Oksetik (auxetıc) kompozit malzemelerin geliştirilmesi
Küçük Resim Yok
Tarih
2024
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Bursa Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/embargoedAccess
Özet
Son yıllarda eklemeli imalat (Eİ) olarak hayatımızda yer alan üç boyutlu yazıcı teknolojisi hızla yaygınlaşmakta ve gelişmektedir. Uzay, savunma, havacılık, spor, otomotiv, gıda, biyomedikal, inşaat ve tıp gibi alanlarda hızlı bir şekilde yer bularak son zamanların en yaygın kullanılan teknolojileri arasındadır. Üç boyutlu yazıcıların farklı tipleri ve çalışılabilecek geniş malzeme yelpazesiyle metal ve seramik malzemelerin yanısıra termoplastik malzemelerinde yaygın kullanımıyla bilimsel araştırmalarda farklı konuların ele alınması mümkün olmuştur. Üç boyutlu yazıcılarda PLA (Polilaktik Asit) malzemesi yaygın bir şekilde kullanılmaktadır. PLA termoplastik polimerler olduğu için geri dönüştürülebilir malzemedir. PLA, biyo çözünür özelliği ile medikal ve ambalaj alanında yaygın bir şekilde kullanılmaktadır. Bu çalışma kapsamında, sandviç kompozitlerde yenilikçi çekirdek yapı tasarımı ve üretimi gerçekleştirmek için eklemeli imalat yöntemi kullanılmıştır. Pozitif Poisson oranına sahip oksetik olmayan geleneksel Bal Peteği yapısı ile negatif Poisson oranına sahip Yeniden Girintili ve tasarımda modifikasyon gerçekleştirilerek Geliştirilmiş Yeniden Girintili çekirdek tasarımı üretilmiştir. Üç farklı tasarıma sahip yapılar için eklemeli imalat yöntemi ile katmanlı üretim gerçekleştirilmiştir. Çekme, üç nokta eğme ve basma testi için ASTM standartlarına uygun numuneler üretilmiştir. 3B baskı ile üretilen basma ve üç nokta eğme numunelerinin karbon elyaf ve epoksi malzemeleriyle çekirdek yapının alt ve üst yüzeyleri kaplanması sağlanmıştır. Böylece sandviç kompozit yapı oluşturulmuştur. Gerçekleştirilen testlere göre numunelerin mekanik özellikleri ve farklı tasarıma sahip çekirdek hücrelerin Poisson oranları incelenmiştir. Literatürde gerçekleştirilen çalışmalara göre negatif Poisson oranına sahip oksetik özellikteki Yeniden Girintili tasarımların geleneksel pozitif Poisson oranına sahip oksetik olmayan Bal Peteği tasarımına göre daha üstün üç nokta eğme ve basma dayanım değeri olduğu tespit edilmiştir. Yapılan bu çalışmanın sonucunda üç nokta eğme testine göre Geliştirilmiş Yeniden Girintili sandviç yapıda geleneksel Bal Peteği ve Yeniden Girintili sandviç yapıya göre daha yüksek mukamevete sahip olduğu gözlemlenmiştir. Üç nokta eğme testinde Bal Peteği sandviç yapı 142,15 MPa, Yeniden Girintili sandviç yapı 150,68 MPa ve Geliştirilmiş Yeniden Girintili sandviç yapı 160,83 MPa değerlerine ulaştığı görülmektedir. Gerçekleştirilen basma testine göre Geliştirilmiş Yeniden Girintili sandviç yapıda geleneksel Bal Peteği ve Yeniden Girintili sandviç yapıya göre daha yüksek mukavemete sahip olduğu gözlemlenmiştir. Basma testinde Bal Peteği sandviç yapı 88,7 MPa, Yeniden Girintili sandviç yapı 114,66 MPa ve Geliştirilmiş Yeniden Girintili sandviç yapı 125 MPa değerlerine ulaştığı görülmektedir. Gerçekleştirilen bu çalışma kapsamında en yüksek üç nokta eğme ve basma dayanımına sahip Geliştirilmiş Yeniden Girintili sandviç yapı olduğu hem deneysel, hem de analiz verilerine göre doğrulanmıştır. En düşük üç nokta eğme ve basma dayanımına sahip tasarım ise geleneksel Bal Peteği sandviç kompozit yapısına ait olduğu tespit edilmiştir.
In recent years, three-dimensional printing technology, which has become part of our lives as additive manufacturing (AM), is rapidly becoming widespread and developing. It is among the most widely used technologies of recent times, rapidly finding a place in fields such as space, defense, aviation, sports, automotive, food, biomedical, construction and medicine. With the different types of three-dimensional printers and the wide range of materials that can be worked with, and the widespread use of thermoplastic materials as well as metal and ceramic materials, it has become possible to address different topics in scientific research. PLA (Polylactic Acid) material is widely used in three-dimensional printers. Since PLA is thermoplastic polymers, it is a recyclable material. PLA is widely used in the medical and packaging fields with its biodegradable feature. Within the scope of this study, additive manufacturing method was used to realize innovative core structure design and production in sandwich composites. A non auxetic traditional Honeycomb structure with a positive Poisson ratio and a Re-entrant core design with a negative Poisson ratio and an Improved Re-entrant core design by modification of the design were produced. Additive manufacturing was carried out using the additive manufacturing method for structures with three different designs. Samples complying with ASTM standards were produced for tensile, three-point bending and compression tests. The upper and lower surfaces of the core structure were covered with carbon fiber and epoxy materials of the compression and three point bending samples produced by 3D printing. Thus, a sandwich composite structure was created. According to the tests performed, the mechanical properties of the samples and the Poisson ratios of the nuclear cells with different designs were examined. According to studies carried out in the literature, it has been determined that auxetic Re-entrant designs with negative Poisson's ratio have superior three-point bending and compressive strength values than the traditional non-auxetic Honeycomb design with positive Poisson's ratio. As a result of this study, it was observed that the Improved Re-entrant sandwich structure had higher strength than the traditional Honeycomb and Re-entrant sandwich structure, according to the three-point bending test. In the three-point bending test, it is seen that the Honeycomb sandwich structure reaches 142.15 MPa, the Re-entrant sandwich structure reaches 150.68 MPa and the Improved Re-entrant sandwich structure reaches 160.83 MPa. According to the compression test performed, it was observed that the Improved Re entrant sandwich structure had higher strength than the traditional Honeycomb and Re entrant sandwich structure. In the compression test, it is seen that the Honeycomb sandwich structure reaches 88.7 MPa, the Re-entrant sandwich structure reaches 114.66 MPa and the Improved Re-entrant sandwich structure reaches 125 MPa. Within the scope of this study, it has been confirmed according to both experimental and analysis data that it is an improved re-entrant sandwich structure with the highest three-point bending and compressive strength. It was determined that the design with the lowest three-point bending and compressive strength belonged to the traditional honeycomb sandwich composite structure.
In recent years, three-dimensional printing technology, which has become part of our lives as additive manufacturing (AM), is rapidly becoming widespread and developing. It is among the most widely used technologies of recent times, rapidly finding a place in fields such as space, defense, aviation, sports, automotive, food, biomedical, construction and medicine. With the different types of three-dimensional printers and the wide range of materials that can be worked with, and the widespread use of thermoplastic materials as well as metal and ceramic materials, it has become possible to address different topics in scientific research. PLA (Polylactic Acid) material is widely used in three-dimensional printers. Since PLA is thermoplastic polymers, it is a recyclable material. PLA is widely used in the medical and packaging fields with its biodegradable feature. Within the scope of this study, additive manufacturing method was used to realize innovative core structure design and production in sandwich composites. A non auxetic traditional Honeycomb structure with a positive Poisson ratio and a Re-entrant core design with a negative Poisson ratio and an Improved Re-entrant core design by modification of the design were produced. Additive manufacturing was carried out using the additive manufacturing method for structures with three different designs. Samples complying with ASTM standards were produced for tensile, three-point bending and compression tests. The upper and lower surfaces of the core structure were covered with carbon fiber and epoxy materials of the compression and three point bending samples produced by 3D printing. Thus, a sandwich composite structure was created. According to the tests performed, the mechanical properties of the samples and the Poisson ratios of the nuclear cells with different designs were examined. According to studies carried out in the literature, it has been determined that auxetic Re-entrant designs with negative Poisson's ratio have superior three-point bending and compressive strength values than the traditional non-auxetic Honeycomb design with positive Poisson's ratio. As a result of this study, it was observed that the Improved Re-entrant sandwich structure had higher strength than the traditional Honeycomb and Re-entrant sandwich structure, according to the three-point bending test. In the three-point bending test, it is seen that the Honeycomb sandwich structure reaches 142.15 MPa, the Re-entrant sandwich structure reaches 150.68 MPa and the Improved Re-entrant sandwich structure reaches 160.83 MPa. According to the compression test performed, it was observed that the Improved Re entrant sandwich structure had higher strength than the traditional Honeycomb and Re entrant sandwich structure. In the compression test, it is seen that the Honeycomb sandwich structure reaches 88.7 MPa, the Re-entrant sandwich structure reaches 114.66 MPa and the Improved Re-entrant sandwich structure reaches 125 MPa. Within the scope of this study, it has been confirmed according to both experimental and analysis data that it is an improved re-entrant sandwich structure with the highest three-point bending and compressive strength. It was determined that the design with the lowest three-point bending and compressive strength belonged to the traditional honeycomb sandwich composite structure.
Açıklama
25.01.2025 tarihine kadar kullanımı yazar tarafından kısıtlanmıştır.
Anahtar Kelimeler
ngineering Sciences, Polimer Bilim ve Teknolojisi, olymer Science and Technology, Mühendislik Bilimleri
