The diversity of ultrasound techniques used in oil and gas pipeline plants provides us with a wealth of information on how to exploit this technology when combined with other techniques, in order to improve the quality of analysis. The fundamental theory of ultrasonic nondestructive evaluation (NDE) technology is offered, along with practical limitations as related to two factors (wave types and transducers). The focus is limited to the two main techniques used in pipe plants: First, straight beam evaluation and second, angle beam evaluation. The depth of defect (DD) is calculated using straight beam ultrasonic in six different materials according to their relative longitudinal wave (LW) velocities. The materials and respective velocities of LW are: rolled aluminum (6420 m/s), mild steel (5960 m/s), stainless steel-347 (5790 m/s), rolled copper (5010 m/s), annealed copper (4760 m/s), and brass (4700 m/s). In each material eight defects are modeled; the first represents l00% of the material thickness (D), 50.8 mm. The other seven cases represent the DD, as 87.5% of the material thickness, 75%, 62.5%, 50%, 37.5%, 25%, and 12.5%, respectively. Using angle beam evaluation, several parameters are calculated for six different reflection angles (βR) (45˚, 50˚, 55˚, 60˚, 65˚ and 70˚). The surface distance (SD), ½ skip distance (SKD), full SKD, and 1 ½ SKD, ½ sound path (SP) length, full SP, and 1 ½ SP are calculated for each βR. The relationship of SKD and SP to the βR is graphed. A chief limitation is noted that ultrasound testing is heavily dependent on the expertise of the operator, and because the reading of the outcome is subjective, precision may be hard to achieve. This review also clarifies and discusses the options used in solving the industrial engineering problem, with a comprehensive historical summary of the information available in the literature. Merging various NDE inspection techniques into the testing of objects is discussed. Eventually, it is hoped to find a suitable technique combined with ultrasonic inspection to deliver highly effective remote testing.
This research investigates the application of microwave nondestructive testing (NDT) to oil and gas pipe wall reductions (PWR) in manufacturing that are less than full-circumferential in extent. Pipes were modeled using Computer Simulation Technology (CST) simulation software, CST Microwave Studio holding pipe length, wall thickness, depth of PWR and configuration constant. The study looks at 32 models in order to determine sweeping frequency limitations for full-circumferential, half-circumferential, three-quarter-circumferential and quarter-circumferential extents of PWR with 8 widths ranging from 6.35mm to 50.8mm. The limitations were determined to be between the extremes. The 6.35mm width did not cause a resonance peak even with a full-circumferential PWR. The 50.8mm width produced a detectible resonance peak, but it is within the range established by the six middle widths.
Research using microwaves (MWs) to detect pipe wall thinning (PWT) distinguishes the presence of wall thinning, but does not accurately locate the discontinuities. Ultrasonic testing (UT) is capable of accurately locating the PWT defect, but cannot do so without time-consuming linear scanning. This novel work combines the MW technique as a way to predict the location of a series of PWT specimens, and the UT technique as a way to characterize the PWT specimens in terms of location, depth, and profile shape. The UT probe is guided to the predicted location derived from the Phase One MW results, generating the Phase Two results to determine accurate location, depth measurement, and profile shape detection. The work uses the previously successful experimental setup for testing of an aluminum pipe with 154.051 mm inner diameter (ID) and 1 m length. A vector network analyzer (VNA) generates a MW sweeping frequency range of 1.4–2.3 GHz. This signal is propagated within reference pipes with both open end and short-circuit configurations for calibration of the system. The calibrated system is used to detect the presence and location of six PWT specimens, with two profile shapes, at three depths of thinning and three locations along the pipe. The predicted locations from Phase One are then used to guide a calibrated, manually guided straight beam UT probe to the predicted position. From that point, the UT probe is used in order to accurately localize and determine the depth and shape profile of the specimens.
Agent based simulation has successfully been applied to model complex organizational behavior and to improve or optimize aspects of organizational performance. Agents, with intelligence supported through the application of a genetic algorithm are proposed as a means of optimizing the performance of the system being modeled. Local decisions made by agents and other system variables are placed in the genetic encoding. This allows local agents to positively impact high level system performance. A simple, but non trivial, peg game is utilized to introduce the concept. A multiple objective bin packing problem is then solved to demonstrate the potential of the approach in meeting a number of high level goals. The methodology allows not only for a systems level optimization, but also provides data which can be analyzed to determine what constitutes effective agent behavior.
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