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The purpose of this research is determining experimentally the characteristics of tension and cyclic plastic behaviours of as‐received and annealed coppers and studying distribution of stress/strain field near the crack tip. Samples made by pure copper were annealed at 420°C for 40 minutes in electric furnace. To determine the properties of the cyclic plastic behaviour, proper tests with symmetric strain‐controlled conditions were performed on standard samples. Chaboche nonlinear hardening model was used to determine the cyclic plastic behaviour of both materials. According to results, annealing process creates isotropic hardening in the copper and also changes its initial kinematic hardening behaviour. Effects of the annealing and hardening on the variations of the stresses and strains around the crack tip were investigated. Also, ratcheting and mean stress relaxations versus number of cycles, inside the plastic region, were studied.

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The cure kinetics expression for Araldite LY-556 epoxy resin is determined by a differential scanning calorimeter (DSC). The heat of reaction, the rate of cure, and degree of cure are determined at constant temperature of 363, 373, 383, 393, 403, and 413 K (isothermal scanning) using the data generated by DSC. The ultimate heat of reaction also is measured at a constant heating rate of 5, 10, and 15 K/min (dynamic scanning). The viscosity is measured as a function of time at constant temperatures of 323, 343, and 363 K using a dynamic mechanical analyzer (DMA). Expressions are developed using the data generated by DSC and DMA, and by the curve fitting method, which represent the rate of cure, and the viscosity versus degree of cure and temperature. The new and accurate expressions are used for better modeling of the resin behavior.KEY WORDS: cure kinetics, degree of cure, rate of cure, heat of reaction, viscosity.

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