Rocks are generally deformed and fractured upon various scales of strain rates. Understanding the strain rate effects on the thermal infrared radiation (IR) characteristics of rock materials is crucial for predicting and detecting rock failure. In the study, uniaxial compression experiments were conducted on sandstone samples at different strain rates using an Instron hydraulic servo testing machine and a split Hopkinson pressure bar (SHPB) system. Meanwhile, a thermal infrared camera was utilized to capture and record the changes in the IR temperature on the rock surface. The spatial and temporal evolution of thermograms, IR temperature distribution histograms, and average IR temperature () during testing were obtained and analyzed. A quantitative correlation between strain rate and the variation in () was established. Furthermore, the dissipation of heat energy () in the sandstone samples during SHPB tests was estimated. Results indicated that at relatively lower strain rates (ranging from 10 to 10 s), the of rock sample exhibited slight dependence on strain rate. However, a significant rate sensitivity emerged when the strain rate exceeded a specific threshold (approximately 137.09 s for the tested sandstone). The rate-dependent behavior of across the investigated range of strain rate (up to 10) can be characterized by an allometric power model. Notably, during SHPB testing, the proportion of was negligible despite the pronounced rate dependency of heat energy. The abrupt rises in and under dynamic loading conditions can be elucidated by the increasing occurrence of shear cracks and energy-level jumps stimulated by impact disturbance.

中文翻译：

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动态载荷下砂岩热红外辐射的应变率依赖性：实验室测试的见解


岩石通常会在不同程度的应变率下变形和破裂。了解应变率对岩石材料热红外辐射 (IR) 特性的影响对于预测和检测岩石破坏至关重要。在这项研究中，使用 Instron 液压伺服试验机和分体式霍普金森压力杆 (SHPB) 系统对不同应变率的砂岩样品进行了单轴压缩实验。同时，利用热红外相机捕捉并记录岩石表面红外温度的变化。获得并分析了测试过程中热谱图、红外温度分布直方图和平均红外温度 () 的空间和时间演变。建立了应变率与 () 变化之间的定量相关性。此外，还估计了 SHPB 测试期间砂岩样品中的热能耗散 ()。结果表明，在相对较低的应变速率（范围为 10 至 10 s）下，岩石样品的应变速率表现出轻微的依赖性。然而，当应变率超过特定阈值（测试砂岩约为 137.09 s）时，就会出现显着的速率敏感性。在所研究的应变率范围（最多 10）内，速率相关行为可以通过异速生长功率模型来表征。值得注意的是，在 SHPB 测试期间，尽管热能具有明显的速率依赖性，但所占的比例可以忽略不计。动态载荷条件下的突然上升可以通过剪切裂纹的增加和冲击扰动刺激的能量水平跳跃来解释。