Nondestructive Testing and Structural Condition Monitoring of Mechanical Cables

1993 ◽  
Vol 46 (4) ◽  
pp. 133-138 ◽  
Author(s):  
Patricio A. A. Laura

This article concerns the problem of evaluating the `structural health’ of cables or ropes by means of non-destructive testing methods. Special emphasis is placed upon electromagnetic techniques and the acoustic emission method.

2012 ◽  
Vol 229-231 ◽  
pp. 1476-1480 ◽  
Author(s):  
Salah M. Ali Al-Obaidi ◽  
M. Salman Leong ◽  
R.I. Raja Hamzah ◽  
Ahmed M. Abdelrhman

Acoustic emission (AE) measurements are one of many non-destructive testing methods which had found applications in defects detection in machines. This paper reviews the state of the art in AE based condition monitoring with particular emphasis on rotating and reciprocating machinery applications. Advantages and limitations of the AE technique in comparison to other condition monitoring techniques in detecting common machinery faults are also discussed.


CORROSION ◽  
1976 ◽  
Vol 32 (4) ◽  
pp. 121-126 ◽  
Author(s):  
T. W. RETTIG ◽  
M. J. FELSEN

Abstract There is a continuing need for new test techniques to follow corrosion reaction processes and to predict long-term materials performance in aggressive environments. Additionally, there is a growing awareness of the importance of applying non-destructive inspection to determine the presence of corrosion in non-visible areas of equipment and structures. The possibilities of utilizing acoustic emission for a broad range of applications in the study of these problems were explored. Proprietary methods were developed to follow corrosion reactions and to monitor corrosion of simulated and actual structures. These experiments point out the applicability of acoustic emission as a sensitive new tool for corrosion research and non-destructive testing (NDT) in corrosion prone structures and equipment.


This article discusses the problems of the acoustic emission method of non-destructive testing. An approach to filtering noise arising from monitoring of acoustic emission is considered. The filtering of acoustic noise is one of the key problems of the acoustic emission method, since the low noise immunity of the acoustic emission method prevents the expansion of its industrial application. The complexity of the filtering is explained by the fact that the waveform and spectrum of acoustic emission pulses change depending on the distance between the defect, which is the source of acoustic emission waves, and the sensor. In turn, the interference, as a rule, is non-stationary in nature and is determined by the type of technological process of the tested composition. This article discusses various types of noise processes, both stationary and non-stationary. The signal and noise parameters are compared, based on which recommendations are given for constructing algorithms for detecting acoustic emission pulses against a background of noise.


2013 ◽  
Vol 592-593 ◽  
pp. 553-556
Author(s):  
František Vlasic ◽  
Josef Volák ◽  
Libor Nohál ◽  
Pavel Mazal ◽  
Filip Hort

This paper deals with the basic research of cyclic damage during the initial stages of fatigue process using the non-destructive testing methods. The acoustic emission method was used for monitoring of the microstructure changes during fatigue loading. The electrical potential measurements of specimen and microscopic observation were used mainly to detect the first short cracks and their propagation. The fatigue tests at room temperature were conducted on titanium alloy and creep-resistant steel specimens under bending and tension loading. The aim of the study was to compare the acoustic emission signal at different types of loading until fracture and to analyze in detail the signal changes in initial stages of fatigue process. This analysis was primarily based on the waveform similarity and division into classes. The results show the high sensitivity of the acoustic emission technology in the transition from the stage of surface relief evolution to the stage of crack nucleation and propagation.


Author(s):  
Олег Игоревич Колесников ◽  
Евгений Евгеньевич Зорин ◽  
Алексей Викторович Гейт ◽  
Игорь Игоревич Михайлов ◽  
Петр Сергеевич Голосов

Внутритрубная диагностика позволяет обеспечить высокую выявляемость поверхностных трещиноподобных дефектов стенки трубопровода. Для их устранения в условиях проведения ремонтных работ на подводных переходах магистральных нефте- и нефтепродуктопроводов традиционно используется установка герметизирующей камеры, изолирующей дефектный участок и позволяющей в полной мере провести обследование области с опасным дефектом и дальнейший ремонт с применением методов неразрушающего контроля. Данная технология является безальтернативной, когда требуется вырезка-вварка катушки или другая сварочно-монтажная операция, однако представляется избыточной для устранения поверхностного дефекта методом вышлифовки. Современные технологии позволяют устранить поверхностный трещиноподобный дефект без установки герметизирующей камеры и тем самым значительно уменьшить трудоемкость и стоимость ремонта. Однако их широкое применение сдерживается отсутствием технической возможности проведения контроля качества отремонтированного участка под водой методами неразрушающего контроля с эквивалентной чувствительностью и выявляемостью относительно обычных условий. В этой связи выполнены экспериментальные исследования с целью определения пороговых значений параметров поверхностных трещиноподобных дефектов, выявляемых методами неразрушающего контроля в подводных условиях с учетом качества зашлифованной поверхности. Такие значения получены, в частности, для метода ультразвукового контроля с технологией фазированной решетки, модуляционного метода контроля с использованием вихретоковой матрицы, люминесцентного магнитопорошкового метода. Сформулированы требования к характеристикам оборудования для проведения неразрушающего контроля в условиях подводных работ. In-line diagnostics makes it possible to secure high detectability of surface crack-like defects of the pipeline wall. To eliminate them in conditions of repair work performed on submerge crossings of main oil and oil products pipelines, the installation of a sealing chamber is traditionally used to isolate the defective area and to enable a full-investigation of the area with a hazardous defect and further repairs, by non-destructive testing methods. This technology has no alternatives when cutting and welding of the coil or other welding and assembly operation is required, but it seems redundant for elimination of a surface defect by grinding method. Modern technologies make it possible to eliminate a surface crack-like defect without installing a sealing chamber and thereby can substantially cut manpower input and cost of repair. Their widespread use is deterred by the lack of technical possibility for quality control of the repaired area under water by nondestructive testing methods with equivalent sensitivity and detectability versus the normal conditions. In this regard, experimental research has been conducted to determine the threshold values of the parameters of surface crack-like defects detected by non-destructive testing methods in submerged conditions, taking into account the quality of the sanded surface. Such values were obtained, in particular, for the ultrasonic testing method with phased array technology, the modulation control technique using eddy current matrix, and the luminescent magnetic powder method. Requirements to performance characteristics of equipment for nondestructive testing in submerged operations have been formulated.


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