Offshore oil and gas platforms present a harsh environment for their installed infrastructure, with pipelines that are subjected to both a corrosive atmosphere and transport of aggressive chemicals being the most critical. These conditions have prompted the industry to substitute metallic pipelines for composite counterparts, often made from fiber-reinforced plastics assembled with bonded joints. Various technologies have emerged in recent years to assess the health of these composite pipelines. In particular, robust speckle metrology techniques such as shearography, although not capable of long-term monitoring, have produced very satisfactory results. However, these inspection techniques require specialized equipment and trained personnel to be flown to offshore platforms, which can incur in non-trivial inspection costs. In this paper, we propose and demonstrate a robust and cost-effective approach to monitor pipeline bonded joints during assembly and operation using fiber Bragg grating (FBG) sensors embedded into the joints’ adhesive layer. This approach allows for informed decisions on when to perform targeted in-depth inspections (e.g., with shearography) based on both real-time and long-term feedback of the FBG sensors data, resulting in lower monitoring costs, a severe increase in monitoring uptime (up to full uptime), and increased operational security.
In recent years, a great effort has been done to improve damage detection techniques in structures by using vibration measurements. This paper presents a case where a non-contact measurement system, a Scanning Laser Doppler Vibrometer, has been used to detect delaminations in a composite material plate. The diagnostic technique is the evolution of a methodology previously approached by the authors. An in-house made software has been produced for data acquisition and vibrometer control. The maps ofthe detected defects are presented, thus allowing the assessment of the performances of this methodology to detect damages. This analysis permitted to outline the main points to be improved in the future investigations.
This paper presents a new approach to improve the quality of shearographic phase maps acquired in a harsh environment. During in-field nondestructive inspections, the presence of higher disturbances, mainly vibrations, can introduce unknown phase deviations in the sequence of shearographic images. This paper presents a different approach that combines the N-dimensional Lissajous algorithm [Int. J. Optomechatron.8, 340 (2014)1559-961210.1080/15599612.2014.942933] and the concept of phase of differences [Proc. SPIE6345, 634510 (2006)PSISDG0277-786X10.1117/12.693149] to improve the quality of phase maps. The concept is compared with two other methods. Results, advantages, and difficulties of each method are also presented and discussed by using real fringe maps.
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