An unacceptable low value of the manoeuvre stability

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Glass fibre 1. Easily converted into high resistance fibres. 2. Easily available and economically achievable. Compatible with most manufacturing processes. 3. Relatively strong fibres, but stiffness not very high. 4. Chemically inert, when combined with many plastics. 5. Good adhesion with most resins. 6. Small thermal expansion. The basic constituent of glass fibre is silicon, combined With other elements. To avoid surface defects due to the abrasion during the Wire drawing process, a sizing coating is used. Carbon fibre 1. Very high elastic modulus. 2. High strength (HS) or high modulus (HM) fibres. 3. High compression and fatigue strength. 4. High temperature resistant in non-oxidant atmosphere. 5. Chemically resistant at room temperature. 6. Thermal expansion is zero, even negative in the fibre’s longitudinal direction. 7. Good electrical and thermal conductivity. 8. Good resistant to humidity // Disadvantages • Expensive • Low toughness and bad abrasion-resistant. • It does not support neither oxidant acids at high temperatures, nor metals that can form carbides. Organic fibres -Difficult manufacturing Aramid or Aromatic Polyamide: 1. High specific tensile strength. 2. Zero or negative thermal expansion in longitudinal direction. 3. Very good absorption of vibrations. 4. Very good impact resistant, as well as penetration, abrasion and fatigue resistant. 5. Good chemical resistant except to very hard acid or bases. //Drawbacks debil at compression (so in bending), hygroscopic (absorb water) and adhesion with resins not good.  Must be cut with specific cutters or scissors. Fibres comparison Glass Fibre: Cheap, specially mat. Lightweight, toughness, stiffness and strength. Improvements in stiffness And strength when cloth glass fibre is used. Aramid Fibres: High strength, toughness and low density, BUT expensive. Low compressive strength, UV Degradation and difficult to get cut. Carbon Fibres: High tensile and compressive strength, stiffness, low density, good fatigue response BUT Very expensive. Fragile when subjected to impact and aesthetically attractive. Lightweight applications in Which, stiffness and strength are crucial. 


Matrix phase · Connects fibres and transmits forces. · Protects fibres from abrasion, chemical reactions. · Separates fibres and avoids crack propagation (ductility, plasticity) Strength depends on the fibre-matrix interface. Organic matrix: - Thermoplastics (polypropylene, polycarbonate, polystyrene) • properties depend on monomers, not on curing • soften and flow as temperature raises • high viscosity: infiltration problems (matrix does not reach all fibres) • high contraction when solidification • Higher toughness and cheaper than resins (thermosets) - Thermoset resins (epoxy, polyester, fenolic) • Most used; low viscosity so good, impregnation; different fibre lengths admitted • Properties depend on the initial molecule and intermolecular bonds (% curing) • They do not soften with temperature • Curing: room temperature or higher. • Post-curing: necessary for optimal properties • Fragile • Volatile products are released during processing • Better properties than thermoplastics 1. Epoxy:  Good long term stability, • High strength// More expensive than polyester • Longer curing time 2. Polyester:  Fast curing, • Cheap • Easy to use //  Worse mechanical properties • Worse long term stability

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