Abstract
Bending test and fracture toughness test of nine commercial composite resins were performed in water at 5〜55℃ to evaluate the effect of temperature when testing the mechanical properties of composite resins. Proportional limit, bending strength, and elastic modulus at bending test decreased with increases in testing temperature. However, plastic deformation during bending test increased with increases in testing temperature. The value of fracture toughness showed a high peak at 25〜37℃, then decreased at 55℃. In addition, the critical energy release rate increased significantly with the increase in temperature. These results indicated the testing temperature influenced fracture behavior of composites and the brittle manner of composites at a low temperature influenced fracture significantly more than elastic manner at high temperature.
