Compression-after-Impact Testing of CFRP Laminates Subjected to Simulated Lightning Damage Monitored by Acoustic Emission

2012 ◽  
Vol 224 ◽  
pp. 73-76 ◽  
Author(s):  
Oh Yang Kwon ◽  
Jae Ha Shin
Keyword(s):  
Acoustic Emission ◽  
Carbon Fibers ◽  
Composite Structures ◽  
Impact Testing ◽  
Nano Particles ◽  
Lightning Strike ◽  
Lightning Strikes ◽  
Cfrp Laminates ◽  
Compression After Impact ◽  
Coated Carbon

CFRP laminates made of nano-particles-coated carbon fibers and damaged by a simulated lightning strike were tested under the compression-after-impact (CAI) mode, during which the damage progression was monitored by acoustic emission (AE). The effects of nano-particles coating on the degree of lightning-damage and the mechanical integrity of composite structures damaged by lightning strikes have been evaluated in terms of AE activities.

scholarly journals Design and Validation of a Modified Compression-After-Impact Testing Device for Thin-Walled Composite Plates

2020 ◽  
Vol 4 (3) ◽  
pp. 126 ◽  
Author(s):  
Markus Linke ◽  
Felix Flügge ◽  
Aurelio Jose Olivares-Ferrer
Keyword(s):  
Residual Strength ◽  
Composite Structures ◽  
Composite Plates ◽  
Impact Testing ◽  
Testing Device ◽  
Testing Procedures ◽  
New Device ◽  
Compression After Impact ◽  
Thin Walled ◽  
Impact Damages

Thin-walled fibre reinforced composites like carbon fibre reinforced plastics are very susceptible to strength reductions due to low-velocity impact damages. In aerospace engineering, the dominating failure mechanisms of impact damaged composite structures are usually investigated based on the compression after impact (CAI) test procedure. This enables the determination of the influence of impact damages on the static residual compressive strength. CAI testing procedures are typically applicable to composite plates with thicknesses larger than 3–4 mm. If thinner panels are used, they typically fail near one of the loaded edges of the CAI device, in particular the area of the free edge (which is needed for compressing the panel) and not within the free measuring area. As a consequence, the investigated samples cannot be used as valid tests for the evaluation of the residual strength in CAI testing. In order to enable an investigation of the residual strength of thin-walled plates in CAI testing, a CAI testing device is developed based on an available CAI fixture and a standardized one. For comparability reasons, this new device exhibits the same dimensions as standardized fixtures. It shows a significant improvement with respect to standardized devices concerning the measurement of mechanical behaviour during CAI testing.

scholarly journals Lightning Strike Protection of Aircraft Composite Structures: Analysis and Comparative Study

2016 ◽  
Vol 2016 (8) ◽  
pp. 49-54 ◽  
Author(s):  
Andrzej Katunin
Keyword(s):  
Comparative Study ◽  
Composite Structures ◽  
Conductive Polymers ◽  
Lightning Strike ◽  
Electrically Conductive ◽  
Lightning Strikes ◽  
Conductive Composites ◽  
University Of Technology ◽  
Electrical Conducting ◽  
Conductive Particles

AbstractLightning strikes are a serious problem during operation of aircraft due to the increasing applicability of polymeric composites in aircraft structures and the weak electrical conducting properties of such structures. In composite structures, lightning strikes may cause extended damage sites which require to be appropriately maintained and repaired leading to increased operational costs. In order to overcome this problem various lightning strike protection solutions have been developed. Some of them are based on the immersion of metallic elements and particles while others use novel solutions such as intrinsically conductive polymers or other types of highly conductive particles including carbon nanotubes and graphene. The concept of fully organic electrically conductive composites based on intrinsically conductive polymers is currently being developed at the Silesian University of Technology. The results obtained in numerous tests, including concerning electrical conductivity and the capability to carry on high-magnitude electrical charges as well as certain operating properties need to be compared with existing solutions in lightning strike protection of aircraft. The following study presents the properties of the material developed for lightning strike protection and a comparative study with other solutions.

Lightning Strike Protection and EMI Shielding of Fiber Reinforced Composite Using Gold and Silver Nanofilms

2018 ◽  
Author(s):  
Praveen K. Bollavaram ◽  
Muhammad M. Rahman ◽  
R. Asmatulu
Keyword(s):  
Carbon Fibers ◽  
Electromagnetic Interference ◽  
Weight Ratio ◽  
Lightning Strike ◽  
Surface Conductance ◽  
Composite Panels ◽  
Fiber Reinforced ◽  
Lightning Strikes ◽  
Composite Sandwich ◽  
Metallic Nanofilm

Carbon fiber reinforced composites are very much imperative to future-generation aircraft structures. However, lightning strike protection (LSP) and electromagnetic interference (EMI) are main concerns. Carbon fibers have very good mechanical properties with the best strength-to-weight ratio, but they are very poor conductors of electricity. These fibers must be reinvented to increase the surface conductance to provide high electrical conductivity to the aircraft structure. The present study deals with preparing composite sandwich structures of carbon fibers used for commercial nacelle applications subject to lightning strike effects with different metallic nanofilm of gold (Au) and silver (Ag) measuring approximately 100 nm. These metallic nanofibers were co-cured on the top layers of composite panels during vacuum curing process. In our laboratory, lightning strike results for a composite sandwich structure using nanofilms were obtained to observe lightning strike damage and structural tolerance necessary to observe the damage tolerance capability. Resistance of composite panels with metallic nanofilm under various strains was studied. It was found that resistance of the metallic nanofilm increased under strain. The voltage was found to be low; hence, an increase in current would help to reduce the damage on composite panels due to lightning strikes, and the same theory would be applicable to EMI. No EMI was absorbed or reflected in the nanofilm using the P-static test. When lightning strikes were applied to composite coupons, the resulting damage from the currents was reduced on those with metallic nanofilms.

Polyaniline doped graphene thin film to enhance the electrical conductivity in carbon fiber-reinforced composites for lightning strike mitigation

2021 ◽  
pp. 002199832110417
Author(s):  
Pralhad Lamichhane ◽  
Dilli R Dhakal ◽  
Siddhesh Chaudhari ◽  
Ishan N Jayalath ◽  
Toby Nelson ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Synergetic Effect ◽  
Lightning Strike ◽  
Fiber Reinforced ◽  
Lightning Strikes ◽  
Cfrp Laminates ◽  
Cfrp Composites ◽  
Doped Graphene ◽  
Carbon Fiber Reinforced

Multifunctional carbon fiber-reinforced polymer (CFRP) composites are promising structural materials for lightweight applications. However, the low conductivity in the through-thickness direction of the composites limits its applications in the fields that require the high stability of composite against lightning strikes. This work presents the study on the synergetic effect of conducting polymer, polyaniline (PANI), and graphene nanoplatelets (GNP) for increasing the electrical conductivity of CFRP composites. PANI doped GNP flexible film is fabricated with the aid of compatible polymer polyvinylpyrrolidone (PVP), and its effect on the electrical conductivity of CFRP composites has been studied. About 250% in through-thickness conductivity has improved with 11 wt% GNP as a function of the composite. The incorporation of conductive film not only increases the conductivity of the CFRP laminates but also enhances the resistance against lightning strikes. Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), three-point bending tests were used to analyze the morphology, thermal stability, and mechanical strengths of the composites. Finally, the observation of post-strike damage confirms the importance of through-thickness conductivity for mitigating the lightning strike damage.

Oxidation of carbon and metal coated carbon fibers

1970 ◽  
Vol 2 (4) ◽  
pp. 303-315 ◽  
Author(s):  
F.S. Galasso ◽  
J. Pinto
Keyword(s):  
Carbon Fibers ◽  
Coated Carbon

Cumulative acoustic emission energy for damage detection in composites reinforced by carbon fibers within low-cycle fatigue regime at various displacement amplitudes and rates

2021 ◽  
pp. 096739112098570
Author(s):  
Mohammad Azadi ◽  
Mohsen Alizadeh ◽  
Seyed Mohammad Jafari ◽  
Amin Farrokhabadi
Keyword(s):  
Acoustic Emission ◽  
Carbon Fibers ◽  
Polymer Matrix Composites ◽  
Low Cycle Fatigue ◽  
Energy Parameter ◽  
Fatigue Tests ◽  
Matrix Cracking ◽  
Matrix Composites ◽  
Cycle Fatigue ◽  
Cumulative Energy

In the present article, acoustic emission signals were utilized to predict the damage in polymer matrix composites, reinforced by carbon fibers, in the low-cycle fatigue regime. Displacement-controlled fatigue tests were performed on open-hole samples, under different conditions, at various displacement amplitudes of 5.5, 6.0, 6.5 and 7.0 mm and also under various displacement rates of 25, 50, 100 and 200 mm/min. After acquiring acoustic emission signals during cycles, two characteristic parameters were used, including the energy and the cumulative energy. Obtained results implied that the energy parameter of acoustic emission signals could be used only for the macroscopic damage, occurring at more than 65% of normalized fatigue cycles under different test conditions. However, the cumulative energy could properly predict both microscopic and macroscopic defects, at least two failure types, including matrix cracking at first cycles and the fiber breakage at last cycles. Besides, scanning electron microscopy images proved initially such claims under all loading conditions.

Sign in / Sign up

Export Citation Format

Share Document