| Abstract: | Reinforced thermoplastics are composites consisting of a viscoelastic plastics matrix of low strength and a material (mostly inorganic) which has a high strength and a high modulus of elasticity, showing purely elastic strain. Globular and fibrous particles can be used for reinforcing. In the first case, the reinforcing action is largely due to an isotropic reduction of the strainability of the thermoplastic. In the second, more important case, the fibres can also accumulate stress from the matrix. In both cases, the elastic and viscous components of strain are pushed closer together. In practice, irregularities in the orientation of the fibres and continually changing patterns of stress cannot be avoided. These give rise to difficulties in checking the theoretical treatment of thermoplastics reinforced with short fibres. The basic element itself, i.e., the individual fibre embedded in the matrix has several variants, i.e., the length of the fibre, the ratio of the fibre length to the diameter, the critical fibre length determined from the interfacial shear strength and fibre strength, and the tensile strength in the transverse direction. |
