One of the largest movers of the world economy is the oil and gas industry. The industry generates billions of barrels of oil to match more than half the world’s energy demands. Production of energ...

https://journals.sagepub.com/doi/pdf/10.1177/1475921719837718

Inspection and monitoring systems subsea pipelines: A review paper:

Summary
Guided waves find their niche in cost-effective damage identification in comparison with conventional nondestructive evaluation. Comprehensive research has been conducted since the 1980s, focusing on the detection of a wide variety of types of damage in metallic and composite structures. The main scope of this paper is to present a review of state-of-the-art guided wave-based approaches for damage identification in pipeline structures. Theoretical analyses of the interaction between linear and nonlinear guided waves and damage are addressed in detail. Numerical simulations and experimental studies of damage identification in pipeline structures using both linear and nonlinear guided waves are elaborated. Other issues including bends in pipes, effects of environmental and operational conditions on the performance of guided waves are another focus of this review. Future challenge in this field is summarised at the end of this review.

Guided waves for damage identification in pipeline structures: A review

The design of a novel mother wavelet that is tailor-made for continuous wavelet transform in extracting defect-related features from reflected guided wave signals

This paper investigates the reflection of the torsional T(0,1) mode from defects in pipe bends. The effect of varying circumferential and angular position along the pipe bend, as well as the influence of the bend radius, is investigated via 3D finite element simulations. The results show that the reflection expected from a small defect varies significantly with position, the minimum reflection coefficient being about 10% of that from a comparable defect in a straight pipe, while maxima of around four times the straight pipe value are seen. The areas of low detectability are mainly found on the bend intrados and those of high detectability close to its extrados; similar effects are seen in bends with radii varying from one to twenty pipe diameters. It is shown that the reflection from a defect at a given location is roughly proportional to the square of the von Mises stress produced by the transmitted wave at that position. This holds for defects such as circumferential cracks, the detailed subject of this investigation, and is also expected to be valid for corrosion patches; it will not hold for axial cracks. The results explain the low reflection seen from a simulated corrosion defect at a bend in a previous investigation.

Reflection of torsional T(0,1) guided waves from defects in pipe bends

Elevator wire ropes with polymer cores hold and hoist heavy fluctuating loads in a corrosive environment. Such working condition causes metal fatigue, which together with abrasion around pulleys le...

Detection of broken wires in elevator wire ropes with ultrasonic guided waves and tone-burst wavelet:

Interaction of low-frequency axisymmetric ultrasonic guided waves with bends in pipes of arbitrary bend angle and general bend radius.

Ultrasonic guided waves in hollow cylinders (pipes) are today widely applied as rapid screening tools in the inspection of straight pipe segments in oil, power generation and petrochemical processing industries. However, the characteristics of guided wave propagation across features such as bends in the pipe network are complicated, hampering a wider application of the developed techniques. Although a growing number of studies in recent years have considered guided wave propagation across elbows and U-type bends, the topic is still not very well understood for a general bend angle φ, mean bend radius R and pipe thickness b. Here we use 3D Finite Element (FE) simulation to illumine the propagation of fundamental guided pipe modes across bends of several different angles φ. Two different bend radius regimes, R/λ ≈ 1 and 10 (where λ denotes the wavelength of the mode studied) are considered, exemplifying 'sharp' and gradual or 'slow' bends. Different typical pipe thicknesses b within these regimes are also s...

Studies on the influence of axial bends on ultrasonic guided waves in hollow cylinders (pipes)

Abstract Additive manufacturing (AM) technologies have been recognized for their capability to build complex components and hence have offered more freedom to designers for a long time. The ability to directly use a computer-aided design (CAD) model has allowed for fabricating and realizing complicated components, monolithic design, reducing the number of components in an assembly, decreasing time to market, and adding performance or comfort-enhancing functionalities. One of the features that can be introduced for boosting a component functionality using AM is the inclusion of surface texture on a given component. This inclusion is usually a difficult task as creating a CAD model resolving fine details of a given texture is difficult even using commercial software packages. This paper develops a methodology to include texture directly on the CAD model of a target surface using a patch-based sampling texture synthesis algorithm, which can be manufactured using AM. Input for the texture generation algorithm can be either a physical sample or an image with heightmap information. The heightmap information from a physical sample can be obtained by 3D scanning the sample and using the information from the acquired point cloud. After obtaining the required inputs, the patches are sampled for texture generation according to non-parametric estimation of the local conditional Markov random field (MRF) density function, which helps avoid mismatched features across the patch boundaries. While generating the texture, a design constraint to ensure AM producibility is considered, which is essential when manufacturing a component using, e.g., Fused Deposition Melting (FDM) or Laser Powder Bed Fusion (LPBF). The generated texture is then mapped onto the surface using the developed distance and angle preserving mapping algorithms. The implemented algorithms can be used to map the generated texture onto a mathematically defined surface. This paper maps the textures onto flat, curved, and sinusoidal surfaces for illustration. After the texture mapping, a stereolithography (STL) model is generated with the desired texture on the target surface. The generated STL model is printed using FDM technology as a final step. 

/pdf/development-of-texture-mapping-approaches-for-additively-2bv2kpqo.pdf

Development of Texture Mapping Approaches for Additively Manufacturable Surfaces


 Presence of surface breaking cracks on engineering structures such as rails, pressure vessels, turbine blades or pipelines affect the service life. Moreover, if the depth of such cracks is not known, then these parts are typically subjected to direct rejection. Economically this is highly expensive as it can cause the complete disruption of the service. Having an accurate knowledge of crack depth can be used in fracture mechanics analysis to estimate the remaining life of the structure. Among the available nondestructive testing (NDT) techniques, eddy current testing (ECT) is the most widely used method for the detection and sizing of such cracks due to their high sensitivity to surface and near surface defects. However, the size of surface cracks in length and depth requires a complex calibration. Moreover, the depth range is limited by the penetration depth of eddy current. Ultrasonic Rayleigh waves are recently attracting interest for the detection and characterization of surface cracks. The advantages include length and depth sizing as well as the possibility to scan a relatively large area from a limited number of probe positions. The generation of Rayleigh waves can be achieved using piezoelectric transducer, electromagnetic acoustic transducers, air-coupled transducer or laser ultrasound. A considerable research interest on the detection and sizing of surface crack using laser generated Rayleigh waves, has been observed. However, this technique requires extra safety from the users, may require surface preparation and the cost of the equipment is prohibitive. This work presents a method to measure the depth of surface breaking electrical discharged machined (EDM) notches using Rayleigh waves excited and received through conventional ultrasonic phased array probes. Here, the generation of Rayleigh waves is achieved through appropriate delay between the emission of each piezoelectric element of the phased array probe. The time-of-flight (TOF) information of Rayleigh waves and their interaction with the geometry of the notches can be used to size its depth. A two-dimensional finite element (FE) model was used to demonstrate the proposed sizing method. Results obtained from FE simulations show excellent agreement between the measured and simulated true notch depth.

Bhupesh Verma

Papers

Interaction of low-frequency axisymmetric ultrasonic guided waves with bends in pipes of arbitrary bend angle and general bend radius.

Studies on the influence of axial bends on ultrasonic guided waves in hollow cylinders (pipes)

Development of Texture Mapping Approaches for Additively Manufacturable Surfaces

Surface Crack Sizing Method Using Rayleigh Waves Generated by Ultrasonic Phased Arrays

An Alternative Rayleigh Wave Excitation Method Using an Ultrasonic Phased Array