Pultruded materials

The main characteristics of a composite material are the breaking strength, the elasticity modulus, and the ultimate strain. Specifically with pultruded materials (bars and laminates), the volume firaction is an important piece of information to have that is, the volume of fibers on the total volume of product, whereas when dealing with fabrics, the values reported above are considered for dry fabrics. 

Tables 10 and 11 show pultruded materials with glass fiber and carbon fiber respectively. For both tables the following abbreviations have been used PP-polypropylene, PMMA-poly (methyl methacrylate), PU-polyurediane, NY6-nylon 6, PPS-polyphenylene sulfide, UP-unsaturated polyester, PH-phenolic resin and ABS-acrylobutadiene styrene.

As pointed out in the beginning of the chapter—and perhaps also noticeable from the process description earlier—the pultrusion process at first appears rather simple and straightforward however, several intricacies arise on closer inspection. The key technology issues of pultrusion of thermoset-matrix composites are usually considered to be resin formulation, temperature control, material guidance, and die design (not in order of importance). It is typically the skill in these areas that distinguishes a successful pultruder from his hapless competitor. 

You are to pultrude a thin fiber reinforced epoxy plate at arate of lcm/s. Assume kinetic properties given in the last two problems and that the material is best represented with the autocatalytic second order reaction kinetic model of the previous problem. You are asked to design the die and the process to manufacture this product. 

Plastics find extensive use in several areas of fiber optic cables. Buffer tubes, usually extruded from high-performance plastics such as fluoropolymers, nylon, acetal resins, or polybutylene terephthalate (PBT) are used for sheathing optical fibers. A blend o PVC and ethylene vinyl acetate (EVA) polymer, such as Pantalast 1162 of Pantasote Incorporated, does not require a plasticizer, which helps the material maintain stability when in contact with water-proofing materials. PVC and elastomer blends, Carloy 6190 and 6178, of Cary Chemicals are also used for fiber optic applications (Stiffening rods for fiber optics are either pultruded epoxy and glass or steel. Around these is the outer jacketing, which is similar to conventional cable.)... 

Different TP pultrusion processes are used. As an example Thermoplastic Pultrusion Technologies (TPT), Yorktown, VA, USA, uses a hot-melt injection process for pultruding RP thermoplastic. Unlike TS pultruded profiles, TP profiles can be postformed and reshaped. Higher continuous use temperatures are possible with some TP matrices, and line speeds are faster with raw materials usually costing less. 

All materials were pultruded using an open resin impregnation bath (Chapter 5). During pultrusion both pull force and die temperature were monitored at all times and allowed to reach steady state before any material was considered usable. 

Machine or lengthwise Refers to product output in the machine direction 90° to the transverse direction. Materials such as sheet being extruded or RP being pultruded, basically are exiting in the machine inline direction where the direction follows the flow of the plastic firom the die. At 90° to this direction is the transverse or crosswise direction. 

Pakalapati et al [115] investigated some carbon/thermoplastic laminates. The materials were pultruded and they consisted of 50 v/o unidirectional continuous polyacrylonitrile-based carbon fibres in DuPont J-2 aromatic polyamide-based thermoplastic matrix. They were subjected to anodic and cathodic currents in sea water. Dynamic mechanical analysis was carried out in situ to measure the shear storage modulus (G ) and shear loss modulus (G") of 1.27mm diameter rod shaped samples, subjected to small amplitude torsional oscillations. The moduli were constant with time in air. 

Standard test method for mode I interlaminar fracture toughness of unidirectional fiber-reinforced polymer matrix composites Standard test method for translaminar fracture toughness of laminated and pultruded polymer matrix composite materials... 

Standard test method for translaminar fracture toughness of laminated and pultruded polymer matrix composite materials... 

Design basics for the use of FRP profiles in civil engineering applications are provided in ASCE (1984) and EUROCOMP (1996), but these two documents do not have model code-like status. Additionally, there exist design manuals published by the manufacturers of pultruded FRP profiles, e.g. FiberlineComposites (2003). Beside the design concept, all the necessary material parameters and associated material safety factors are given in these manuals. 

The conceptual design of the bridge resulted from three main constraints at that time (i) the low clearance above water that required a load-carrying structure above the walkway, (ii) the annual cycles of installation/removal, and (iii) the available pultruded GFRP shapes provided by the manufacturer (Fiberline Composites, Denmark). The choice of GFRP materials was based mainly on their low selfweight for the installation and removal cycles, and the expected low to zero maintenance [14]. 

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