基于ABAQUS型钢混凝土梁温度场分析

Temperature Field Analysis of Steel-Reinforced Concrete Beams Using ABAQUS

摘要: 火灾作用下构件内部温度场随时间和空间的变化规律对结构和构件抗火性能具有重要意义。本文通过ABAQUS有限元软件来建立型钢混凝土梁的传热模型，研究工字钢、保护层厚度、升温条件、受火方式这几种影响因素对截面温度场的影响。结果表明：尽管钢材自身温度变化幅度较小，但工字钢对构件截面温度场的分布具有显著影响，其影响程度随受火时间呈先增后减的趋势，并于72 min时达到最大值；此外，混凝土保护层有效发挥了隔热保护作用，随着其厚度的增加，钢筋的耐火时间显著延长。对比混凝土保护层厚度分别为30 mm、40 mm的升温曲线发现：当混凝土保护层增加10 mm后，相同受火试件的钢筋降低100℃以上；在不同升温曲线下，混凝土和钢筋的温度变化趋势同其对应的四种升温曲线温度变化趋势基本上是一致的，HCM升温条件下钢筋和混凝土结点温度最高，依次是HC、ISO-834、ASTM；在单面、两面、三面受火方式下，单面受火温度整体低于三面受火。随着受火面数的增加，截面温度也随之增加。通过分析混凝土温度场云图发现：除两面外，单面和三面受火方式下温度分布都是单轴对称。

Abstract: The temporal and spatial variations of internal temperature fields within structural members under fire exposure are crucial for evaluating the fire resistance performance of structures and components. This study employs ABAQUS FEA Software to establish a model of heat transfer for steel reinforced concrete beams, investigating the influence of several factors—including I beam, concrete cover thickness, heating conditions, and fire exposure scenario—on the temperature distribution within the cross-section temperature field. Although the temperature change of the steel itself is relatively limited, the I-beam significantly influences the temperature distribution across the component cross-section. The extent of this influence initially increases and then decreases with prolonged fire exposure, reaching its maximum value at 72 minutes. The concrete cover effectively fulfills its insulating function, and as its thickness increases, the fire resistance time of the steel reinforcement is significantly extended. A comparison of the heating curves for concrete cover thicknesses of 30 mm and 40 mm reveals that an increase of 10 mm in cover thickness results in a temperature reduction of over 100˚C in the reinforcing steel at the same duration of fire exposure. Under different heating curves, the temperature change trends of concrete and reinforcing steel generally align with their corresponding four heating curve temperature profiles. Under HCM heating conditions, the highest temperatures occur at the concrete-reinforcing steel joints, followed by HC, ISO-834, and ASTM conditions. Under single-sided, double-sided, and triple-sided fire exposure conditions, the overall temperature of single-sided exposure is lower than that of triple-sided exposure. As the number of exposed surfaces increases, the cross-sectional temperature rises accordingly. Analysis of the concrete temperature field nephograms reveals that, with the exception of two-face exposure, the temperature distribution under both one-face and three-face fire scenarios exhibits a mono-axial symmetric pattern.