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چکیده
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Copper/Titanium Dioxide (CuTiO2)samples were fabricated at three temperatures(450 °C, 650 °C, 850 °C) using: a universal testing machine (quasi-statically at the strain rate of 8 × 10–3 s −1 ), a drop Hammer(dynamically at the strain rate of about 8 × 102 s −1 ), and a modified Split Hopkinson Pressure Bar(strain rate of about 1.6 × 103 s −1 ). The effects of reinforcing particle size on relative density and damage parameter of Cu reinforced by 0, 2.5, 5 and 10% volume fractions of nano- and micro-sized TiO2were investigated. The results indicated that the size of TiO2 particles, loading rate, and temperature had significant effect on relative density and damage parameter. The results also showed that the Quasi-Static method was superior to the other two methods. In addition, by increasing temperature, the mechanical properties of the composites were improved. The results showed that the effect of nano sized reinforcement particles on damage parameter was more profound than micro sized reinforcement particles. In this work, a new damage model considering the effects of strain rate, temperature, volume fraction and the aspect ratio of particles on damage parameter was proposed. The damage parameter was obtained using relative density and elasticity modulus. The results showed significant difference between the two methods. However, the density method yields more accurate and realistic results
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