加热速率对中心直裂纹巴西圆盘试样断裂行为影响规律研究OA北大核心CSTPCD

This study investigates the fracture characteristics and damage mechanism of granite after treatment under different heating rates.The cracked straight-through Brazilian disc(CSTBD)specimen was used for high-temperature treatment with four heating rates under four sets of heating tempera-tures.The Brazilian splitting experiments were carried out using electro-hydraulic servo press after cool-ing down to room temperature,and the static fracture process was analyzed to investigate the effect of heating rate on the fracture mechanical properties of specimens.The results show that:(1)Granite trea-ted at different high temperatures shifted from brittle to ductile damage.(2)The peak damage load of granite treated with different heating rates at the same temperature decreased with the increase of heat-ing rate.At the same temperature,the increase of heating rate doesn't lead to obvious difference in the apparent color of granite,but with gradual increase of apparent cracks.(3)At different heating rates,the longitudinal wave velocity and elastic modulus at 200℃and 400℃show subtle changes,yet at 600℃and above,the longitudinal wave velocity and elastic modulus decrease significantly with the increase of heating rate.(4)The fracture toughness of granite shows gradual decay with the increase of tempera-ture.At the same temperature,type I fracture toughness of granite specimens decreases with the increase of heating rate.At 400℃,heating rate exerts maximum influence on the fracture toughness of granite.