Study on probability of detection (POD) determination using lock-in thermography for nondestructive inspection (NDI) of CFRP composite materials

2015 ◽  
Vol 71 ◽  
pp. 448-456 ◽  
Author(s):  
Liu Junyan ◽  
Liu Yang ◽  
Wang Fei ◽  
Wang Yang
Keyword(s):  
Composite Materials ◽  
Nondestructive Inspection ◽  
Probability Of Detection ◽  
Cfrp Composite ◽  
Lock In

scholarly journals High-Speed Time- and Frequency-Domain Terahertz Tomography of Glass-Fiber-Reinforced Polymer Laminates with Internal Defects

2021 ◽  
Vol 11 (11) ◽  
pp. 4933
Author(s):  
Ji-Sang Yahng ◽  
Dae-Su Yee
Keyword(s):  
Composite Materials ◽  
Glass Fiber ◽  
High Speed ◽  
Nondestructive Inspection ◽  
Fiber Reinforced Polymer ◽  
Glass Fiber Reinforced Polymer ◽  
Tomographic Images ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Thz Tomography

Composite materials are increasingly being utilized in many products, such as aircrafts, wind blades, etc. Accordingly, the need for nondestructive inspection of composite materials is increasing and technologies that allow nondestructive inspection are being studied. Existing ultrasound methods are limited in their ability to detect defects due to high attenuation in composite materials, and radiographic examination methods could pose a danger to human health. Terahertz (THz) wave technology is an emerging approach that is useful for imaging of concealed objects or internal structures due to high transmittance in non-conductive materials, straightness, and safety to human health. Using high-speed THz tomography systems that we developed, we have obtained THz tomographic images of glass-fiber-reinforced polymer (GFRP) laminates with artificial internal defects such as delamination and inclusion. The defects have various thicknesses and sizes, and lie at different depths. We present THz tomographic images of GFRP samples to demonstrate the extent to which the defects can be detected with the THz tomography systems.

scholarly journals On the Thickness Quantification of Composite Materials by Using Lock-In Thermography

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1185
Author(s):  
Davide Palumbo
Keyword(s):  
Composite Materials ◽  
Measurement Accuracy ◽  
Plastic Material ◽  
Thickness Measurement ◽  
Glass Fiber Reinforced Plastic ◽  
Glass Fiber Reinforced ◽  
Reinforced Plastic ◽  
Test Parameters ◽  
Lock In ◽  
Non Destructive

Many structural components made of composite materials need an accurate thickness control during fabrication and/or maintenance. In this regard, various non-destructive techniques can be used for the online measuring of thickness of large components such as wings and fuselage in the aerospace industry. In this work, the capabilities of lock-in thermography technique in thickness measurement of glass fiber reinforced plastic material were investigated and a correct procedure has been proposed to ensure the best measurement accuracy. An analytical approach and several tests were carried out on a sample specimen with the aim to study the main test parameters. Finally, the limits of technique have been discussed.

scholarly journals Microwave Curing Characteristics of CFRP Composite Depending on Thickness Variation Using FBG Temperature Sensors

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1720 ◽  
Author(s):  
Heonyoung Kim ◽  
Donghoon Kang ◽  
Moosun Kim ◽  
Min Hye Jung
Keyword(s):  
Composite Materials ◽  
Thickness Variation ◽  
Specimen Thickness ◽  
Curing Time ◽  
Microwave Curing ◽  
Cure Monitoring ◽  
Curing Characteristics ◽  
Cfrp Composite ◽  
Curing Cycle

Microwave curing technology, which has seen increased commercialization recently due to its ability to cut the curing time and ensure high quality, requires an understanding of the curing characteristics of composite materials of varying thickness. Therefore, this study aimed to perform cure monitoring to evaluate the effects of variations in thickness on the quality of microwave curing. For this study, a fiber Bragg grating sensor was used to measure temperature changes in specimens during the curing cycle for cure monitoring which is generally used for optimization of the curing cycle; then, the time taken for temperature increase and overshoot of the specimen, and the times at which the specimen thickness varied, were quantitatively evaluated. Testing confirmed that microwave curing reduced the curing time in the sections in which the temperature rose; also, the specimen thickness caused overshoot of up to approximately 40 °C at the side, which can affect the curing quality of the composite materials. Furthermore, voids were observed on the side of all specimens. The results indicated that, in order to improve the quality of microwave curing of composite materials, the curing cycle should be optimized by considering the characteristics of the microwave curing equipment.

Ultrasonic Nondestructive Approach on Fiber Orientation Inspection in CFRP Composite Laminates

2007 ◽  
Vol 566 ◽  
pp. 261-266
Author(s):  
In Young Yang ◽  
Yong Jun Yang ◽  
Kil Sung Lee ◽  
David K. Hsu ◽  
Kwang Hee Im
Keyword(s):  
Composite Materials ◽  
Shear Wave ◽  
Fiber Orientation ◽  
Composite Laminates ◽  
Isosceles Triangle ◽  
Orientation Error ◽  
Engineering Structures ◽  
Orthotropic Composite ◽  
Wide Range ◽  
Cfrp Composite

Owing to the advantages associated with their very large strength-to-weight and stiffnessto- weight ratios, composite materials are attractive for a wide range of applications. Increasingly, high performance engineering structures are being built with critical structural components made from composite materials. In particular, the importance of carbon-fiber reinforced plastics (CFRP) has been generally recognized in both space and civil aircraft industries, and CFRP composite laminates are widely used. It is very important to detect fiber orientation error in orthotropic composite laminates because the layup of a CFRP composite laminates affects the properties of the laminate, including stiffness, strength and thermal behavior. In this study, a new approach was investigated on detection of fiber orientation with using two longitudinal and a shear wave ultrasonic transducers for the orthotropic composite laminates. During testing, the most significant problem is that the couplant conditions do not remain the same because of changing the viscosity of the couplant. Therefore, making a design for generating shear wave with longitudinal transducers would greatly aid in alleviating the couplant problem. A pyramid with an isosceles triangle was made of aluminum in order to generate shear waves using two longitudinal transducers based on ultrasonic-polarized mechanism. It is found that the shear wave was very sensitive to fiber of CFRP composite. Finally, a CFRP composite material was nondestructively characterized in order to measure fiber orientation error area using automated data acquisition C-scan system.

Research on the Properties of the Concrete Filled Steel Tube Columns with CFRP Composite Materials

2010 ◽  
Vol 163-167 ◽  
pp. 3555-3559
Author(s):  
Wei Gu ◽  
Hong Nan Li
Keyword(s):  
Composite Materials ◽  
Research Program ◽  
Steel Tube ◽  
Experimental Results ◽  
Composite Tubes ◽  
Concrete Filled Steel Tube ◽  
Damage Area ◽  
Cfrp Composite ◽  
Axially Loaded ◽  
Strengthening Method

This paper presents a phase of the research program to determine the feasibility of a proposed CFRP retrofit method to strengthen the corroded concrete filled steel tube columns. This method is wrapping the corroded concrete filled steel tube column with CFRP material. Eight concrete filled steel tube columns were tested in the laboratory with four of them strengthened using the proposed technique. All specimens were notched in the center zone to simulate the loss of section due to corrosion the four of them were wrapped with CFRP composite tubes in the damage area. All specimens were axially loaded to failure while strain and displacement were measured to demonstrate the validity of this repair concept. This paper presents the experimental results and discusses the findings with preliminary conclusions on the feasibility of the proposed strengthening method.

scholarly journals Research on anchorages of the structural strengthening system with prestressed CFRP strips

2014 ◽  
Vol 13 (3) ◽  
pp. 143-150
Author(s):  
Paulina Paśko ◽  
Bartosz Piątek ◽  
Tomasz Siwowski
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Materials ◽  
Ultimate Tensile Strength ◽  
Carrying Capacity ◽  
Steel Joint ◽  
Capacity Level ◽  
Cfrp Composite ◽  
Anchoring System ◽  
System Effectiveness

The CFRP composite materials due to their excellent mechanical properties are more often used in civil engineering. In recent more than ten years has been observed e.g. much wider application of CFRP strips in structural strengthening. The research on this subject clearly showed the advantages of prestressed strips application in contrast to passive one. The CFRP utilization is much more effective in terms of strength and economy. However, the system effectiveness depends on reliability of anchoring used for prestressed strips. The main goal of the research presented in the paper was to develop a new, innovative, effective and reliable anchoring system for CFRP strips. The achievement of quite high carrying capacity of new anchorages was able thanks to combining friction, bonding and rivet clamping in one CFRP-steel joint. The research results revealed the effectiveness of new anchoring system with carrying capacity level of about 70% of the CFRP ultimate tensile strength.

Sign in / Sign up

Export Citation Format

Share Document