Characteristics of FRP composites
Fibre Reinforced Plastic (FRP) Composites bring enormous benefits to architecture, infrastructure, rail, automotive, aviation, aerospace, marine, defense, and many other industries. Their unique characteristics make them suited for a wide range of applications.
FRP materials are one of the strongest commercial materials available. Pound for pound, FRP is stronger in many ways than conventional construction materials. FRP’s toughness allows thin sections to be used; stiffness can be acquired by using structural core materials, without substantially increasing weight.
Unlike metals, FRP materials do not suffer from corrosion/rusting. Materials fabricated from FRP have a longer service life in corrosive environments and perform extremely well in damp environments or even submerged in fresh and salt water. Durability FRP products have weathered climate extremes since their introduction during World War II. As a result, FRP architectural parts can often reduce long-term maintenance costs when compared to many traditional materials.
A single FRP structure can replace an assembly of many parts and fasteners. This feature saves time, reduces assembly costs, and has given rise to the “cascade effect” of benefits for the user: For example, lighter equipment, smaller work crews, and lighter supporting structures can be used during installation. Light transmission FRP panels can be made translucent. This is a unique property among structural materials. FRP components can simultaneously provide structure and enclosure, while providing natural or artificial light.
Low thermal conductivity FRP performs extremely well in harsh environments including subzero to high ambient temperatures. Composite materials do not easily thermally conduct; thus they provide excellent insulation. FRP composite products can be found in building doors, panels, and windows for extra protection from severe weather. They perform well in tropical as well as arctic regions.
FRP systems can be designed to meet all the reaction-to-fire requirements mandated in the International Building Code sections related to interior finish, light-transmitting materials, and external assemblies.
Most glass-fiber-based FRP composites are transparent to radar and radio frequencies. This attribute enables composite products to be used as decorative canopies or enclosures, designed to hide communications equipment on top or within building structures.
FRP composites behave similarly to most materials in that they expand and contract due to changes in temperature. The coefficient of thermal expansion (CTE) varies with the content and type of resin and reinforcement used, as well as with the direction of the fiber. Typically, the CTE of glass-fiber-reinforced unsaturated polyester resin is 14–22 x 10–6 in/in/o F (25–40 x 10–6 mm/mm/o C). Most carbon fibers have a negative CTE and the result is a contraction in the fiber when temperature is increased. However, a properly designed carbon/epoxy laminate can be manufactured with a zero CTE.
Typically FRP composites are insulators. They are used for utility poles, stand-off insulators, and other applications where electrical conductivity is disadvantageous. An exception is carbon fiber, which alone is conductive. Although thermoset resins are non-conductive, fillers can be utilized to induce conductive or semi-conductive behavior if desired. Nonmagnetic FRP composite parts manufactured with glass fiber and traditional thermoset resins are non-magnetic. Magnetism can be engineered into FRP composite laminates through the incorporation of magnetically responsive fillers or fibers.
An extremely wide range of textures, shapes, and colours is achievable when manufacturing parts or building components with FRP materials. Various combinations of pigments, fine aggregates, and durable metallic powders can be added to the actual laminate in order to reduce or eliminate the need to paint the FRP composite products.
An FRP design begins by considering liquid polymer resins and formable reinforcing fibers. The finished component, or part, can be curved, corrugated, ribbed, or contoured into a variety of shapes. Unlike homogeneous materials, the design of an FRP laminate, component, or system can be tailored at the material level to increase the strength and stiffness of the finished product.