Nondestructive inspection of thick, multi-layered thermoplastic composite pipes
Topic(s) : Material and Structural Behavior - Simulation & Testing
Co-authors :
Guillaume PORS (FRANCE), Mohd Fadzil MOHD TAHIR , Andreas ECHTERMEYER (NORWAY), Oriane FEDRIGO (FRANCE)Abstract :
This presentation describes how ultrasound and X-ray tomography can be used to detect damage in thick-walled thermoplastic composite pipes (TCP) and reinforced thermoplastic pipes (RTP). The work is part of a collaborative initiative to establish a standardized framework for ensuring the structural integrity of composite pipes which are used in the oil and gas industry and have future potential in energy transition, with a specific focus on hydrogen transport. The load-bearing composite laminate layers in TCP are composed of fiber reinforcement embedded in thermoplastic matrix materials, whereas RTP is constructed with dry fiber reinforcement layers.
Non-destructive inspection of those materials, after manufacturing or in-field is a challenge. Existing nondestructive techniques, which were primarily developed for traditional metal pipes and, with a slightly reduced capability, relatively thin composites, struggle to effectively address anomalies that can be found in thick multi-layered materials. This collaborative project focuses on overcoming the limitations of current technology in inspecting such materials. Test specimens were controlled with phased array ultrasonic, employing the classical time-corrected gain method. This approach leveraged the limitations posed by high attenuation and scattering effects in thick TCP/RTP materials and the differentiation between signals obtained from reinforcement layers and those indicative of real defects.
The efficacy of the proposed technique was initially demonstrated through testing on artificial flat bottom holes oriented favorably to the ultrasound wave propagation. The proposed technique demonstrated reliable detectable signals with good signal-to-noise ratios. Subsequently, it successfully identified internal, invisible defects within the laminate layers introduced during manufacturing and actual delamination or impact damage. The defect shapes reported by the proposed method were further validated using X-ray computed tomography. This imaging-based technique offers three-dimensional visualizations of the internal structures of the tested materials and is complementary to the ultrasonic-wave-based inspection technique.
Despite the randomly oriented damages of the actual delamination and impact, which are unfavorable to the wave propagation, results obtained from the ultrasonic-wave-based technique were found to be consistent with those acquired from the X-ray imaging-based technique. Hence, the ultrasonic technique holds promise for immediate practical field applications utilizing the existing technology. In contrast, computed tomography faces challenges that currently limit its use to laboratory or controlled environments due to technical constraints such as size, portability, power requirements, safety concerns, operational speed, and cost.
Non-destructive inspection of those materials, after manufacturing or in-field is a challenge. Existing nondestructive techniques, which were primarily developed for traditional metal pipes and, with a slightly reduced capability, relatively thin composites, struggle to effectively address anomalies that can be found in thick multi-layered materials. This collaborative project focuses on overcoming the limitations of current technology in inspecting such materials. Test specimens were controlled with phased array ultrasonic, employing the classical time-corrected gain method. This approach leveraged the limitations posed by high attenuation and scattering effects in thick TCP/RTP materials and the differentiation between signals obtained from reinforcement layers and those indicative of real defects.
The efficacy of the proposed technique was initially demonstrated through testing on artificial flat bottom holes oriented favorably to the ultrasound wave propagation. The proposed technique demonstrated reliable detectable signals with good signal-to-noise ratios. Subsequently, it successfully identified internal, invisible defects within the laminate layers introduced during manufacturing and actual delamination or impact damage. The defect shapes reported by the proposed method were further validated using X-ray computed tomography. This imaging-based technique offers three-dimensional visualizations of the internal structures of the tested materials and is complementary to the ultrasonic-wave-based inspection technique.
Despite the randomly oriented damages of the actual delamination and impact, which are unfavorable to the wave propagation, results obtained from the ultrasonic-wave-based technique were found to be consistent with those acquired from the X-ray imaging-based technique. Hence, the ultrasonic technique holds promise for immediate practical field applications utilizing the existing technology. In contrast, computed tomography faces challenges that currently limit its use to laboratory or controlled environments due to technical constraints such as size, portability, power requirements, safety concerns, operational speed, and cost.