Composite Materials Used in Spacecraft

Turkchem 14 Jul 2020 45 5 dk okuma

TURKCHEM

Material science holds great importance for every industrial sector. One of the areas receiving the most materials research and investment is the aerospace and aviation industry. Aircraft must counteract the gravitational force (weight) acting upon them using their own load-bearing elements (wings in aircraft, rocket motors in spacecraft). The weight of an aircraft consists of four components: structural weight, payload weight (passengers/cargo in commercial aircraft, ammunition in military aircraft), engine weight, and fuel weight. Composite materials used in aviation stand out as materials that deliver the best results along the strength-to-weight axis. A "composite material" is defined as a new material produced by combining two or more materials with different physical properties using specific methods, and which possesses more advanced properties than those individual materials. Composite materials generally consist of two different layers: the reinforcement material that carries the load, and the matrix that holds this material together and provides support. Composites used in aerospace structures have many advantages and disadvantages.

Advantages:

• Much lighter than conventional materials, • High fatigue resistance, • High fire resistance, • High corrosion resistance, • Can be produced in complex shapes, • Can be produced in large sections.

Disadvantages:

• More expensive than conventional materials, • Strength properties are not equal in all directions, • Depends on the orientation of reinforcement material placement, • In some cases, maintenance is more difficult, • Material quality depends on production quality, • No standard quality exists.

Major Types of Composites Used in Aerospace and Aviation

1- CFRP (Carbon-fibre Reinforced Polymer) CFRP is among the commonly used composites. Carbon-fiber reinforcement material is present within the polymer matrix phase. CFRP is one of the most widely used composites in spacecraft. The strength-to-weight ratio and its ability to maintain thermal balance over a wide temperature range are important characteristics. It is used in spacecraft coatings, articulated load-bearing arms, antenna reflectors, solar panel equipment, and optical platforms. Recently, it is also being used in main structural elements of spacecraft. The first of these applications is spacecraft. The United States space shuttle uses graphite-epoxy composite for the equipment bay door cover and remote transmission arm, epoxy matrix composite in the solid rocket motor section, and polyamide matrix composite in the thruster tail and wings. Carbon fiber polymer matrix composites are also used in satellite structures and solar panels. In many space applications, aerospace-type carbon fibers (tensile strength 3550 MPa, tensile modulus 235 GPa) are used together with multifunctional epoxy matrix bonded at 177°C. Carbon fibers offer many advantages due to their high specific strength, resistance to torsion and impact damage, and corrosion resistance. 2- GFRP (Glass-fibre Reinforced Polymer) GFRP is a widely used composite material type like CFRP. Glass-fiber reinforcement material is present within the polymer matrix phase. Together with CFRP, it is used in passenger aircraft wings, at wing-fuselage joints, and on antenna covers. In the industry, it was first used on rocket antenna covers. In spacecraft, it is used in some antenna reflectors and where thermal insulation is important. 3- Shape Memory Composites Bendable/foldable under certain conditions, yet capable of returning to their original shape when suitable conditions are provided. For example, they can be bent in warm air and return to their original form when the air cools. Particularly in spacecraft, they enable more efficient packing into confined spaces. An example exists on the International Space Station. A foldable solar panel opens and deploys thanks to shape memory composite technology. This technology has provided considerable space savings in launch and deployment.

4- Honeycomb Composites

Honeycomb sandwich structure composites represent one of the most valuable structural engineering innovations in the composite industry. Widely used in aviation and other industrial sectors, they offer advantages and benefits over other materials in terms of very low weight, strength, and reduced manufacturing costs. Matrix Materials The matrix forms the primary component of the two important elements of composite material. It contributes to the composite material by: • Transferring forces to the fibers and ensuring their uniform distribution, • Protecting fibers from environmental effects and impacts, • Increasing the toughness of the composite material, • Preventing crack formation in composites or halting crack propagation. 1. Plastic Matrix Materials (Polymers) • Thermosets, • Thermoplastics, • Elastomers.

2. Metal Matrix Materials (Aluminum, titanium, magnesium, etc.)

3- High Temperature Matrices (Ceramics) Structural Components of Polymer Matrix Composites Matrices Used • Thermosets • Thermoplastics Fibers Used • Glass Fibers • Carbon Fibers • Aramid Fibers

Current Developments

Many panels have been held under the Science and Technology Strategies Project, one of which is the Defense, Aviation and Space Industry Panel (SHUP). In 2004, within the framework of all these panel reports submitted to the Science and Technology High Council (BTYK), the draft "National Science and Technology Policies 2003–2023 Strategy Document" was created, and the technology policies, visions and targets of our country were clarified. In SHUP, critical technologies and their sub-technology areas were identified to achieve the targets. Composite materials became an indispensable part of the aviation sector following the first successful flight achieved by the Wright brothers in 1903 (Soutis, 2005). Starke and Staley (1996) stated that in early aircraft, the strength-to-weight ratio (specific strength) was the most important criterion in material selection, and for this reason composite materials were used. However, changing needs over time revealed that composite materials needed to possess additional properties. For example, in the 1990s, designers began to consider improved damage tolerance and corrosion resistance in composite materials, taking into account aircraft fleets that had been in inventory for long periods and were aging (Starke and Staley, 1996). Some aircraft worldwide containing composite materials include: F–14, F–15, F-16, F/A–18, AV–8B, Eurofighter (EFA), Advanced Jet Fighter (AJF), Joint Strike Fighter (JSF–F35), F–117 Black Hawk, Beech Aircraft Starhip, Pacific Theater B29, APACHE, B–2 Bomber. The United States National Aeronautics and Space Administration (NASA, 1987) demonstrated that despite the high manufacturing cost of composite materials, the total cost is lower because they require fewer labor hours. NASA has also developed certain concepts for weight reduction. The non-autoclave (NONA) primary composite structures concept was introduced for lighter materials (Piascik et al., 2012). NASA (Piascik et al., 2012; NASA, 2015) included the following technologies related to composite materials for lightweight structures in its technology roadmap reports: • Out-of-autoclave (OOA) composites, • Hybrid laminates, • Tailorable materials, • Advanced propulsion materials (for example, CMC, etc.), • Multifunctional structures, • Self-healing materials.