Steel-fiber-reinforced composite bar (SFCB) is a composite bar composed of a crescent-rib steel bar and an outer protruded fiber-reinforced polymer (FRP) layer. Due to its unique post-yield stiffness and superior anti-corrosion behavior, the SFCB is except to be an ideal reinforcement for concrete structures subject to a high corrosion environment. For SFCB-reinforced concrete cylinders, their internal damage mechanism has never been experimentally studied but was usually speculated with the brittle failure due to the potential brittle fracture of the SFCB. To reveal the compression damage mechanism of SFCB-reinforced concrete cylinders, a uniaxial compression test for SFCB-reinforced concrete cylinders was carried out at first. The entire damage process of SFCB-reinforced concrete cylinders was monitored in real-time by acoustic emission (AE), a widely used nondestructive testing method. The test result shows that the SFCB-reinforced concrete cylinders fail after the buckling of longitudinal SFCB or the fracture of the stirrup. The intensity signal analysis of AE proves the failure mode of the SFCB-reinforced concrete cylinder was close to a plastic failure instead of a brittle failure. Furthermore, a new damage visualization method is proposed to analyze the internal damage of the concrete cylinders by using the spatial b value of AE. The T value was constructed by combining the spatial b value with the density distribution of AE events. It is proven that the T value is highly sensitive to the serious damages of the concrete cylinders and can be used to identify the damage locations inside the concrete cylinders.

中文翻译：

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基于声发射的钢纤维复合钢筋混凝土圆柱体损伤视觉识别

钢纤维增强复合钢筋（SFCB）是由新月形肋钢筋和外部突出的纤维增强聚合物（FRP）层组成的复合钢筋。由于其独特的屈服后刚度和出色的抗腐蚀行为，SFCB 是高腐蚀环境下混凝土结构的理想增强材料。对于 SFCB 钢筋混凝土圆柱体，其内部损伤机制从未进行过实验研究，但通常推测是由于 SFCB 潜在的脆性断裂而导致的脆性破坏。为揭示SFCB钢筋混凝土圆柱体的压缩损伤机理，首先对SFCB钢筋混凝土圆柱体进行了单轴压缩试验。通过声发射 (AE) 实时监测 SFCB 钢筋混凝土圆筒的整个损坏过程，一种广泛使用的无损检测方法。试验结果表明，SFCB钢筋混凝土圆柱体在纵向SFCB屈曲或箍筋断裂后失效。AE强度信号分析证明SFCB钢筋混凝土圆柱体的破坏模式接近塑性破坏而不是脆性破坏。此外，提出了一种新的损伤可视化方法来分析混凝土圆柱体的内部损伤。b AE 值。该Ť值通过空间组合构造b值与AE事件的密度分布。实践证明，T值对混凝土圆柱体的严重损伤高度敏感，可用于识别混凝土圆柱体内的损伤位置。