This paper presents a comparative study about the numerical and experimental system identification and model updating‐based automated damage detection of concrete‐encased composite column‐beam connections. Four different column‐beam connection types named as CBC#A, CBC#B, CBC#C, and CBC#D were considered without any changes in geometrical configuration. Numerical and experimental dynamic characteristics were extracted by initial finite element analysis and nondestructive experimental measurements for undamaged condition. Enhanced frequency domain decomposition (EFDD) method was used for experimental modal extractions. A good agreement was observed between experimental natural frequencies but not enough correlation between damping ratios for all connection types. Maximum differences between initial finite element and undamaged experimental results were calculated as 34.68% for CBC#A, 40.78% for CBC#B, 33.15% for CBC#C, and 47.13% for CBC#D type connection details. The differences were reduced to 0.24%, 0.24%, 0.16%, and 0.15%, respectively, by automated model updating procedure using spring coefficient, modulus of elasticity and weight per unit volume. In the case of the damaged condition, lateral forces were applied to simulate the effect of an earthquake. Cracks strongly affected the natural frequencies. The mode shapes were not broken evidently after damaged conditions. The mode shapes definitely deviated a bit, but generally the same after damages. The natural frequencies have decreased non‐monotonically due to the decrease in the rigidity of the column and beam at the cracked section. Maximum differences were calculated as 14.96% for CBC#A, 41.08% for CBC#B, 31.35% for CBC#C, and 45.93% for CBC#D type connection details. After automated model updating the above‐mentioned differences were reduced to 0.35%, 0.78%, 0.73%, and 0.85% respectively. Contour diagrams of changes of updating parameters were plotted for damage identification. The regions with high difference rates indicated the location of the damage.

中文翻译：

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基于模型更新的混凝土包裹组合柱梁连接的自动损伤检测

本文提供了一个关于数值模拟和实验系统识别以及基于模型更新的混凝土包装复合柱-梁连接的自动损伤检测的比较研究。考虑了四种不同的柱梁连接类型，分别为CBC＃A，CBC＃B，CBC＃C和CBC＃D，但几何结构没有任何变化。通过初始有限元分析和无损实验测量，提取了数值和实验动态特性。增强频域分解（EFDD）方法用于实验模态提取。在实验固有频率之间观察到很好的一致性，但是对于所有连接类型，阻尼比之间的相关性不足。初始有限元与未损坏实验结果之间的最大差异计算为CBC＃A为34.68％，CBC＃B为40.78％，CBC＃C为33.15％和CBC＃D类型连接细节为47.13％。通过使用弹簧系数，弹性模量和每单位体积重量的自动模型更新程序，差异分别减小到0.24％，0.24％，0.16％和0.15％。在受损情况下，施加横向力来模拟地震的影响。裂缝强烈影响了固有频率。损坏条件后，模态形状没有明显破坏。振型肯定有偏差，但损坏后通常相同。由于裂缝处柱和梁的刚度降低，固有频率非单调降低。对于CBC＃A，最大差异计算为14.96％，对于CBC＃B，为41.08％，对于CBC＃C，为31.35％，对于CBC＃D类型连接详细信息为45.93％。在自动模型更新后，上述差异分别降低到0.35％，0.78％，0.73％和0.85％。绘制了更新参数变化的等高线图，以进行损伤识别。差异率高的区域指示损坏的位置。