Aviyonik sistemlerde elektromanyetik kalkanlama ve hava araçları için karbon fiber kompozit malzeme geliştirilmesi
Yükleniyor...
Dosyalar
Tarih
2021
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Bursa Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Havacılık ve savunma sanayinde artan rekabet, hava araçlarında kullanılan malzemelerin hem elektromanyetik girişim (EMI) kalkanlama özelliğine hem de üstün mekanik özelliklere sahip olmasını gerektirmektedir. Ayrıca, uçakların hafif malzemeler ile tasarlanması performanslarını arttırmak için önemlidir. Dolayısıyla, karbon fiber gibi hafif ve üstün mekanik özelliklere sahip takviye malzemeleri kullanarak, elektromanyetik kalkanlama açısından verimli kompozit malzemelerin geliştirilmesi güncel bir konudur. Bu tez çalışmasında elektromanyetik dalgaların aviyonikler üzerindeki olumsuz etkilerini azaltan bir karbon fiber kompozit malzemenin geliştirilmesi amaçlanmıştır. Yapılan deneysel çalışmada, matris malzemesi olarak epoksi reçine ve takviye malzemesi olarak; tek yönlü ve çift yönlü karbon fiber kumaşlar kullanılmıştır. Ayrıca, üretilen bazı kompozitlerde daha yüksek kırılma noktası ve esneklik elde etmek için çift yönlü cam fiber kumaşlar takviye edilmiştir. Toplam sekiz kompozit plaka, elle yatırma yöntemi ile farklı oryantasyon ve katman sayılarında iki set olarak üretilmiştir. Birinci set ve ikinci set malzemelerin karbon fiber hacim oranı sırasıyla %45-%50 ve %35-%40 aralığındadır. Üretilen kompozit plakaların; oryantasyon açısı, katman sayısı ve fiber kumaş tipi gibi parametreleri için elektromanyetik dalga kalkanlama karakteristikleri incelenerek iyi kalkanlama değerleri veren kompozit malzemeler belirlenmiştir. Ölçüm için; Aaronia marka DFG 4060 model dalga jeneratörü, HF 60105 model spektrum analizör ve iki directional anten kullanılarak, 900 MHz ile 6000 MHz aralığında malzemelerin elektromanyetik kalkanlama etkinlikleri (EKE) ölçülmüştür. Çalışılan frekans aralığında 62.13 dB'e kadar EKE elde edilmiştir. Bu değer, literatürde iyi kalkanlama seviyesi olarak kabul edilmektedir. Dahası, ölçüm sonuçlarına göre; 0°'ye nazaran, karbon fiberin oryantasyon açısı 90° olduğunda EKE'nin çok daha yüksek olduğu gözlemlenmiştir. EKE'ye etki eden bir diğer parametre karbon fiber kumaşın tek yönlü veya çift yönlü olmasıdır çünkü çift yönlü kumaşın EKE'yi arttırdığı gözlemlenmiştir. Ayrıca, katman sayısının EKE üzerinde oryantasyon açısından daha az etkiye sahip olduğu saptanmıştır. Simülasyon kısmında, COMSOL Multiphysics yazılımıyla alüminyum, demir, FR-4 ve karbon fiber kompozit malzeme için elektrik alan büyüklükleri hesaplanarak EKE gözlemlenmiştir. Son olarak; F-16, F-22 ve F-117 uçak modelleri ile gerçekleştirilen simülasyonlarda, karbon fiberin gizlilik teknolojisi açısından hava araçlarında kullanılabileceği gösterilmiştir.
Increasing competition in aeronaustics and defence industry requires that materials used in aircrafts have both electromagnetic interference (EMI) shielding and excellent mechanical properties. In order to improve performances of airplanes, it is also important that they are designed with light materials. Therefore, in terms of electromagnetic shielding, it is a current topic that efficient composite materials are developed by using light reinforcement materials with excellent mechanical properties like carbon fiber. In this thesis, it was aimed that a carbon fiber composite material, which decreases negative impacts in avionics of electromagnetic waves was developed. In the experimental study performed, epoxy resin as the matrix material and unidirectional and bidirectional carbon fiber fabrics were used as the reinforcement material. Bidirectional glass fibre fabrics were also reinforced to get a higher breaking point and more flexibility in some composites manufactured. A total of eight composite laminates were manufactured as two sets in different orientations and number of plies by hand lay-up method. Carbon fiber volume fractions of the first and second set materials are in the ranges of 0.45-0.50 and 0.35-0.40, respectively. Composite materials that provide good values of shielding were determined by analyzing electromagnetic wave shielding characteristics for parameters like orientation angle, number of plies and fiber fabric type of the composite laminates. Electromagnetic shielding effectiveness (EMSE) values of the materials were measured in the frequency range between 900 and 6000 MHz, using Aaronia DFG 4060 wave generator, HF 60105 spectrum analyzer and two directional antenna. In the proposed frequency range, EMSE up to 62.13 dB was achieved. This value is accepted in the literature as a good level of shielding. Moreover, according to measurement results, it was concluded that EMSE was very higher when the orientation angle of the carbon fiber was 90°, as compared to 0°. Another parameter that affects EMSE is whether the carbon fiber fabric used is unidirectional or bidirectional because it was observed that the bidirectional fabric increased EMSE. In addition, it has been determined that the number of plies has less effect on EMSE than the orientation angle. In simulation part, EMSE was observed calculating electric field strengths for aluminium, iron, FR-4 and carbon fiber composite material by COMSOL Multiphysics software. Finally, in simulations carried out with F-16, F-22 and F-117 airplane models, it was shown that carbon fiber could utilized in aircrafts in terms of stealth technology.
Increasing competition in aeronaustics and defence industry requires that materials used in aircrafts have both electromagnetic interference (EMI) shielding and excellent mechanical properties. In order to improve performances of airplanes, it is also important that they are designed with light materials. Therefore, in terms of electromagnetic shielding, it is a current topic that efficient composite materials are developed by using light reinforcement materials with excellent mechanical properties like carbon fiber. In this thesis, it was aimed that a carbon fiber composite material, which decreases negative impacts in avionics of electromagnetic waves was developed. In the experimental study performed, epoxy resin as the matrix material and unidirectional and bidirectional carbon fiber fabrics were used as the reinforcement material. Bidirectional glass fibre fabrics were also reinforced to get a higher breaking point and more flexibility in some composites manufactured. A total of eight composite laminates were manufactured as two sets in different orientations and number of plies by hand lay-up method. Carbon fiber volume fractions of the first and second set materials are in the ranges of 0.45-0.50 and 0.35-0.40, respectively. Composite materials that provide good values of shielding were determined by analyzing electromagnetic wave shielding characteristics for parameters like orientation angle, number of plies and fiber fabric type of the composite laminates. Electromagnetic shielding effectiveness (EMSE) values of the materials were measured in the frequency range between 900 and 6000 MHz, using Aaronia DFG 4060 wave generator, HF 60105 spectrum analyzer and two directional antenna. In the proposed frequency range, EMSE up to 62.13 dB was achieved. This value is accepted in the literature as a good level of shielding. Moreover, according to measurement results, it was concluded that EMSE was very higher when the orientation angle of the carbon fiber was 90°, as compared to 0°. Another parameter that affects EMSE is whether the carbon fiber fabric used is unidirectional or bidirectional because it was observed that the bidirectional fabric increased EMSE. In addition, it has been determined that the number of plies has less effect on EMSE than the orientation angle. In simulation part, EMSE was observed calculating electric field strengths for aluminium, iron, FR-4 and carbon fiber composite material by COMSOL Multiphysics software. Finally, in simulations carried out with F-16, F-22 and F-117 airplane models, it was shown that carbon fiber could utilized in aircrafts in terms of stealth technology.
Açıklama
Anahtar Kelimeler
Aviyonik sistem, Avionic system, Elektromanyetik ekranlama, Electromagnetic shielding, Kompozit malzemeler, Composite materials, Radar kesit alanı, Radar cross section
