Nondestructive testing and evaluation techniques of defects in fiber-reinforced polymer composites: A review

Abstract

Fiber-reinforced polymer composites have excellent mechanical properties and outstanding development potential and are cost-effective. They have increasingly been used in numerous advanced and engineering applications as materials for wind turbine blades, helicopter rotors, high-pressure pipelines, and medical equipment. Understanding and assessing structural failure promptly in the whole lifecycle of a composite is essential to mitigating safety concerns and reducing maintenance costs. Various nondestructive testing and evaluation (NDT&E) technologies based on different evaluation principles have been established to inspect defects under different conditions. This paper reviews the established types of NDT&E techniques: acoustic emission, ultrasonic testing, eddy current testing, infrared thermography, terahertz testing, digital image correlation, shearography, and X-ray computed tomography, which is divided into three categories based on the operation frequency and data processing means of the output signal that is directly under analysis. We listed four types of defects/damage that are currently of great interest, namely, voids and porosity, fiber waviness and wrinkling, delamination and debonding, as well as impact damage. To identify a suitable method for different defects/damage, we performed characterization and evaluation by using these NDT&E techniques for typical defects/damage. Then, the cost, inspection speed, benefits and limitations, etc. were compared and discussed. Finally, a brief overview of the development of the technologies and their applications in the field of composite fabrication was discussed.

Acoustic-Signal-Based Damage Detection of Wind Turbine Blades—A Review

“…Recently, terahertz radiation (T-ray) has received increasing attention for blade inspection. Currently, T-ray inspection techniques are most often used for composite wind turbine blade impact damage and wind turbine blade trailing edge cracking damage detection [38][39][40][41]. However, composites consisting of carbon fibers can limit the propagation of T-rays.…”

Damage localization in large-area FRP composites using a parallel array of self-sensing carbon fiber tows

“…8,9 NDT&E allows the investigator to inspect the materials without permanent alteration through the use of external equipment, including techniques such as acoustic emission, ultrasonic testing, eddy current testing, infrared thermography, terahertz testing, digital image correlation, shearography, and X-ray computed tomography. [10][11][12] However, one significant limitation of NDT&E methods is the requirement for the composite to be taken out of service and tested. Consequently, periodic NDT&E methods may fail to promptly characterize a damage event.…”

Nondestructive Evaluation of Tensile Stress-loaded GFRPs Using the Magnetic Recording Method

“…During the operational phase, the structure and structural material are monitored to detect signs of wear or the premature occurrence of dangerous states. Nondestructive testing methods are usually applied, starting from the simplest, such as organoleptic inspections, through various defectoscopy techniques (e.g., magnetic, X-ray, ultrasonic, microwave), deformation measurements, analyses of spontaneous emissions from the tested object (e.g., acoustic emission) or emissions induced by an agent with an intensity that does not pose a threat of damage to the object—mechanical, electrical, magnetic, or radiative [ 6 , 13 ].…”