混凝土梁多裂缝断裂试验研究
发布时间：2018-08-15 12:28
【摘要】：裂缝是混凝土结构一个很主要的安全隐患,围绕混凝土裂缝的开裂及裂缝的扩展一直是国内外学者研究的重点。混凝土结构的破坏开裂是一个涉及到力学与材料学的综合问题。混凝土断裂力学是专门研究混凝土材料破坏开裂的一门学科,其引入许多新的关于裂缝问题的概念和方法,它比其他常规强度理论更适合于混凝土材料,它专注于混凝土材料本身的初始缺陷,分析在荷载作用下这种初始缺陷的发展规律,进而提出解决裂缝的安全设计准则。针对目前混凝土断裂问题研究存在的问题,本文通过试验研究与数值模拟进行了如下工作:(1)与其他成熟的工程学科相比,混凝土断裂力学仍然是一个发展中的领域,其很多研究还不成熟。本文在混凝土断裂理论研究成果的基础上,进行了跨高比S/D)= 4的三点弯曲断裂试验,试验过程中采集了荷载—裂缝张开口位移曲线(P-CMOD曲线)和荷载—位移曲线(P-δ曲线),使用P-δ曲线计算了三点弯曲试件的断裂能Gf,并依据试验数据进行了混凝土断裂韧度K1c的计算。(2)由于混凝土多裂缝问题的复杂性,本文进行了多个尺寸预制多裂缝混凝土梁的三点弯曲和四点弯曲试验,并探索了不同加载方式下试件断裂的破坏荷载、裂缝走向等问题。试验过程中采集了各条裂缝的荷载—裂缝张开口位移曲线(P-CMOD曲线),通过曲线分析,我们能清晰的了解到相同时刻各条裂缝的进展情况,同时,也记录了试件的破坏形态图。(3)依据试验测定的基础数据,建立数值计算模型,基于虚拟裂缝模型方法对试件进行数值模拟计算,并与试验结果进行对比分析,结果表明,数值模拟与试验结果基本吻合,验证了所用模型的正确性。
[Abstract]:Cracks are a major safety hazard in concrete structures. Cracks and crack propagation around concrete have been the focus of research by scholars at home and abroad. The discipline introduces many new concepts and methods about crack problems, which are more suitable for concrete materials than other conventional strength theories. It concentrates on the initial defects of concrete materials, analyzes the development law of such initial defects under load, and then puts forward safety design criteria for cracks. The following work has been done in this paper: (1) Compared with other mature engineering disciplines, the fracture mechanics of concrete is still a developing field, and many of its research is still immature. In the three-point bending fracture test, load-crack opening displacement curve (P-CMOD curve) and load-displacement curve (P-delta curve) were collected. The fracture energy Gf of three-point bending specimens was calculated by P-delta curve, and the fracture toughness K1c of concrete was calculated according to the test data. (2) Because of the multi-crack problem of concrete. In this paper, three-point bending and four-point bending tests of precast multi-crack concrete beams with different sizes are carried out, and the failure loads and crack strikes of specimens under different loading modes are explored. It can clearly understand the progress of each crack at the same time, and also record the failure pattern of the specimen. (3) According to the basic data measured by the test, a numerical calculation model is established. Based on the virtual crack model method, the numerical simulation of the specimen is carried out and compared with the experimental results. The results show that the numerical simulation and the test are carried out. The results are basically consistent and verify the correctness of the models used.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV331
[Abstract]:Cracks are a major safety hazard in concrete structures. Cracks and crack propagation around concrete have been the focus of research by scholars at home and abroad. The discipline introduces many new concepts and methods about crack problems, which are more suitable for concrete materials than other conventional strength theories. It concentrates on the initial defects of concrete materials, analyzes the development law of such initial defects under load, and then puts forward safety design criteria for cracks. The following work has been done in this paper: (1) Compared with other mature engineering disciplines, the fracture mechanics of concrete is still a developing field, and many of its research is still immature. In the three-point bending fracture test, load-crack opening displacement curve (P-CMOD curve) and load-displacement curve (P-delta curve) were collected. The fracture energy Gf of three-point bending specimens was calculated by P-delta curve, and the fracture toughness K1c of concrete was calculated according to the test data. (2) Because of the multi-crack problem of concrete. In this paper, three-point bending and four-point bending tests of precast multi-crack concrete beams with different sizes are carried out, and the failure loads and crack strikes of specimens under different loading modes are explored. It can clearly understand the progress of each crack at the same time, and also record the failure pattern of the specimen. (3) According to the basic data measured by the test, a numerical calculation model is established. Based on the virtual crack model method, the numerical simulation of the specimen is carried out and compared with the experimental results. The results show that the numerical simulation and the test are carried out. The results are basically consistent and verify the correctness of the models used.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV331
【参考文献】
相关期刊论文 前7条
1 张楚汉;唐欣薇;周元德;江汇;;混凝土细观力学研究进展综述[J];水力发电学报;2015年12期
2 徐世p，
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