Advances in structural analysis and process monitoring of thermoplastic composite pipes.

Thermoplastic composite pipes (TCP) in comparison to other pipes have proven beneficial features due to its flexibility which includes being fit for purpose, lightweight and no corrosion. However, during the manufacturing of TCP which involves the consolidation process, certain defects may be induced in it because of certain parameters, and this can affect the performance of the pipe in the long run as the induced defects might lead to in-service defects. Current techniques used in the industry are facing challenges with on-the-spot detection in a continuous manufacturing system. In TCP manufacturing process, the pipe is regularly monitored. When a defect is noticed, the whole process stops, and the appropriate action is taken. However, shutting down the process is costly; hence it is vital to decrease the downtime during manufacturing to the barest minimum. The solutions include optimizing the process for reduction in the manufacturing defects amount and thoroughly understanding the effect of parameters which causes certain defect types in the pipe. This review covers the current state-of-the-art and challenges associated with characterizing the identified manufacturing induced defects in TCP. It discusses and describes all effective consolidation monitoring strategy for early detection of these defects during manufacturing through the application of suitable sensing technology that is compatible with the TCP. It can be deduced that there is a correlation between manufacturing process to the performance of the final part and selection of characterization technique as well as optimizing process parameters

Manufacturing defects in thermoplastic composite pipes and their effect on the in-situ performance of thermoplastic composite pipes in oil and gas applications.

Thermoplastic composite pipes (TCP), which are a form of fibre reinforced thermoplastic pipes, have proven benefits such as being lightweight and non-corrosive. However, during manufacturing, certain defects are induced because of certain parameters, which eventually affect TCP performance in-service. Current manufacturing techniques are challenged with on-the-spot detection as the pipe is regularly monitored. When a defect is noticed, the process stops and action is taken. However, stopping the process is costly; hence it is vital to decrease downtime during manufacturing. Potential solutions are through process optimisation for defect reduction and an in-depth understanding of the effect of parameters that cause defect formation in the pipe. This article provides an overview of manufacturing influence on end performance. This is intimately linked to the material features, properties and performance in-service. The material features are the determinants for the manufacturing technique to be used. For TCP, it is a melt fusion bonding process involving heating and consolidation (other factors are consolidation speed and pull force). Thermal behaviour is essential at this phase as it determines the curing rate, hence it is deduced that laser heating is the better heat source in efficiency terms. Defects such as fibre misalignments, voids and delamination are induced here. The sources of these defects have been discussed herein as well as the secondary defects caused by them, with consideration of residual stress impact. The presence of manufacturing defects has been identified to influence performance in terms of strength and stiffness, interlaminar shear strength, toughness and creep. The next phase is to explore the state of the art in defect characterization during manufacturing for TCP. The in-situ characterization aims to derive high-quality TCP with reduced defects and need for repairs, and increased production rate in safe and eco-friendly conditions, while maintaining the current manufacturing process