Abstract Q345B steel circular tubes are widely applied in structural engineering applications, such as offshore platforms, bridges, and other structures, and they face potential risks of being subjected to the external loads of fires, explosions, or both during their service lives. In this study, the damage of Q345B steel circular tubes due to the combined action of fire and blast loading were analyzed. A specialized experimental platform was built, and experiments were performed on Q345B steel tubes with a range of wall thicknesses (a), fire loading durations (t), and stand-off distances (R) which means the distance between the bottom of the explosive and the upper surface of tube. The experimental local deflection, compressed degree, and local deformation volume are presented and studied in a quantitative manner. As the fire duration increased, the specimens underwent more noticeable deformation and damage. The local deflection amounts of the specimens treated with fire increased by 20%–50% compared to that of the specimen not exposed to fire at R = 17 cm. When R = 12 cm, the local deflection increased by 20%–120%. In addition, based on the stress–strain curves, the effects of the blue brittleness of the Q345B steel materials on the anti-blast performances of the specimens were examined. Finally, scanning electron microscopy was employed to explore the rupturing mechanism under a microscope.

中文翻译：

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钢圆管受火爆破坏的影响

摘要 Q345B圆管广泛应用于结构工程领域，如海洋平台、桥梁等结构物，在使用寿命期间面临着遭受火灾、爆炸或两者外加载荷的潜在风险。本研究分析了Q345B钢圆管在火爆载荷共同作用下的损伤。搭建了专门的实验平台，对Q345B钢管进行了一系列壁厚(a)、耐火载荷持续时间(t)和爆破距离(R)的实验。和管子的上表面。实验局部挠度、压缩程度和局部变形量以定量的方式呈现和研究。随着火灾持续时间的增加，试样发生了更明显的变形和损坏。在 R = 17 cm 处，与未暴露于火的样品相比，经火处理的样品的局部挠曲量增加了 20%–50%。当 R = 12 cm 时，局部偏转增加 20%–120%。此外，基于应力-应变曲线，研究了 Q345B 钢材料的蓝脆性对试样抗爆性能的影响。最后，采用扫描电子显微镜在显微镜下探索破裂机制。基于应力-应变曲线，研究了Q345B钢材料的蓝脆性对试样抗爆性能的影响。最后，采用扫描电子显微镜在显微镜下探索破裂机制。基于应力-应变曲线，研究了Q345B钢材料的蓝脆性对试样抗爆性能的影响。最后，采用扫描电子显微镜在显微镜下探索破裂机制。