument must be portable and easily operated by a single field technician. Equipped with such an instrument, service crews could evaluate the structural integrity of a line, determine if remedial actions need to be taken for prevention of stress related damage, or determine whether a line that is to be cut represents a potential safety problem due to "springing" from residual stresses. One technique that has been identified as a potential technology for the measurement of stresses in pipeline is the magnetically induced velocity change (MIVC) method.
Benefit: The objective of this project was to start the process of making the MIVC technique simple and cost effective for use in the field by reducing both the size of the required sensors and instrumentation and the calibration requirements. Three steps were taken to meet this objective: (1) design and build a small, lightweight magnetic circuit that can be handled by a single technician, (2) reduce the number and size of the instruments used to perform the MIVC measurements, and (3) investigate the variability of the MIVC calibration curves among different pipe grades and the feasibility of establishing a universal calibration curve or family of curves.
Result: The objective of this project was to produce (1) an easily transportable magnetic circuit suitable for field use, (2) a digital technique for measurement of the MIVC (in a more portable form), and (3) the feasibility of defining a set of calibration curves which apply to the majority of high grade pipes. The first objective was met with complete success. The second objective is incomplete due to problems with noise that were not anticipated. The second objective is incomplete due to problems with noise that were not anticipated. The third objective has been met.
Southwest Research Institute
Need: A nondestructive evaluation (NDE) technique and instrument were needed to measure pipeline stresses in the field. The technique must measure the average through-wall biaxial stress in an excavated section of an operating pipeline. Furthermore, the instrument must be portable and easily operated by a single field technician. Equipped with such an instrument, service crews could evaluate the structural integrity of a line, determine if remedial actions need to be taken for prevention of stress related damage, or determine whether a line that is to be cut represents a potential safety problem due to "springing" from residual stresses. One technique that has been identified as a potential technology for the measurement of stresses in pipeline is the magnetically induced velocity change (MIVC) method.
Benefit: The objective of this project was to start the process of making the MIVC technique simple and cost effective for use in the field by reducing both the size of the required sensors and instrumentation and the calibration requirements. Three steps were taken to meet this objective: (1) design and build a small, lightweight magnetic circuit that can be handled by a single technician, (2) reduce the number and size of the instruments used to perform the MIVC measurements, and (3) investigate the variability of the MIVC calibration curves among different pipe grades and the feasibility of establishing a universal calibration curve or family of curves.
Result: The objective of this project was to produce (1) an easily transportable magnetic circuit suitable for field use, (2) a digital technique for measurement of the MIVC (in a more portable form), and (3) the feasibility of defining a set of calibration curves which apply to the majority of high grade pipes. The first objective was met with complete success. The second objective is incomplete due to problems with noise that were not anticipated. The second objective is incomplete due to problems with noise that were not anticipated. The third objective has been met.