FIBER REINFORCED PLASTICS (FRP) Submitted by, Menon Lakshmi Suresh Divya C S Amrutha K S Lini cleetus C DEFINITION Fiber Reinforced Polymer (FRP) Composites are defined as: “A matrix of polymeric material that is reinforced by fibers or other reinforcing material” Processes • Matched die molding • RTM • Spray-up • Hand lay-up • Filament winding • Pultrusion • RIM Benefits Of FRP • HIGH STRENGTH/WEIGHT RATIO • ORIENTATED STRENGTH • DESIGN FLEXIBILITY • LIGHTWEIGHT • CORROSION RESISTANCE • LOW MAINTENANCE/LONG-TERM DURABILITY • LARGE PART SIZE POSSIBLE • TAILORED AESTHETIC APPEARANCE • DIMENSIONAL STABILITY • LOW THERMAL CONDUCTIVITY • LOW INSTALLED COSTS FRP COMPOSITE CONSTITUENTS • RESINS (POLYMERS) • REINFORCEMENTS • FILLERS • ADDITIVES MATERIALS: RESINS • PRIMARY FUNCTION: “TO TRANSFER STRESS BETWEEN REINFORCING FIBERS AND TO PROTECT THEM FROM MECHANICAL AND ENVIRONMENTAL DAMAGE” • TYPES: – THERMOSET – THERMOPLASTIC RESINS THERMOSET THERMOPLASTIC POLYESTER ACETAL VINYL ESTER ACRYRONITRILE BUTADIENE STYRENE (ABS) EPOXY NYLON PHENOLIC POLYETHYLENE (PE) POLYURETHANE POLYPROPYLENE (PP) POLYETHYLENE TEREPHTHALATE (PET) Matrix Materials – FRP • Intermediate length fiber reinforcement – The longer the fibers, the more difficult it is to coat the fibers enough to reap strength benefits – Low viscosity thermosets “wet-out” the materials better than high viscosity thermoplastics – Generally use unsaturated polyester and vinylester resins for FRP • Very long fibers or continuous fibers – Typically used with thermosets, also for “wet-out” reasons – Used generally in advanced composite parts and have greater material property requirements – Generally use epoxy resins Reinforcements • Three main types of fibers – Fiberglass – Carbon fiber or Graphite – Organic fibers, aramids (kevlar) • Hand lay-up technique is the simplest method of composite processing. • The processing steps are quite simple  First of all, mould is treated with a release agent-to prevent sticking  Gel coat layers are placed on the mold- to give decorative and protective surface  Put the reinforcement (woven rovings or chopped strand mat) [...]... polyurethane resin Reinforcement Glass fiber, carbon fiber, aramid fiber, natural plant fibers (sisal, banana, nettle, hemp, flax, coir, cotton, jute etc.) (all these fibers are in the form of chopped short fibers, flakes, particle fillers etc.) RESIN TRANSFER MOLDING (RTM [image courtesy:-www.engr.ku.edu] Type of material for which process is used Typical Preform Fiber Weaves Polyester resins Epoxy... ester, phenolic resin, unsaturated polyester, polyurethane resin Reinforcemen Glass fiber, carbon fiber, aramid fiber, t natural plant fibers (sisal, banana, nettle, hemp, flax etc.) (all these fibers are in the form of unidirectional mat, bidirectional (woven) mat, stitched into a fabric form, mat of randomly oriented fibers) Variation of hand lay-up Mould is treated with a release agent-to prevent... tooling) -continuous fiber over the entire part high fiber volume is obtainable -mandrel could be complex and expensive -inability to wind reverse curvature -ability to orient fibers in the load direction -fiber and resin used in lowest cost form -autoclave not necessary -a very fast and economic method -Lack of ductility -Low modulus of elasticity -inability to easily change fiber path within one... pulling resin-impregnated fibers through a heated die where curing occurs Characteristics -Pultrusion produces parts with -high fiber volume, high percentage of unidirectional reinforcement -primarily a method for thermosetting resins -one of few continuous FRP process -Accounts for 3% of total FRP -based on continuous fibers Pultrusion Process Steps: -String-up of desired fiber pattern -Resin impregnation... requirements Fiber Requirements -high tensile strength -highest mechanical quality -finishes to improve handling shaft 27 REINFORCEMENTS RESINS fiber in roving form E-glass, S-glass carbon/graphite aramid hybrids (within layer and layer to layer) wet or prepreg epoxy vinyl ester polyester Epoxy resins Polyester resins Phenolic resins Silicone resins Filament Windings Impregnation methods -Wet winding -Fiber. .. Impregnation methods -Wet winding -Fiber is impregnated immediately -Most common in aerospace -Most economical Prepreg winding - resin and fiber combined in separate step -better control -better wet-out -allows use of resin with viscosities too high for wet winding Wind fibers are n two ways: -planar winding: side by side no cross over -Helical winding: mandrel 29 Filament Windings Mandrel: can be in sections... control infusion rate and flow front of resin so that it infiltrates fiber preform evenly and completely, but quickly before gelling • resin is injected in center of part to guard against formation of air pockets and minimize distance resin must travel • care must be exercised to insure reinforcement does not move during injection (fiber wash) ADVANTAGES DISADVANTAGES - - Greater Tooling Design and... layers are placed on the mold- to give decorative and protective surface The gun sprays the mixture of chopped fiber, resin & catalyst on to a mould Rolled out to remove entrapped air & give a smooth surface Poor roll out can induce structural weakness by leaving air bubbles, dislocation of fibers and poor wet out • Spray lay-up method is used for lower load carrying parts like small boats, bath tubs,... dry reinforcement in a closed mold with wet thermosetting resin under pressure • production rate comparison – 2 - 8 pph (parts per hour) – spray-up ≅ 0.5 pph – SMC, injection molding ≅ 30 pph (chopped fibers, high pressures requires >>$ tooling) REINFORCEMENTS RESINS type Polyester E-glass, S-glass carbon/graphite aramid vinyl ester form mat fabric textile preform architecture (knitted, braided, 3-D . FIBER REINFORCED PLASTICS (FRP) Submitted by, Menon Lakshmi Suresh Divya C S Amrutha K S Lini cleetus C DEFINITION Fiber Reinforced Polymer (FRP) Composites are defined. Reinforcement Glass fiber, carbon fiber, aramid fiber, natural plant fibers (sisal, banana, nettle, hemp, flax, coir, cotton, jute etc.) (all these fibers are in the form of chopped short fibers, flakes,. polyurethane resin Reinforcemen t Glass fiber, carbon fiber, aramid fiber, natural plant fibers (sisal, banana, nettle, hemp, flax etc.) (all these fibers are in the form of unidirectional