部分预应力混凝土梁疲劳性能试验研究及数值模拟

发布时间：2018-03-07 02:00

本文选题：部分预应力混凝土梁　切入点：疲劳性能　出处：《大连理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：目前,预应力混凝土梁在我国获得了广泛的应用,尤其是在大跨度和对裂缝及挠度控制较严的结构中。对于混合配筋的预应力混凝土结构,由于在服役期间受到静力荷载和动力荷载的双重影响,导致其疲劳问题更加突出。本文结合国家高新技术研究发展规划(863计划)“基于疲劳和寿命的混凝土桥梁结构设计方法”(2007AA11Z133)专项课题,针对部分预应力混凝土梁的疲劳性能研究,做了如下几个方面的工作： (1)在试验的基础上研究了部分预应力混凝土梁的疲劳性能。讨论了部分预应力混凝土梁疲劳破坏的形态和特征,研究了梁顶混凝土压应变、钢筋应变、裂缝在疲劳荷载作用下发展的一般规律,发现三者随疲劳荷载次数的增加呈三阶段增长,即初期和后期增加较快,中期增长缓慢,为疲劳发展的主要阶段。 (2)根据试验数据,分析了构件疲劳荷载下残余挠度和瞬时挠度的变化规律,并考虑其主要因素,分别建立了相应的计算公式,从而得到了整个疲劳寿命内不同次数下的总挠度计算公式。分析了导致疲劳破坏前总挠度增大的影响因素,得到了总挠度增大系数的计算公式。 (3)进行了部分预应力混凝土梁的静力数值模拟。首先介绍了大型有限元分析软件ANSYS和主要用于钢筋混凝土结构中的单元类型,其次介绍了静力模拟所用的本构关系、材料模型和模型的建立及相关加载求解设置,并根据模拟结果和试验结果进行了对比,验证了模型的正确性,为疲劳性能数值模拟奠定了基础。 (4)根据材料和构件在疲劳荷载下的损伤规律,建立了用于部分预应力混凝土梁模拟的疲劳本构关系和预应力损失模型,并建立了用于判断材料失效的破坏准则,提出了可用天疲劳全过程分析的数值模拟方法,将疲劳数值模拟结果和试验结果进行了对比与分析,发现两者误差较小且变化规律相同,表明本文建立的疲劳模型的准确性。
[Abstract]:At present, prestressed concrete beams have been widely used in our country, especially in long-span structures with strict control of cracks and deflection. Due to the dual effects of static and dynamic loads during service, Therefore, the fatigue problem is more prominent. In this paper, the fatigue performance of partially prestressed concrete beams is studied according to the National High-Tech Research and Development Program, "Design method of concrete Bridge structure based on fatigue and Life". Work has been done in the following areas:. 1) the fatigue behavior of partially prestressed concrete beams is studied on the basis of tests, the fatigue failure patterns and characteristics of partially prestressed concrete beams are discussed, and the compressive strain of concrete and the strain of reinforcement on the top of beams are studied. The general law of crack development under fatigue load shows that the three phases increase in three stages with the increase of fatigue load times, that is, the increase of initial and late stage is faster, and the growth of middle period is slow, which is the main stage of fatigue development. 2) based on the experimental data, the variation law of residual deflection and instantaneous deflection under fatigue load is analyzed, and the corresponding calculation formulas are established considering the main factors. The formulas for calculating the total deflection at different times in the whole fatigue life are obtained, and the influencing factors leading to the increase of the total deflection before fatigue failure are analyzed, and the calculation formula for the coefficient of the total deflection increase is obtained. In this paper, the static numerical simulation of partially prestressed concrete beams is carried out. Firstly, the large finite element analysis software ANSYS and the element types mainly used in reinforced concrete structures are introduced. Secondly, the constitutive relations used in static simulation are introduced. The establishment of material model and model and the setting of relevant loading solution are compared according to the simulation results and experimental results. The correctness of the model is verified and the foundation for the numerical simulation of fatigue performance is established. 4) according to the damage law of materials and members under fatigue load, the fatigue constitutive relation and prestress loss model of partially prestressed concrete beams are established, and the failure criteria are established to judge the failure of materials. In this paper, a numerical simulation method for the analysis of the whole fatigue process is put forward. The comparison and analysis of the fatigue numerical simulation results and the experimental results show that the error is small and the variation law is the same, which indicates the accuracy of the fatigue model established in this paper.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU378.2

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