Carbon Fiber Reinforced Polymer (CFRP) considered as unique material as it is proven have the best mechanical properties which can be used as a wrapping. This composite material will be evaluated as a wrapping material using SolidWork version 2021 software. Elbow has been chosen as component to be wrapped as it is one of the most critical parts in a pipeline system. Thus, this research focuses on 90-degree butt welded elbows. The study evaluated different lamination and thickness of CFRP as a wrapping framework for elbows. Static analysis also was stimulated to analyze the stress and strain exerted on elbows at extrados location. Based on static analysis simulation from SolidWork software, lamination orientation of (0º) with 6 layers exhibit lowest stress for all the pressure tested ranging from 0.86MPa to 19.65MPa for 90-degree defected elbow at extrados location. Besides, comparing CFRP and Glass Fibre Reinforced Polymer (GFRP), CFRP showed it able to reduce stress compared to GFRP when tested on the same defected elbow. Lastly, the flow simulation in CFD showed there were no leakages especially on defected area and no sudden changes on pressure, velocity, and temperature.

Composite materials are widely used as repair materials in the oil and gas sector, particularly for vessels, piping, and pipelines. Inspection and monitoring of these composite repairs is a critical aspect of ensuring their integrity and long-term performance. The reason being that failure of composite repairs may lead to loss of production and incur additional costs for re-repair or equipment replacement. Conventionally, a visual inspection is generally performed to observe any irregularities on the external surface of the composite repairs. This will usually be followed by a series of Non-destructive Tests (NDT) to identify the extent of the damage. However, these NDT methods, merely allowing off-line testing in a local manner with complicated and heavy equipment, require extensive and time-consuming labour. Structural Health Monitoring (SHM) based on Fibre Bragg Grating (FBG) that utilizes strain-based signals is one of the best options for monitoring the damage mechanism in composite due to its unique advantages of light weight, high stability and reliability, a long-life cycle, and the ability to capture the online reading. In this paper, the application of the FBG monitoring approach was used to examine the strain characteristics of composite materials based on mechanical tests (tensile and flexural). Three types of samples were prepared to simulate the type of damage mechanism: healthy, delamination, and disbondment. Based on the results, it was shown that the FBG sensor has potential for detecting and distinguishing the types of failure mechanisms in composites, including cracks, delamination, and disbondment. Hence, it was suggested that the FBG sensor technology could be used for site deployment in industry.

Dents are among the most common deformation defects in buried transmission pipelines, significantly influencing structural integrity and internal flow behaviour. This study examines the occurrence of turbulence in dented pipe sections using time–frequency analysis of acoustic emission (AE) responses. The approach aims to overcome the challenge of obtaining meaningful information from AE signals during conventional dent inspections. By correlating AE spectral characteristics with flow-induced turbulence, the study provides insights into how mechanical deformation influences AE signal behaviour, contributing to an improved assessment of pipeline integrity. In this study, AE signals were captured during flow loop tests on healthy, 5%, 15%, and 30% dented pipe sections to evaluate the influence of dent severity on turbulence behaviour. Time–frequency domain analysis using the Morlet wavelet transform on the starting, middle, and end segments of AE signals revealed a progressive increase in signal energy with increasing dent depth, reaching a maximum of 2.54 × 10⁻⁰⁸ μE²/Hz − 2.54 × 10⁻⁰⁸ μE²/Hz for the end segment of AE signals under the 30% dented pipe condition. Complementary computational fluid dynamics (CFD) simulations were performed to compute velocity streamlines and corresponding Reynolds numbers for validating the turbulence detection results. A strong correlation between the CWT coefficient energy and Reynolds number, with R² values of 0.9633, 0.9007, and 0.9052 for the starting, middle, and end signal segments, respectively, was observed. These findings demonstrate that AE time–frequency analysis offers a reliable diagnostic approach for identifying and characterising dent-induced turbulence in pipeline systems.