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1

Ochrona odgromowa samolotów – problem, wynikający z postępów w lotnictwie

Katunin Andrzej

Przegląd Techniczny : Gazeta Inżynierska

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2022

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nr 8

17--20

PL

Wraz z szerokim wykorzystaniem kompozytów polimerowych jako materiału konstrukcyjnego w lotnictwie pojawił się nowy problem, nie występujący dotychczas w elementach metalowych samolotów. Problem dotyczy braku przewodności elektrycznej w nowoczesnych kompozytach polimerowych i w związku z tym konieczności zapewnienia takiej przewodności w celu ochrony odgromowej samolotów. Obecnie stosowane rozwiązania w tym zakresie zapewniają taką ochronę, jednak powodują wiele wyzwań, powodujących, że wciąż poszukiwane są nowe rozwiązania materiałowe, aby chronić samoloty przed piorunami skuteczniej i taniej.

EN

With the widespread use of polymer composites as a construction material in aviation, a new problem has arisen, which has not appear so far in metallic parts of aircraft. The problem relates to a lack of electrical conductivity in modern polymer composites, and therefore the need to provide such conductivity in order to ensure lightning strike protection. Currently used solutions in this area provide such protection, but generate a number of challenges, resulting in the fact that new material solutions are still being searched for in order to protect aircraft against lightning more effectively and cheaper.

2

Electrical properties study of fibre reinforced polymeric materials used in aircraft structures

Porras S., Mucha M.

Journal of KONES

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2018

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Vol. 25, No. 4

347--353

EN

Aircraft are exposed to lightning strikes. Lightning strike protection (LSP) devices involve additional weight of the aircraft. Therefore, multifunctional materials that allows the conductivity of electrical current and, simultaneously, holds the mechanical properties required to withstand the typical conditions for an aerospace material are widely researched. A typical resin used in aviation is an insulator, so main research is done to reduce its resistance. On the other hand, the type of reinforcement can have a large influence on the electrical conductivity in the plane of reinforcement. The aim of the article is to evaluate the effect of the type and the basis weight of reinforcement on the electrical conductivity. For this purpose, with the use of a hydraulic press, different four-layer composites based on epoxy resin were produced. Each differing is in combination of carbon, glass layers and their basis weight (from 48 kg/m2 to 245 kg/m2 ). The measuring proceedings were carried by an RMS multi meter and, more accurate, by an LCR meter with 4 selectable test frequencies. The measurements were made both along the strand fibres and at a 45-degree angle. The results made it possible to determine which reinforcement of aircraft composites should be selected at the aircraft design level to provide increased electrical conductivity along the reinforcement fibres and thus influence one of the factors affecting the protection of the aircraft against the effects of lightning

3

Flammability of electrically conductive composite dedicated for lightning strike protection

Katunin A., Bilewicz M.

Composites Theory and Practice

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2017

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R. 17, nr 3

131--135

EN

Lightning strike protection is one of the crucial structural demands for aircraft composites addressed to their integrity and durability after a strike. When the lightning strikes a classic composite structure, the generated heat from electrical resistance as well as mechanical impulse resulting from acoustic wave propagation, might cause serious damage. Currently used metallic meshes and foils immersed in composite structures are effective in dissipating lightning charges and generated heat, however, such a solution has numerous disadvantages like increasing mass, problems with adhesion on the metal/polymer interface, complicated manufacturing technology, etc. Therefore, a fully organic conductive composite was developed as an alternative to current solutions. After a lightning strike the developed composite should not only effectively conduct and dissipate the electrical charge and generated heat, but also stop burning, which appears due to very high temperature values in the vicinity of the strike area. In this study, flammability tests were performed for a classic carbon fabric-reinforced composite as well as for the developed conductive polymer and carbon fabric-reinforced composite based on this polymer for comparative purposes, with measurement of the combustion temperature. The obtained results show that the developed composite is characterized by sufficiently low flammability, however, further studies will be focused on further improvement of flame retardancy.

PL

Ochrona odgromowa jest jednym z ważniejszych wymagań strukturalnych stawianych kompozytom lotniczym, odnoszących się do ich integralności oraz trwałości po uderzeniu pioruna. Gdy piorun uderza w klasyczne struktury kompozytowe, ciepło generowane z oporu elektrycznego oraz impuls mechaniczny, wynikający z propagacji fali akustycznej, może spowodować poważne uszkodzenia. Obecnie stosowane metalowe siatki i folie zatopione w strukturach kompozytowych są efektywne w rozpraszaniu ładunków piorunowych i generowanego ciepła, jednak takie rozwiązanie posiada szereg wad, jak wzrost masy, problemy z adhezją na granicy ośrodków metal/polimer, skomplikowana technologia wytwarzania itd. Dlatego został opracowany w pełni organiczny kompozyt przewodzący jako alternatywa dla obecnych rozwiązań. Po uderzeniu pioruna opracowany kompozyt powinien nie tylko efektywnie przewodzić i rozpraszać ładunek elektryczny i generowane ciepło, ale także zatrzymać płonięcie, powstające w wyniku bardzo dużych wartości temperatury w otoczeniu miejsca uderzenia. W niniejszej pracy w celach porównawczych badania palności przeprowadzono dla klasycznego kompozytu wzmacnianego tkaniną węglową oraz opracowanego polimeru i kompozytu wzmacnianego tkaniną węglową na jego bazie z pomiarem temperatury spalania. Otrzymane wyniki wykazały, że opracowany kompozyt charakteryzuje się stosunkowo niską palnością, jednak przyszłe badania będą skupione na dalszej poprawie ognioodporności.

4

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

Katunin A.

Fatigue of Aircraft Structures

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2016

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Iss. 8

49--54

EN

Lightning 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.

5

Concept of a conducting composite material for lightning strike protection

Katunin A., Krukiewicz K., Herega A., Catalanotti G.

Advances in Materials Science

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2016

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Vol. 16, nr 2(48)

32--46

EN

The paper focuses on development of a multifunctional material which allows conducting of electrical current and simultaneously holds mechanical properties of a polymeric composite. Such material could be applied for exterior fuselage elements of an aircraft in order to minimize damage occurring during lightning strikes. The concept introduced in this paper is presented from the points of view of various scientific disciplines including materials science, chemistry, structural physics and mechanical engineering with a discussion on results achieved to-date and further plans of research.