Calculation of adhesion strength at the interface of a coated particle embedded within matrix under multiaxial load

Analytical and finite element solutions of the stress fields around a particle under multiaxial thermomechanical load are derived as functions of the properties of the particle, the matrix and an interphase. The motivation for these calculations is to answer the question of how to load a sample containing a particle to measure the adhesion strength at the interfaces. The calculations provide the stress field and show that an interphase with a Youngʹs modulus lower than that of the matrix reduces stress concentration in the neighbourhood of the particle. The superposition of loads in different directions results in the creation of a more or less uniform distribution of tensile stresses (hydrostatic tension) around the particle, a stress situation that allows the determination of adhesion strength. The ratio of the applied stresses in different directions determines the extension of the area which is under high tensile loads. This provides the basis to develop a test technique for the examination of statistical effects which in addition to the bonding quality may influence adhesion strength at interfaces.