Akustik yalıtım için dokuma kumaş takviyeli katmanlı hibrid kompozit malzemelerin geliştirilmesi
Development of fabric reinforced layered hybrid composite materials for acoustic insulation
Yazar: MUSTAFA ÇAĞATAY YARADANAKUL
Danışman: DOÇ. DR. NAZAN OKUR
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Tekstil Mühendisliği Ana Bilim Dalı / Tekstil Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2020
Konu: Tekstil ve Tekstil Mühendisliği = Textile and Textile Engineering

Özet:
Günümüz dünyasında gürültü insan yaşamını negatif etkileyen önemli sebeplerden biridir. Günlük hayatımızda trafik, çalışma alanımızda ve evlerimizde bulunan teknolojik cihazlar gibi çeşitli sebeplerden ötürü gürültüler oluşmaktadır. Bu gürültüler insanları, psikolojik olarak büyük ölçüde etkilemekte ve bunun sonucu olarak yaşam kalitesi düşmektedir. Bu sebepten ötürü bulunulan ortamın konfor seviyesini artırmak ya da dış çevreyi olumsuz anlamda etkilememek amacıyla binalarda, taşıt araçlarında, ev eşyalarında sesin azaltılması önem taşımaktadır. Günlük yaşamda ve çalışma ortamında gürültünün kontrol edilmesine ilişkin yönetmeliklerin de getirdiği kurallar çerçevesinde akustik yalıtım her geçen gün daha önemli hale gelmektedir.
Dünyada ve ülkemizde insan nüfusunun artışı ve beraberinde artış gösteren ses ve gürültü kirliliğini önlemek ve insanların yaşantılarını daha konforlu bir hale getirmek için kullanılan tekstil malzemelerinin önemi gün geçtikçe artmaktadır. Tekstil malzemelerinden üretilmiş kompozit malzemelerin önemi artmaktadır. Akustik yalıtım için kumaş takviyeli katmanlı hibrid bir kompozit malzemenin geliştirilmesi hedeflenen bu çalışmada cam karbon jüt ve keten kumaşlardan kompozit yapılar oluşturulmuştur.
Çalışmanın başında kalınlıklarının ayarlanması amacıyla test üretimleri gerçekleştirilmiş bu üretimler sonucunda kalınlıklara bakıldıktan sonra ideal kalınlıktaki kompozit malzemelerin asıl üretimleri vakum infüzyon tekniği kullanılarak gerçekleştirilmiştir. Üretilen bu kompozit malzemelerin bir boşluklu kumaş yapısı ile bir araya getirilerek oluşturulan katmanlı hibrid kompozit malzeme yapılarının ses absorbsiyon özellikleri incelenmiştir. Sırası ile yerleri değiştirilerek oluşturulan yapıların ses absorbsiyon özellikleri incelenmiştir.
Öncelikli olarak malzemeler kendi içlerinde 3 katlı olarak incelenmiştir. Ardından değişik sıralı yapılar oluşturularak bu yapıların ses absorbsiyon katsayıları incelenmiştir. Oluşturulan değişik yapı sıralamaları ile malzemeler incelendiğinde ses dalgalarını öncelikli olarak karşılayan yüzey boşluklu kumaş olduğunda ve özellikle yapıdaki boşluklu kumaş sayısı 2 tane olduğunda ses absorbsiyon performanslarının daha yüksek olduğu görülmektedir. Keten ve jüt malzemelerin, boşluklu kumaş ile oluşturulan malzemelerde ses absorbsiyon katsayılarının yapısında cam ve karbon malzemelerinde olduğu yapılar kadar iyi performans ortaya koyduğu gözlemlenmiştir. Akustik yalıtımda kullanılmak amacıyla oluşturulacak hibrid kompozit malzeme yapısında jüt ve keten kumaşlardan oluşturulmuş kompozit yapımında kullanılabileceği görülmüştür.
Bu çalışma; İTÜ Bilimsel Araştırma Projeleri Birimince desteklenmiştir (Proje numarası: MYL-2018-41882)

Abstract:
In today's world, noise is one of the important reasons that negatively affect human life. Noises occur for various reasons such as traffic in our daily life, technological devices in our work area and homes. These noises greatly affect people psychologically and as a result, their quality of life decreases. For this reason, in order to increase the comfort level of the environment or not to adversely affect the external environment, it is important to reduce the noise in buildings, vehicles and household goods. High sound levels can cause adverse physiological and psychological effects such as hearing damage on human health, increased stress, lack of concentration and disturbing sleep patterns. Acoustic insulation is becoming more and more important every day within the framework of the rules set by the regulations for controlling noise in daily life and working environment.
Acoustic materials are used in buildings and construction, transportation and industrial applications. The use of acoustic textiles worldwide is increasing rapidly due to increasing application areas, technological developments, increased demand and tighter regulations regarding noise regulation. Population growth, more stringent regulations are being implemented in the construction of new buildings, increased environmental concerns and sustainability are among the factors that increase acoustic applications. In the future, it is anticipated that acoustic materials will include industrial applications in areas such as oil, gas and energy production.
When the sound energy hits a surface, it can be reflected, transmitted or absorbed. Materials used to effectively reduce sound, in other words, acoustic insulation materials are materials that can absorb most of the sound energy falling on them or reduce the sound energy passing through the material. In order to control the sound; materials that absorb sound energy, materials that dissipate the energy in the form of heat, materials that block the transmission of sound, materials that block the transmission of sound, materials that physically block the transmission of sound energy, can be used.
In most acoustic insulation materials, sound is reduced by absorbing sound energy. For this purpose, porous structures and fibrous structures are preferred. Although foam, rock wool and glass wool are among the most used materials to reduce noise, they have been; recently, it is observed that natural or synthetic textile fibers, woven and knitted fabrics, non-woven textile surfaces and acoustic insulation materials are increasingly involved. Instead of solid and especially heavy materials, thin and light textile materials and composite structures produced using these materials find application in the field of acoustic insulation.
The importance of textile materials, which are used to stop the increase of the human population in the world and in our country and to increase the noise and noise dirtiness and to make people's lives more comfortable, is increasing day to day. Depending on the application area and expected performance, textile materials used
in acoustic applications can be woven fabrics, knitted fabrics, nonwoven surfaces or textile-reinforced composite materials. Woven and knitted fabrics can also take place in acoustic applications in three dimensions (3D). Regarding the knitted fabrics, both weft and warp knitted fabric structures cannot provide sufficient sound barrier properties due to their limited thickness and density. However; spacer fabrics are more effective structures in terms of sound absorption. Spacer fabrics are defined as fabric structures consisting of two layers of knitted structure, in which these layers are usually bonded together by a monofilament binding thread. The fabric thickness depends on the length of the connecting yarns. Spacer fabrics are produced in warp knitting machines. Such 3D knitted fabric structures are less flexible. At the same time, they are less costly and unchanged due to moisture fluctuations. Research on the use of 3D fabric structures in acoustic applications has recently been undertaken.
In addition, the importance of composite materials produced from textile materials is increasing, too. Composite materials are materials created by combining two or more materials that are macroscopically independent from each other. Composite materials are used where properties such as high strength, forming a rigid structure, lightness, heat resistance, high fatigue resistance are desired. These properties are developed in accordance with the area where the composite material is needed. During this production, a matrix element is used in the structure of the composite material, in addition, a reinforcing element is used. Due to their structure, the use of composite materials has increased especially in areas where lightness and durability are desired. Textile reinforced composites are often characterized by high specific strength and better stiffness compared to other materials. It provides the desired mechanical properties to the final engineering parts, including fiber, lightness, high stiffness in the direction of reinforcing fibers and relatively easy forming processes as reinforcing material.
Both natural and synthetic fibers and recycled materials are used to produce textile-based acoustic materials. These materials are in the form of a porous absorber or panel absorber for acoustic applications. Sometimes textile-based acoustic materials are coated with special chemicals to improve various performance characteristics, depending on the required applications. Natural fiber composites (with thermoplastic or thermoset) are used by many automobile manufacturers and for acoustic purposes in other fields. Composites have excellent properties such as low weight, high strength and hardness; this makes them possible for a variety of technical applications, including acoustics.
Due to the growing environmental concerns and demands of the legislative authorities, the use of conventional composites is reduced by using synthetic fiber materials such as glass, carbon or aramid. On the other hand, due to environmental friendliness and biodegradability, composites of natural fibers are widely used in many technical applications. There are also other advantages, such as low cost and enhanced security. Natural fiber reinforced composites offer more recycling capacity than traditional polymer composites. Various researches have been done on composite materials for acoustic applications. In the production of composite materials, hybrid structures formed by combining two or more types of reinforcing elements or layers can also be used in acoustic applications. The performance of these structures in acoustic applications varies depending on the order of the layers.
Today, it is aimed to prevent the noise pollution, which has become a major problem in our world and in our country, and to use hybrid composite materials with sound-
reducing effects in the isolation of people's living spaces so that people can get away from this pollution a little and have a more comfortable life. In this study, which aims to develop a fabric reinforced layered hybrid composite material for acoustic insulation, composite structures were produced. Plain woven fabrics produced from linen fiber and made of jute fiber were used in the production of composite plates reinforced with woven fabric. In addition, plain woven fabric made of glass fiber and plain woven fabric made of carbon fiber were used as reinforcing material in the production of benchmark samples. At the beginning of the study, test productions were carried out in order to adjust the thickness, after looking at the thicknesses, the actual productions of composite materials with ideal thickness were made using the vacuum infusion technique. The sound absorption properties of layered hybrid composite materials constructed by combining these produced composite materials with a spacer fabric structure were examined. The sound absorption properties of the structures obtained by changing their places in the layered structure, respectively, were examined.
When the results obtained from the sound absorption tests were examined, it was observed that:
1. When the surfaces that meet the sound waves coming to the surface are selected as the fabrics with voids and the number of surfaces with this selected voiced fabric is determined as 2, the results obtained have been observed to be better at high frequencies.
2. However, when spacer fabrics are selected between a single layer and placed between two woven fabrics, the results have been shown to yield as good results as hybrid structures created with 2 spacer fabrics at high frequencies.
3. In addition, hybrid structures (especially with jute and linen fabrics) obtained by using spacer fabric and different composite surfaces were found to have very good results at high frequencies.
4. Finally, when all the results are examined, it is seen that the spacecr fabrics in the hybrid composite structures to be produced for use for sound insulation and fabrics made from natural fibers such as jute and linen are used in the selection of the materials to be used when creating the composite structure.
All these results reveal that composite hybrid structures are preferable in every field where composite materials are preferred for acoustic insulation. It is of great importance in terms of sustainability that the materials used in the structure are preferred from natural materials and that these materials are recyclable.
In order to reduce the thickness of the structure in the future projects that can be made after this study, when epoxy and resin are applied, natural materials that can create a composite structure by absorbing less amount of epoxy resin can be used. However, by reducing the spacer fabric thickness used, it is possible to reduce the thickness of the structure.
In addition, it is thought that selecting recycled materials in the production of materials to be used in the material structure can yield good results in terms of both reducing the damage to the nature and reducing the production costs.
Studies on hybrid materials created by combining different types of structures for the use of composite materials in acoustic insulation applications have been quite
limited. Thus, the present study contributed to the literature regarding the use of textile reinforced laminated hybrid composite materials in acoustic applications.
This work was supported by the Research Fund of Istanbul Technical University (Project Number: MYL-2018-41882)