两种不同加载方法下的混凝土剪切断裂过程对比研究
发布时间：2018-11-10 19:21
【摘要】：采用室内试验和数值模拟相结合的方法分析半边对称加载法和四点剪切加载法的联系与区别。首先对不同参数的半边对称加载试件和四点剪切梁分别进行断裂过程试验,以研究其裂缝扩展形态和断裂韧度;然后通过扩展有限元方法对裂缝尖端应力情况进行分析。结果表明:半边对称加载试件裂缝尖端剪切应力比垂直于预制缝的张拉应力大得多,裂缝沿着原预制缝方向扩展,断裂韧度与初始缝长无关,但随着试件长度的增加和高度的减小而增大;四点剪切梁试件裂缝尖端存在大小相当的剪切应力和最大主应力,裂缝起于预制缝尖端,扩展到近加载点位置附近,断裂韧度与试件的几何尺寸无关,随着初始缝长的增大和近加载点与预制缝截面距离减小而增大。
[Abstract]:The relationship and difference between the semi-symmetric loading method and the four-point shear loading method are analyzed by means of laboratory test and numerical simulation. In order to study the crack propagation morphology and fracture toughness, the crack tip stress was analyzed by means of the extended finite element method (EFEM), and the fracture process tests were carried out on the semi-symmetric loaded specimens and four-point shear beams with different parameters respectively in order to study the crack propagation morphology and fracture toughness. The results show that the shear stress at the crack tip is much greater than the tensile stress at the crack tip perpendicular to the prefabricated joint, the crack propagates along the original prefabricated joint, and the fracture toughness is independent of the initial fracture length. But it increases with the increase of the length and the decrease of the height. The crack tip of the four-point shear beam has the same size of shear stress and maximum principal stress. The crack starts at the tip of the prefabricated joint and extends near the loading point. The fracture toughness is independent of the geometric size of the specimen. With the increase of the initial joint length and the decrease of the distance between the near loading point and the prefabricated joint section, it increases.
【作者单位】： 南京水利科学研究院;
【基金】：国家自然科学基金(51325904,1279111)
【分类号】：TU528
[Abstract]:The relationship and difference between the semi-symmetric loading method and the four-point shear loading method are analyzed by means of laboratory test and numerical simulation. In order to study the crack propagation morphology and fracture toughness, the crack tip stress was analyzed by means of the extended finite element method (EFEM), and the fracture process tests were carried out on the semi-symmetric loaded specimens and four-point shear beams with different parameters respectively in order to study the crack propagation morphology and fracture toughness. The results show that the shear stress at the crack tip is much greater than the tensile stress at the crack tip perpendicular to the prefabricated joint, the crack propagates along the original prefabricated joint, and the fracture toughness is independent of the initial fracture length. But it increases with the increase of the length and the decrease of the height. The crack tip of the four-point shear beam has the same size of shear stress and maximum principal stress. The crack starts at the tip of the prefabricated joint and extends near the loading point. The fracture toughness is independent of the geometric size of the specimen. With the increase of the initial joint length and the decrease of the distance between the near loading point and the prefabricated joint section, it increases.
【作者单位】： 南京水利科学研究院;
【基金】：国家自然科学基金(51325904,1279111)
【分类号】：TU528
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