钢筋混凝土圆杆中的应力波传播及层裂研究

Stress Wave Propagation and Spalling in a Steel Reinforced Concrete Cylindrical Bar

  • 摘要: 利用<i<Φ</i<74 mm的Hopkinson压杆对圆柱型钢筋混凝土试件进行了波传播实验和层裂实验研究,利用应变片记录杆中应力波信号,使用高速摄影机拍摄试件的拉伸破坏过程.实验结果表明:在较低的加载速率下,应力波在钢筋混凝土试件传播过程中呈现弹性波特性,不弥散不衰减;在较高的加载速率下,钢筋混凝土试件出现层裂现象,层裂强度在7 MPa左右;断裂试件中的裂纹在拉压应力波交替作用下反复张开闭合,随着应力波在杆中的衰减而趋于稳定.

     

    Abstract: By using the <i<φ</i<74 mm Hopkinson pressure bar, experiments were conducted to study stress wave propagations in a cylindrical steel reinforced concrete bar and the subsequent spalling of the bar. Strain gage were used to measure the stress wave propagations in the specimen, and a high-speed camera was used to record the spall fracture of the specimen. The experimental results show that under the lower loading speeds, elastic stress wave in the reinforced concrete specimen appears without observable dispersion and attenuation. At higher loading speeds, the reinforced concrete fractured due to reflected tensile stress pulse (spalling). The spall strength of the specimen is estimated to be about 7 MPa. In addition, the cracks on the concrete surface close and open repeatedly under the tension and compression of the reflected stress waves.

     

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