Chen Xiaocui, Sun Liguo, Zhao Wenhu, Zheng Yuan
College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, China.
College of Mechanics and Materials, Hohai University, Nanjing 211100, China.
Sensors (Basel). 2020 Oct 22;20(21):5994. doi: 10.3390/s20215994.
Three-point bending experiments of concrete beams were conducted under the strain rate range of 10 s and 1.5 × 10 s. A novel 3D laser scanner, Handy SCAN, was employed to detect the areas of interface, mortar and aggregate on the crack surface after the experiment. In this paper, the inhomogeneity of materials and the inertial effect were considered as the main factors in the strength enhancement of concrete together with a proposed dynamic model. With the obtained experimental results, the initial elastic modulus and tensile strength of concrete showed obvious rate sensitivity. Moreover, an empirical relationship of dynamic increase factor and strain rate was established for the strain rate range of 10 s and 1.5 × 10 s. The contributions of aggregate and inertia effect to the dynamic enhancement of concrete strength were quantified with respect to the loading rate. The rate effect of concrete obtained by the experiments was verified by the finite element analysis on the mesoscopic scale with the model built by the three-dimensional random aggregate software.
在10⁻⁵ s⁻¹至1.5×10⁻⁴ s⁻¹的应变率范围内对混凝土梁进行了三点弯曲试验。试验后，采用一种新型的三维激光扫描仪Handy SCAN来检测裂缝表面的界面、砂浆和骨料区域。本文将材料的不均匀性和惯性效应视为混凝土强度增强的主要因素，并提出了一个动态模型。根据获得的试验结果，混凝土的初始弹性模量和抗拉强度表现出明显的率敏感性。此外，针对10⁻⁵ s⁻¹至1.5×10⁻⁴ s⁻¹的应变率范围建立了动态增强因子与应变率的经验关系。相对于加载速率，量化了骨料和惯性效应对混凝土强度动态增强的贡献。通过三维随机骨料软件建立的模型，在细观尺度上进行有限元分析，验证了试验得到的混凝土速率效应。
