Abstract Dynamic tensile tests of concrete materials at high strain rates are primarily splitting experiments and spalling experiments at present, however, certain limitations exist in these methods to indirectly study dynamic tensile mechanical behaviour of concrete materials. Thus it is necessary to perform direct dynamic tensile study of concrete materials with a large-diameter split Hopkinson tensile bar (SHTB). Concrete is considered as a two-phase composite material which composed of coarse aggregates and cement matrix in this paper, then cylindrical and dumbbell-shaped three-dimensional mesoscale concrete models are established and applied to SHTB simulation research. Three contact modes between concrete specimen and member bars are discussed based on existing experiments and our numerical simulation analysis. The results show that established finite element models can effectively simulate SHTB tests and mesoscale concrete models also reflect proper tensile behaviour at high strain rates, which also provides convenience to mesoscopic numerical simulation research of many other heterogeneous materials. At last, a proper contact mode is chosen to perform mesomechanics analysis of concrete materials subjected to four types of tensile impact wave, then five mesoscale concrete models with different aggregates content are established and corresponding numerical simulation analysis are conducted.

中文翻译：

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基于中尺度模型的混凝土材料直接动态拉伸研究

摘要 目前，高应变率下混凝土材料的动态拉伸试验主要是劈裂试验和剥落试验，但这些方法在间接研究混凝土材料的动态拉伸力学行为方面存在一定的局限性。因此，有必要使用大直径分裂霍普金森拉伸杆 (SHTB) 对混凝土材料进行直接动态拉伸研究。本文将混凝土视为由粗骨料和水泥基体组成的两相复合材料，建立了圆柱形和哑铃形的三维中尺度混凝土模型，并将其应用于SHTB模拟研究。基于现有的实验和我们的数值模拟分析，讨论了混凝土试件和杆件之间的三种接触模式。结果表明，建立的有限元模型可以有效地模拟SHTB试验，中尺度混凝土模型也反映了高应变率下的适当拉伸行为，这也为许多其他非均质材料的细观数值模拟研究提供了便利。最后选择合适的接触方式对混凝土材料在四种拉伸冲击波作用下进行细观力学分析，建立五种不同骨料含量的细观混凝土模型，并进行相应的数值模拟分析。