正对称荷载作用下单箱双室箱梁局部畸变效应的理论与试验研究

发布时间：2018-03-21 15:14

本文选题：双室箱梁　切入点：剪力流　出处：《兰州交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来，薄壁箱形截面梁的畸变效应作为一个重要课题，在桥梁结构设计和分析中不容忽视。本论文在国家自然科学基金：单箱多室箱梁的空间力学行为及一维梁段分析方法研究（51168030）和考虑索支撑作用的多室箱梁剪力滞效应研究（51368031）基金下进行研究的。针对正对称荷载作用下单箱双室箱梁的局部畸变效应问题，基于闭口薄壁杆件理论，进行了理论推导、理论计算、有限元数值模拟和有机玻璃模型试验等方面的研究及对比分析，主要研究内容如下：（1）针对正对称荷载作用下单箱双室箱梁，提出了将其截面的变形分解为剪力滞模式和扭转、畸变模式的组合变形，从扭转、畸变模式的变形中得到了正对称荷载作用下单箱双室箱梁截面在产生竖向弯曲变形的同时也有一定的局部扭转和畸变。本文以薄壁杆件理论和初等梁理论为基础，将中腹板处受集中荷载作用的单箱双室箱梁截面从荷载作用位置左右对称截开，根据截面弯曲剪力流平衡推导了截开后单室截面的等效荷载计算公式，利用荷载分解的方法从等效荷载中分离出了扭转荷载和畸变荷载，建立了截开后半截面的畸变控制微分方程和约束扭转控制微分方程，并通过弹性地基梁比拟法求得了截开后单室截面的畸变应力。（2）针对单箱双室简支梁在跨中截面和悬臂梁在自由端截面的中腹板处受集中荷载的情况，采用ANSYS有限元软件中的SHELL63单元建立了空间板壳有限元数值模型。从ANSYS软件输出的应力总值中利用荷载叠加的原理提取出了ANSYS板壳数值解，并将其与本文理论解进行了对比，大量对比分析表明，本文的理论解和有限元模型的ANSYS板壳解的变化规律和数值大小均基本接近，证实了本文的理论推导是正确的且具有很好的精度。（3）针对集中荷载正对称作用在单箱双室箱梁截面两边腹板上的情况，先使用荷载分解的方法将其等效成仅中腹板受力的荷载作用形式，再利用本文所提的理论计算出单箱双室箱梁截面的局部畸变应力并将其与ANSYS有限元数值解进行了对比分析，分析结果表明，本文的理论解和ANSYS有限元数值解吻合良好，这说明，将两种正对称荷载的作用形式利用荷载分解的方法等效成一种荷载作用形式的方法是可行的，同时也进一步反映了本文理论推导的正确性。（4）根据畸变应力与弯曲应力的比值，引入了畸变率的概念。通过对畸变率的分析得到：单箱双室截面顶板悬臂部位有最大的畸变率，而顶板和边腹板交接部位畸变率最小。仅中腹板加载时，简支梁跨中截面最大畸变率为32.16%，最小畸变率为8.94%；悬臂梁八分之一截面最大畸变率为56.36%，最小畸变率为18.89%。两边腹板正对称加载时，简支梁跨中截面最大畸变率为16.08%，最小畸变率为4.47%，悬臂梁八分之一截面最大畸变率为28.18%，最小畸变率为9.45%。结果表明，正对称荷载作用下单箱双室箱梁截面局部畸变应力在弯曲应力中占有很大的比例，在结构计算中不容忽视，同时还可以得出，正对称荷载在横截面分布越均匀，其截面局部畸变效应越不明显。（5）为进一步深入了解单箱双室箱梁的局部畸变问题，，利用有机玻璃建立了单箱双室简支箱梁室内模型。针对跨中截面受正对称集中荷载的三种作用形式，分别进行了模型加载试验，同样采用荷载叠加原理的从试验得到的应力总值中提取出了单箱双室箱梁截面局部畸变应力的试验值，并将截面局部畸变应力的试验值、ANSYS有限元数值解和本文理论解三方面进行了对比分析，分析结果表明，三者的变化规律和数值大小均吻合良好。
[Abstract]:In recent years, the distortion effect of thin-walled box girder as an important subject in the design and analysis of bridge structures should not be ignored. In this paper, the National Natural Science Foundation of China: Research on analysis method of single box multi cell box girder space and the mechanical behavior of one-dimensional beam section (51168030) and considering the shear lag effect of cable support. Multi cell box Research (51368031) research fund. According to local distortion effect is symmetrical load of single box double room box girder, closed thin-walled bar theory based on the theoretical derivation of the theoretical calculation, study and comparative analysis of finite element numerical simulation and model test of organic glass and other aspects of the main research the contents are as follows:
(1) the role of the symmetrical loading of single box double room box girder, the deformation of the section is divided into shear lag mode and torsional mode combined distortion, deformation, deformation from torsion, distortion model derived in the symmetrical load of single box double room box girder has some local torsion and in the production of vertical bending distortion at the same time. This paper is based on the theory of thin-walled member and elementary beam theory, the web load of single box double room box girder section from the loading position symmetrical cut, according to the section bending shear flow balance is cut after the equivalent load section the calculation formula of the load by the decomposition method of equivalent load from isolated torsion load and distortion load, a cut half section distortion control differential equation and the constrained torsion control differential equation, and the elastic Based on beam analogy method cut after distortion section stress.
(2) for single box double room beams under concentrated load in the bilge plate at mid span section and a cantilever beam section at the free end of the situation, to establish a finite element numerical model of space shell element of SHELL63 is used ANSYS finite element software. ANSYS software from the output of the stress in the use of gross load superposition principle to extract the numerical solution of the ANSYS shell, and compares it with the theoretical solution, a comparative analysis shows that the size variation and the value of the theoretical solution and the finite element model of ANSYS plate solutions are basically close to, confirmed the theoretical derivation is correct and has very good accuracy.
(3) the concentrated load is symmetrical in the single box double room box girder on both sides of the web, the first to be equivalent to the load force only in the form of web service load decomposition method, and then calculate the local distortion of single box double room box girder section stress and ANSYS Co. numerical solutions are compared with the theoretical analysis. The analysis results show that the theoretical solutions and numerical solutions of the finite element method are in good agreement with the ANSYS, which shows that the two kinds of symmetrical load form using equivalent load decomposition method into a load of form method is feasible, and at the same time further reflect the correctness of the theoretical derivation.
(4) according to the ratio of distortion and bending stress, introduces the concept of distortion. Through the analysis of distortion rate: single box double room section cantilever roof part has the largest distortion rate, while the roof and side distortion of Web junction of minimum rate. Only in the web is loaded, simply supported Liang Kuazhong section the maximum distortion rate is 32.16%, the minimum distortion rate is 8.94%; the 1/8 section maximum cantilever beam distortion rate is 56.36%, the minimum distortion rate of 18.89%. is symmetric loading on both sides of the web, beam cross section maximum distortion rate is 16.08%, the minimum distortion rate is 4.47%, the 1/8 section maximum cantilever beam distortion rate is 28.18%, the minimum distortion rate 9.45%. results showed that the positive symmetrical load of single box double room box girder distortion stress in the bending stress in the large proportion in structural calculation can not be ignored, at the same time, we can also see that the charge is called The more uniform the cross section distribution is, the less obvious the local distortion effect of the cross section.
(5) for further study of the problem of local distortion of single box double room box girder, a single box double room box girder model with the organic glass. According to the three form of cross section by symmetrical concentrated loads, respectively model loading tests were carried out, using the same load from the superposition principle the test can be extracted out of gross stress test of single box double room box girder distortion stress value, and the test section of local distortion stress values, ANSYS finite element numerical solution and the theoretical solution of three aspects of the comparative analysis, the analysis results show that the variation and the value size three are in good agreement.

【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

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