Biaxial testing of continuous fibre reinforced aluminium tubes

摘要

Composite tubes of aluminium and aluminiumalloy containing hoop wound alumina (Altex) fibres werefabricated using a liquid metal infiltration method. The tubeswere well consolidated, with low porosity, and good bondingbetween fibre and matrix, as confirmed using 'rule of mixtures'calculations of elastic modulus. Mechanical properties wereevaluated in the principal directions of the tube under uniaxialand biaxial stress loading conditions, and damage modes werestudied. Stress quarter diagrams were constructed on the basis ofa maximum stress failure mechanism, and failure envelopeswere produced using the measured values of yield stress andfailure strength. The composition and condition of the matrixwas shown to influence the shape of the failure envelope and inturn, the mode of failure of the tube for a given biaxial stressratio. Good correlation was obtained between predictions madefrom the stress quarter diagrams and the fracture paths observedin tested tubes.