Dynamic Tensile Behavior of Steel HRB500E Reinforcing Bar at Low, Medium, and High Strain Rates
Dynamic Tensile Behavior of Steel HRB500E Reinforcing Bar at Low, Medium, and High Strain Rates
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HRB500E 钢钢筋在低、中、高应变率下的动态拉伸行为
DOI：
10.3390/ma13010185
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发表时间：
2020-01-01
期刊：
影响因子：
3.4
通讯作者：
Elchalakani, Mohamed
中科院分区：
文献类型：
--
作者：
Zeng, Xiang;Huo, Jingsi;Elchalakani, Mohamed
在评价钢筋混凝土结构在爆炸、冲击等极端动荷载作用下的性能时，需要考虑工程材料的应变率效应。然而，500 MPa级抗震热轧高强带肋钢筋（HRB 500 E），用于关键的钢筋混凝土构件，以提高抗震性能的应变率性能，还没有调查和公开的文献报道。这就限制了它在极端动荷载作用下钢筋混凝土结构的应用。采用机电式万能试验机和伺服液压式高速试验机对HRB 500 E钢进行了动态拉伸试验。获得了应变速率为0.00025 ~ 550 s-1时的应力-应变曲线，发现HRB 500 E钢对应变速率非常敏感。针对现有屈服应力动态增加系数（DIFy）计算公式不适用于HRB 500 E钢的问题，根据试验结果对常用的Cowper-Symonds和Malvar模型进行了修正。此外，还标定了描述工程应力-应变关系的Mander材料模型参数。最后，约翰逊-库克和建议的本构模型的真实应力-应变关系进行了检查。与Johnson-Cook模型相比，该模型对屈服应力的预测精度更高。
The strain rate effect of engineering materials should be considered in the assessment of the performance of reinforced concrete (RC) structures under extreme dynamic loads such as blast and impact. However, the strain rate behavior of 500 MPa-grade anti-earthquake hot-rolled high-strength ribbed bar (HRB500E), used in critical RC members to improve the anti-earthquake performance, has not been investigated and reported in the open literature. That restricts its application in RC structures subjected to extreme dynamic loads. In this paper, dynamic tensile tests of HRB500E steel were conducted using an electromechanical universal testing machine and a servo-hydraulic high-speed testing machine. The stress–strain curves at strain rates ranging from 0.00025 to 550 s−1 were obtained where HRB500E steel was found significantly sensitive to strain rate. Existing formulations to evaluate the dynamic increase factor for yield stress (DIFy) are found to be not suitable for HRB500E steel, thus the widely used Cowper–Symonds and Malvar models for predicting the DIFy were modified based on the test results. Furthermore, the parameter of the Mander material model for describing engineering stress–strain relationship was also calibrated. Finally, the Johnson-Cook and proposed constitutive models for the true stress–strain relationship were examined. The proposed constitutive model can provide better prediction accuracy for yield stress than the Johnson-Cook model.