“…Such damage has also been reported in many experimental studies for CFRP composites subjected to simulated lightning strike tests. 9,11,14 Figure 9.SEM images for (a) Panel 3 and (b) Panel 4 at varying magnification levels.…”
Section: Resultsmentioning
confidence: 99%
“…Such damage has also been reported in many experimental studies for CFRP composites subjected to simulated lightning strike tests. 9,11,14 Figure 10 shows the SEM images for Panel 3 at the central regions where massive matrix charring and material loss (0.4 mm in radius, 0.8 mm through the thickness) due to fiber vaporization can be observed, and the char residue was deposited at the ends of the broken fibers. The results imply that the damage of the GFRP composite material when subjected to the HVAC puncture is more dictated by the thermal effect, whereas the damage when subjected to the LI voltage waveform A strike is more dictated by the impact effect, potentially due to the shock wave and electromagnetic force produced by the lightning strike.…”
Section: High Voltage Puncture Damage Characteristicsmentioning
confidence: 99%
“…The fundamental effects of high voltage discharge on fiber composites and metallic materials have drawn growing attention and been investigated by a number of experimental and theoretical studies. 3–26 For instance, numerous studies 3–6,8–15,26–28 have focused on the lightning strike damage of aircraft carbon fiber-reinforced polymer matrix (CFRP) composites. It has been recognized that the Joule heating is the primary cause of the lightning strike damage for CFRP composite panels, and the electrical conductivity played a significant role in the Joule heating generation.…”
Understanding the damage mechanisms of fiber-reinforced polymer matrix composite materials under high voltage conditions is of great significance for lightning strike protection and high voltage insulation applications of composite structures. In this paper, we investigated effects of the lightning impulse (LI) voltage and high voltage alternating current (HVAC) puncture on damage modes of the electrically nonconductive glass fiber-reinforced polymer (GFRP) matrix composite materials through experimental tests and numerical simulations. The LI and HVAC tests represent the lightning strike and high voltage insulation cable puncture conditions, respectively. Our experimental examinations showed that GFRP composite specimens subjected to the LI voltage test exhibited distinct damage modes compared with those in the HVAC puncture test. The GFRP composite material suffered more charring and fiber vaporization in the HVAC puncture test, whereas less matrix charring and fiber vaporization but severe fiber breakage and delamination in response to the LI voltage tests. The findings indicate that the thermal effect dominates the damage of GFRP composites inflicted by the HVAC puncture test, whereas the mechanical impact effect governs the GFRP composite damage in the LI voltage test. In addition, the electric arc plasma formation during the puncture of the GFRP composite material was modeled through solving Maxwell’s equations and the heat generation equations using finite element analysis. Simulation results provided insights on the effects of duration and intensity of the high voltage electric discharge on the composite damage.
“…Such damage has also been reported in many experimental studies for CFRP composites subjected to simulated lightning strike tests. 9,11,14 Figure 9.SEM images for (a) Panel 3 and (b) Panel 4 at varying magnification levels.…”
Section: Resultsmentioning
confidence: 99%
“…Such damage has also been reported in many experimental studies for CFRP composites subjected to simulated lightning strike tests. 9,11,14 Figure 10 shows the SEM images for Panel 3 at the central regions where massive matrix charring and material loss (0.4 mm in radius, 0.8 mm through the thickness) due to fiber vaporization can be observed, and the char residue was deposited at the ends of the broken fibers. The results imply that the damage of the GFRP composite material when subjected to the HVAC puncture is more dictated by the thermal effect, whereas the damage when subjected to the LI voltage waveform A strike is more dictated by the impact effect, potentially due to the shock wave and electromagnetic force produced by the lightning strike.…”
Section: High Voltage Puncture Damage Characteristicsmentioning
confidence: 99%
“…The fundamental effects of high voltage discharge on fiber composites and metallic materials have drawn growing attention and been investigated by a number of experimental and theoretical studies. 3–26 For instance, numerous studies 3–6,8–15,26–28 have focused on the lightning strike damage of aircraft carbon fiber-reinforced polymer matrix (CFRP) composites. It has been recognized that the Joule heating is the primary cause of the lightning strike damage for CFRP composite panels, and the electrical conductivity played a significant role in the Joule heating generation.…”
Understanding the damage mechanisms of fiber-reinforced polymer matrix composite materials under high voltage conditions is of great significance for lightning strike protection and high voltage insulation applications of composite structures. In this paper, we investigated effects of the lightning impulse (LI) voltage and high voltage alternating current (HVAC) puncture on damage modes of the electrically nonconductive glass fiber-reinforced polymer (GFRP) matrix composite materials through experimental tests and numerical simulations. The LI and HVAC tests represent the lightning strike and high voltage insulation cable puncture conditions, respectively. Our experimental examinations showed that GFRP composite specimens subjected to the LI voltage test exhibited distinct damage modes compared with those in the HVAC puncture test. The GFRP composite material suffered more charring and fiber vaporization in the HVAC puncture test, whereas less matrix charring and fiber vaporization but severe fiber breakage and delamination in response to the LI voltage tests. The findings indicate that the thermal effect dominates the damage of GFRP composites inflicted by the HVAC puncture test, whereas the mechanical impact effect governs the GFRP composite damage in the LI voltage test. In addition, the electric arc plasma formation during the puncture of the GFRP composite material was modeled through solving Maxwell’s equations and the heat generation equations using finite element analysis. Simulation results provided insights on the effects of duration and intensity of the high voltage electric discharge on the composite damage.
“…Owing to its superior specific strength and stiffness, carbon fibre reinforced polymer (CFRP) composites are increasingly being used in diverse sectors, such as marine, automotive, sports and, in particular, aerospace, where they comprise around half the weight of the primary structure of the latest generation wide-body passenger aircraft such as the Boeing 787 and A350 XWB (1) . This revolution in materials and fabrication, together with ever increasing pressure to reduce fuel consumption has provided the impetus for the development of multifunctional structures incorporating such functionality as structural health monitoring (SHM) (2)(3)(4)(5) , lightning strike protection (LSP) (6)(7)(8)(9)(10) and improved ice protection systems (11)(12)(13)(14)(15)(16)(17)(18) whilst also delivering enhanced structural performance such as higher interlaminar fracture toughness (ILFT) (19)(20)(21)(22)(23) . Directly drawable carbon nanotube web (CNT web) is a uniquely adaptable and useful material composed of highly aligned, small multiwalled CNTs.…”
We previously described an efficient, lightweight and flexible electro-thermal system, based on directly drawn carbon nanotube web (CNT web), as part of an icing protection system for carbon fibre reinforced polymer (CFRP) composite aircraft structures. The location of the heating elements on critical lifting surface leading edges or nacelle intake lips makes them particularly susceptible to impact damage, which may leave no visible mark. This makes it desirable to have both a mechanism for identifying the location of damage to the CNT structure (and by inference, potential damage to the underlying CFRP) and a process for restoring the CNT heater to full operation. With the CNT web acting as a sensor, impact damage is identified by an increase in electrical resistance and, particularly, by infrared imaging, which reveals a cold spot or zone depending upon the CNT web layup. Whereas a unidirectional CNT web layup exhibits a large increase in resistance and loss of a full width band of operation, a cross ply quasi-isotropic CNT web arrangement suffers only a small increase in resistance and a loss of function that is highly localised to the damaged area. A novel methodology, based on dispersed CNT in resin, is described for repairing and reconnecting the CNT structure and restoring functionality. A CNT web-based electro-thermal element was applied to the leading edge of a representative carbon-fibre composite wing section to demonstrate the flexibility of this system.
“…However, structural damage on the composite laminates still existed. Aiming at the problem of poor conductivity of composite materials, the copper and aluminum meshes (expanded metal foils) are the mostly adopted LSP solutions for CFRP-based aircraft because of their high conductivity [24][25][26]. Moreover, the metal modified materials, such as Ni-coated carbon nano-tubes (CNTs) [27,28], silver modified buckypaper [29], and metallized carbon fiber veil [30,31] were also developed for LSP.…”
：According to simulation lightning experiments and eddy current analysis results, a three-dimensional finite element model of composite laminated plates with shield is established. By applying electric-thermal boundary and the coupling relationship between them, the lightning strike damage results under the protection of shield are realistically simulated with the commercial finite element analysis software, ABAQUS. Considering the coupling effect of heat, electricity, and force during lightning strike, the load distribution field of copper mesh and carbon fiber panel with lightning current inducted is analyzed. Comparing the thermal stress distribution of the specimen surface under various current loads, it is shown that the stress of carbon fiber panel is significantly lower than the one of the copper screen when the specimen structure suffers heavy current, since the copper network plays a role of endergonic protection. Simulation data are consistent with the test results, thus the method can be used for other similar research.
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