以四點彎曲試驗量測不同溫度作用下砂岩複合型斷裂韌度之研究

This study proposes a single edge-cracked bending specimen under four-point bending configuration to measure the mixed-mode fracture toughness of rocks. The testing materials are sandstones. This study arranges the experimental setups of four-point bending tests for measurements of modes I + II fracture toughness. There are five different loading conditions for the mode I + II fracture toughness. These loading conditions are one mode I, three different modes I + II and one mode II. This study considers three thermal conditions: 25°C, 300°C, and 600°C. Mixed Modes fracture toughness for I + II are calculated. One observes that the mode I + II fracture toughnesses in 25°C condition are much higher than those in 300°C and 600°C conditions. Therefore, this study effectively utilizes a simple four-pointbending test to measure the mixed-mode fracture toughness of sandstones.