Electromagnetic-mechanical repair patch of radar-absorbing structure with electroless nickel–plated glass fabric damaged by lightning strike

2020 ◽  
pp. 002199832096155
Author(s):  
Gi-Won Jeong ◽  
Yeong-Hoon Noh ◽  
Won-Ho Choi ◽  
Joon-Hyung Shin ◽  
Jin-Hwe Kweon ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Electroless Nickel ◽  
Glass Fabric ◽  
Lightning Strike ◽  
Reinforced Plastics ◽  
Repair Patch ◽  
Repair Efficiency ◽  
Mechanical Repair ◽  
Echo Radar ◽  
Radar Absorbing Structure

This paper presents an electromagnetic-mechanical repair patch (EMRP) to restore the mechanical and electromagnetic (EM) wave absorption performance of a radar-absorbing structure (RAS) damaged by lightning strike. Several researchers have primarily focused on ensuring high repair efficiency, particularly in terms of the primary load-bearing properties of repaired fiber-reinforced plastics. However, no study has proposed a practical repair approach that considers the multi-functionality of the radar-absorbing structure. The EMRP method can be used to repair lightning strike damage in a radar-absorbing structure with electroless nickel-plated glass fabric, considering the need to maintain structural integrity and electrical continuity to achieve a high repair efficiency. Damage due to an artificial lightning strike was assessed in terms of area and depth of the damage using image processing, ultrasonic C-scan, and micro X-ray inspection. The EM characteristics of one-dimensional return loss scanning and the echo radar-cross-section level were measured to verify the stealth performance of the repaired radar absorber in the X-band. In addition, the tensile test results demonstrated that the repaired radar absorber had a high recovery rate of 93% compared to the pristine radar absorber. The experimental results obtained in this study validate the use of the proposed EMRP method in repairing radar-absorbing structures.

Radar-absorbing foam-based sandwich composite with electroless nickel-plated glass fabric

2020 ◽  
Vol 243 ◽  
pp. 112252 ◽  
Author(s):  
Won-Ho Choi ◽  
Byeong-Su Kwak ◽  
Jin-Hwe Kweon ◽  
Young-Woo Nam
Keyword(s):  
Electroless Nickel ◽  
Glass Fabric ◽  
Sandwich Composite

scholarly journals Electrically conductive carbon fiber layers as lightning strike protection for non-conductive epoxy-based CFRP substrate

2020 ◽  
Vol 54 (29) ◽  
pp. 4547-4555 ◽  
Author(s):  
Siwat Manomaisantiphap ◽  
Vipin Kumar ◽  
Takao Okada ◽  
Tomohiro Yokozeki
Keyword(s):  
Carbon Fiber ◽  
High Speed ◽  
Lightning Strike ◽  
Fiber Reinforced ◽  
Electrically Conductive ◽  
Lightning Strikes ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
Hybrid Laminate

A large amount of electrically conductive fillers is needed to enhance a Carbon Fiber Reinforced Plastics (CFRP) electrical conductivity enough to withstand lightning strikes of peak currents. However, such large alien constituents hamper the inherent good mechanical properties of CFRP structures. In this work, a solution has been proposed to retain both desired properties in a CFRP laminate. Layer-wise hybrid laminate has been demonstrated as a solution for lightning strike protection of Carbon Fiber Reinforced Plastics (CFRP). Top few layers of a hybrid laminate are prepared using electrically conductive polymer-based resin (CF/C-POLY) to provide effective dissipation of lightning current while epoxy-based CFRP substrate (CF/Epoxy) provides the main structural strength. An insulating adhesive layer is used to bond CF/C-POLY and CF/Epoxy to prepare the laminate. The hybrid laminates were tested for their effectiveness against lightning strikes. Laminates were struck by modified lightning waveform of component A with peak current of -14 kA and -40 kA. The performance of the laminates against lightning strike were evaluated using high speed camera, high-speed and thermal camera. It is found that CF/C-POLY layer successfully defended the main structural component i.e. CF/Epoxy from lightning direct damage.

Thin and lightweight radar-absorbing structure containing glass fabric coated with silver by sputtering

2017 ◽  
Vol 160 ◽  
pp. 1171-1177 ◽  
Author(s):  
Young-Woo Nam ◽  
Jae-Hun Choi ◽  
Won-Jun Lee ◽  
Chun-Gon Kim
Keyword(s):  
Glass Fabric ◽  
Radar Absorbing Structure

A Review of Damage Tolerant Design, Certification and Repair in Metals Compared to Composite Materials

2014 ◽  
Vol 891-892 ◽  
pp. 1597-1602 ◽  
Author(s):  
Nabil Chowdhury ◽  
Wing Kong Chiu ◽  
John Wang
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Failure Modes ◽  
Structural Integrity ◽  
Fiber Reinforced Polymers ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Repair Efficiency ◽  
Mechanically Fastened ◽  
Damage Tolerant

A review of some of the various fatigue models introduced over the years for both metallic materials, in particular aluminium alloys followed by fatigue and durability concerns associated with composite materials. The move towards light weight and high stiffness structures that have good fatigue durability and corrosion resistance has led to the rapid move from metal structures to composite structures. With this brings the added concern of certifying new components as the damage mechanisms and failure modes in metals differ significantly than composite materials such as carbon fiber reinforced polymers (CFRP). The certification philosophy for composites must meet the same structural integrity, safety and durability requirements as that of metals. Hence this is where the challenge now lies. Substantial work has been conducted in the reparability of composite structures through bonding using various adherend thicknesses and joint types and has been shown to have higher durability than mechanically fastened repairs for thin adherends however these are currently unacceptable repair methods as they cannot be certified. Repairs are designed on the basis that the repair efficiency can be predicted and should be designed conservatively with respect to the various failure modes and include the surrounding structure.

Elastic characteristics of multilayer glass fabric-reinforced plastics

2004 ◽  
Vol 36 (6) ◽  
pp. 565-569 ◽  
Author(s):  
N. K. Kucher ◽  
A. Z. Dveirin ◽  
M. P. Zemtsov ◽  
O. K. Ankyanets
Keyword(s):  
Glass Fabric ◽  
Reinforced Plastics ◽  
Elastic Characteristics

Nondestructive Evaluation of Rayleigh Pitch-Catch Contact Ultrasound Waves on Impacted-Damaged Composites

2007 ◽  
Vol 566 ◽  
pp. 267-272 ◽  
Author(s):  
Je Woong Park ◽  
In Young Yang ◽  
Kwang Hee Im ◽  
David K. Hsu ◽  
Sung Jin Song ◽  
...  
Keyword(s):  
Nondestructive Evaluation ◽  
Material Properties ◽  
Composite Structures ◽  
Structural Integrity ◽  
Normal Incidence ◽  
Ultrasound Waves ◽  
Reinforced Plastics ◽  
Cfrp Composite ◽  
Sampling Volume ◽  
Automated Data Acquisition

In particular, CFRP (carbon fiber reinforced plastics) composite materials have found wide applicability because of their inherent design flexibility and improved material properties. CFRP composites were manufactured from uni-direction prepreg sheet in this paper. However, impacted composite structures have 50-75% less strength than undamaged structures. It is desirable to perform nondestructive evaluation to assess material properties and part defect in order to ensure product quality and structural integrity of CFRP. In this work, a CFRP composite material was nondestructively characterized and a pitch-catch technique was developed to measure impacteddamaged area using an automated-data acquisition system. Also one-sided mode was performed to scan defect both manual contact measurement and an immersion tank. It is found a pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composite, including fiber orientation, low level porosity, ply waviness, and cracks. The paper describes the depth of the sampling volume with the head-to-head miniature Rayleigh probes and also ultrasonic C-scan images are acquired experimentally using one-sided measurement and a conventional scanner.

Evaluation of the Mechanical Properties of Repaired Composite Panels Using Resin Re-Infusion Process

2020 ◽  
Author(s):  
Mahmoud E. Abd El-Latief ◽  
Mostafa Shazly ◽  
Yehia Bahei-El-Din
Keyword(s):  
Mechanical Properties ◽  
Structural Integrity ◽  
Tensile Tests ◽  
Bending Tests ◽  
Reinforced Plastics ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Plastics ◽  
Air Pockets ◽  
Failure Location ◽  
Infusion Technique

Abstract Glass Fiber Reinforced Plastics (GFRP) have been used in many fields such as aerospace, automotive and wind energy sectors. During their manufacturing processes, some defects such as dry spots and air pockets may develop in impregnated fabric, especially, when metallic inserts are used. To evaluate the interface between parent and repaired parts, an experimental study is performed to investigate its effect on the mechanical properties and structural integrity. To compare the response of the re-infused and intact samples, several tensile and bending tests were performed for uniaxial glass reinforcing fabric with tailored orientation for the interface between the intact and repaired regions. The results showed that for the tensile tests, repaired specimens with interfaces having 90° and 45° orientations w.r.t. loading direction were able to recover 80% and 73%, respectively, from the tensile strength of samples produced by vacuum infusion technique. However, for bending tests, the flexural strength was recovered by almost 90% and 72% for both interfaces, respectively. Based on visual inspection, each type of tested specimen has a typical dominant failure mode. For re-infused samples, the properties of the parent and repaired laminates determine the failure location.

Sign in / Sign up

Export Citation Format

Share Document