Long fibre thermoplastic composites

Thus, in the automotive industry, long fibre thermoplastic (LFT) composites are used to produce underbody panels, instrament panel carriers, front end modules, battery trays, sunroof beams, mirror brackets, fuel rails, door modules, seat stmc-tures, convertible header bows, door plate carriers, roof and trunk lids, exterior claddings, skid plates, running boards, step assists, front-end carriers, bumper beams, lift gates, spare wheel tubs and other stmctiual parts (Vaidya, 2011). 

Hawley, R. and Jones, R. (2005), In-line compounding of long-fibre thermoplastics for injection molding , Journal of Thermoplastic Composite Materials, 18, 459 64. DOI 10.1177/0892705705054413. 

Thermoplastic composites, GMT. According to The European Alliance for SMC, the production of glass mat reinforced thermoplastics (GMT) and long fibre reinforced thermoplastics (LET) was up about 9% in 2002, demonstrating bright future prospects. Some examples are ... 

Processing of LFRT or LFT - long fibre (reinforced) thermoplastics injection, composite insert moulding, compression moulding, extrusion-compression. 

HTPC (Hybrid ThermoPlastic Composite) bumper beams made by Plastic Omnium are used by General Motors on the Pontiac Montana, Chevrolet Venture and Oldsmobile Silhouette. Continuous woven fibres are overmoulded with a long or short fibre reinforced polypropylene to save weight (6 kg), enhance impact resistance (20-40%) and integrate numerous functions such as reinforcement ribs. The process is fully automated. 

A solid structural substance produced by a combination of two or more materials that retain their identities. Typically, one of the materials combined is the strengthening agent, the other being the matrix (a thermoset or a thermoplastic resin). The word composite is also used for systems that are reinforced (reinforced where cumulative properties are superior to the individual components) by addition of certain solid particles (i.e., short fibre composites - long fibre composites - continuous fibre composites). 

Two alternative modes of fracture have been defined, both involving shear on the crack plane. In mode II, shear is parallel to rhe crack propagation direction. In mode III, shear is normal to the propagation direction. These types of fracture are important in long-fibre composites and in adhesives, because of anisotropy. They are of minor importance in thermoplastics. Cracks in isotropic materials tend to turn in a direction normal to the tensile stress, giving mode I fracture, whatever the initial orientation of the crack plane. 

Polymers vary widely in their processing characteristics, and it is important to ensure that the design developed can be produced economically and efficient from the chosen material. The most obvious differences in processing behaviour are between thermoplastics and long-fibre composites, but fiiere are also significant variations within each class of materials. To take an extreme example, PTFE has such a high melt viscosity that it cannot be injection-moulded, but has to be formed from powder by... 

Mieck, K. P., Reussmann, T., and Hauspurg, C. (2000). Correlations for the fracture work and falling weight impact properties of thermoplastic natural/long fibre composites. Materialwissen-schcift und Werkstoffteclmik 31, 169-174. 

The data bands for short length fibre thermoplastics and long fibre reinforced thermosets lie adjacent to one another with a similar shape if the fatigue data for each composite is divided by the ultimate strength (Table 10.3). 

Schemme et al.. Long Fibre Reinforced Thermoplastics for Automotive Applications- The European Alliance for Thermoplastic Composites (EATC), Wurzburg (2001). 

Obtaining electrical conductivity. Short fibres are added to thermoplastics to obtain EMI, ESD or conductive grades. In certain composites, long or continuous fibres partially replace glass fibres. 

Compounds are short (/w 0.3 mm) or long (> 0.6 mm) fibre reinforced thermoplastic or thermoset polymeric materials, which are processed automatically (injection or compression moulding), have good (mechanical) properties (for automotive, electric and electronic applications) and are relatively cheap. Composites contain continuous fibres (rovings, fabrics or mats), usually combined with thermosets, have excellent mechanical (structural) properties, but are very expensive because lack of an industrial process (mainly used in aerospace and aircraft industry). 

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