Composites

Composites are made up of two constituent materials; a matrix and reinforcement. The majority of composites use a polymer matrix material or resin. Reinforcement materials are often fibres but may be ground minerals. Typically, lay up results in a product containing 60% resin and 40% fibre, while vacuum infusion produces product with 40% resin and 60% fibre. The strength of the final product is greatly dependent on this ratio.Composites are anisotropic and characterized by Young's Modulus, Shear Modulus and Poisson's ratio. The math requires a second order tensor and up to 21 material property constants. For orthogonal isotropy, there are three different material property constants for each ratio—a total of 9 constants to describe the relationship between forces/moments and strains/curvatures. Designing and testing composites can be challenging. Common resins include epoxy, polyester, vinylester and Shape memory polymer (SMP) resin. Common fibers includes fiberglass, carbon fiber, and Kevlar. Fiber-reinforced composite materials include short fiber-reinforced materials and continuous fiber-reinforced materials which are used in layered or laminated structures.

Types of Composites

• Thermoplastic resin composite, short fibre thermoplastics, long fibre thermoplastics and long fibre-reinforced thermoplastics
• Aramid fibre and carbon fibre in epoxy resin matrixes
• Shape memory polymer composites are formulated using fibre or fabric reinforcement and shape memory polymer resin as the matrix
• Reinforced Concrete consists of loose stones (aggregate) held with a matrix of cement with metal cables added to tension the concrete
• Metal matrix composites (MMC) use metal fibres to reinforce other metals

Ceramic matrix composites are for fracture toughness, not strength. Applications include bone (hydroxyapatite reinforced with collagen fibres), Cermet (ceramic and metal) and concrete. CMC includes asphalt concrete, mastic asphalt, mastic roller hybrid, dental composite, syntactic foam, mother of pearl and composite armour for military applications.

Engineered wood composites include wood fibre board, plywood, oriented strand board, wood plastic composite, Pykrete, Plastic-impregnated or laminated paper or textiles, Arborite, Formica, and Micarta. Mallite also generates low-weight, high rigidity materials.

Composite layup designs include curing the prepreg with various honeycombs or foam called a sandwich structure. This is a more common layup process for the manufacture of radomes, doors, cowlings, and non-structural parts.

Mechanical Testing Since composites are used to improve stiffness and strength with lighter weight, they are employed in critical applications that include military aircraft, commercial aircraft, aerospace, etc etc. And so testing is more important to confirm design assumptions. Testing is especially important in these applications. The variations in fibres and matrices that are available and the mixtures that can be made with blends leave a very broad range of properties to design for. The best known failure of ceramic matrix composite occurred when the carbon-carbon composite tile on the leading edge of the wing of the Space Shuttle Columbia fractured when impacted during take-off.

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• Tensile Testing of Plastics & Composites | Equipment for ASTM D638
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• Climbing Drum Peel Tests with Sandwich Specimens
• Fracture Toughness Test Equipment for Engineered Composites
• Fatigue Testing of Ceramic Matrix Composites
• Fatigue Test Equipment for Polymer Matrix Composites
• Fatigue Test Machines for Honeycomb Composites
• Fatigue Testing Metal Matrix Composites
• Plastic Composite Compression Testing Accessories
• Flexural Test of Plastics & Composites using Three and Four Point Bend Fixtures
• Stress Strain Image Correlation Test | Engineered Composites Spotlight
• Fiber Reinforced Composites Test Equipment
• Composites Fatigue Test Machines and Fixtures
• Composites Fracture Toughness Test Equipment
• Fiber Composites Tensile Test Equipment
• Composites Fastener Pull-Through Test Equipment
• Composites Flexural Bend Testing Equipment
• Composites Shear Test Equipment
• Ceramic Matrix Composites Fatigue Test Equipment
• Honeycomb Composite Fatigue Test Equipment
• Metal Matrix Composites Fatigue Test Equipment
• 3 and 4 Point Flexural Bend Test Equipment for Composites
• Composites Bearing Response Test Equipment
• Plastics Composites Compression Test Equipment
• Composite Materials Open-Hole Strength Test Equipment
• 45 Degree Tension Test of In-Plane Shear Modulus and Strength
• Apparent Interlaminar Shear Strength by Short-Beam Method
• Polymer Matrix Composite Materials Tensile Testing
• Aramid Yarn Tensile Testing
• Fiber Reinforced Plastic Composites Tensile Tests
• Composite Laminate Tensile Testing in an Environmental Chamber
• Single Fiber Carbon Tensile Test Equipment

Applicable Standards

• ASTM C1499 Equibiaxial Flexural Ceramics Test Equipment
• ASTM C393 Flexural Sandwich Composites Test Equipment
• ASTM D2343 Tensile Glass Fiber Strands Yarns Rovings Testing Equipment
• ASTM D3039 Tensile Testing for Advanced Composite Materials
• ASTM D3479 Tension-Tension Fatigue of Polymer Matrix Composite Materials
• ASTM D3518 In-Plane Shear of Polymer Matrix Composite Materials by Tensile Test
• ASTM D4255 In-Plane Rail Shear of Polymer Matrix Composite Materials
• ASTM D5379 Shear Properties of Composite Materials by the V-Notched Beam Method
• ASTM D5961 Polymer Matrix Composite Laminate Bearing Strength Test Equipment
• ASTM D6272 Four Point Flexural Bend Test Machine for Plastics and Insulating Materials
• ASTM D6415 Curved Beam Strength Test Equipment for Fiber-Reinforced Composites
• ASTM D6416 Flexural Sandwich Composite Plate Composite Test Machine
• ASTM D7137 Compressive Residual Strength Test Equipment for Damaged Polymer Matrix Composite Plates
• ASTM D7205 Tensile Tests of GFRP Matrix Composite Bars
• ASTM D7264 Flexural Test Equipment for Polymer Matrix Composite Materials
• ASTM D7332 Fastener Pull-Through Resistance of a Fiber-Reinforced Polymer Matrix Composite
• ISO 15024 Interlaminar Fracture Toughness of Plastic Composites Test Machines
• ISO 15490 Fine Ceramics Tensile Strength