基于安全因子集的架桥机主梁结构伤损识别研究

发布时间：2018-03-21 23:02

本文选题：架桥机主梁　切入点：结构损伤　出处：《北京交通大学》2014年博士论文　论文类型：学位论文

【摘要】：摘要：架桥机是一种将预制钢筋混凝土梁段吊装在桥梁支座上的专用施工机械。架桥机一旦发生故障或事故,将会造成人员伤亡和巨大的经济损失,甚至是灾难性的后果。主梁是架桥机最主要的承载部件之一,其结构的安全性尤其重要,因此,对架桥机的主梁进行结构损伤识别具有重要的现实意义。分析了结构损伤的判断过程,构建了安全因子集,从定义、公式和判断依据三个方面对安全因子进行了详细的说明,并用模型梁作为算例,对安全因子的适用性进行了分析,找到了比较适合梁类结构的安全因子。介绍了布谷鸟搜索算法,从动态发现概率、步长和莱维飞行三个方面对其进行了改进,改进后的布谷鸟搜索算法收敛速度非常快,精度较高。并在此基础上提出了适用于高维函数的协同布谷鸟搜索算法。然后把损伤识别问题看作约束优化的数学问题,以固有频率和模态应变能建立目标函数,利用改进后的布谷鸟搜索算法进行损伤识别,并于其它算法进行对比,分析结果表明,改进后的布谷鸟搜索算法能较好的对架桥机主梁进行损伤识别。建立了基于核模糊C-聚类算法和多分辨小波核相关向量机的结构损伤模型,并且以频率变化率、模态应变能和加加速度等安全因子作为输入向量,分别对单损伤和多损伤样本进行无噪声和有噪声两种情况下的损伤识别,仿真结果表明该模型识别精度高、速度快。其次,利用提出的方法对损伤进行了预测分析,分析结果表明该方法有良好的预测能力。利用大型分析软件ANSYS建立架桥机主梁的有限元模型,对其进行网格划分,利用前面提到的安全因子集模拟不同的损伤工况并对他们进行分析,找到适合于架桥机主梁的安全因子,为大型施工机械的安全监测提供理论依据。对架桥机的主梁进行了损伤试验研究,采用矩形梁来模拟架桥机的主梁,分别进行了刚度试验、模态试验和动载试验,试验结果和仿真结果基本吻合。
[Abstract]:Absrtact: bridge erecting machine is a kind of special construction machinery which hoist precast reinforced concrete beam section on bridge support. Once the bridge erecting machine breaks down or accident, it will cause casualties and huge economic losses. The main beam is one of the most important load-bearing parts of the bridge erecting machine, and the safety of its structure is especially important. Therefore, it is of great practical significance to identify the structural damage of the main girder of the bridge erector. The process of judging structural damage is analyzed, the safety factor set is constructed, the safety factor is explained in detail from three aspects of definition, formula and judgment basis, and the applicability of safety factor is analyzed by using model beam as an example. The safety factors suitable for beam structure are found. This paper introduces the Cuckoo search algorithm, and improves it from three aspects: dynamic discovery probability, step size and Levy flight. The improved Cuckoo search algorithm converges very quickly. On the basis of this, a cooperative cuckoo search algorithm suitable for high dimensional function is proposed. Then the damage identification problem is regarded as a mathematical problem of constrained optimization, and the objective function is established by natural frequency and modal strain energy. The improved Cuckoo search algorithm is used for damage identification and compared with other algorithms. The analysis results show that the improved Cuckoo search algorithm can better identify the damage of the main girder of the bridge erecting machine. The structure damage model based on kernel fuzzy C- clustering algorithm and Multiresolution wavelet kernel correlation vector machine is established, and the safety factors such as frequency change rate, modal strain energy and additive speed are used as input vectors. The results of simulation show that the model has high accuracy and high speed. Secondly, the proposed method is used to predict and analyze the damage. The analysis results show that this method has good prediction ability. The finite element model of the main girder of the bridge erecting machine is established by using the large-scale analysis software ANSYS, and it is meshed. The safety factor set mentioned above is used to simulate the different damage conditions and to analyze them. The safety factors suitable for the main girder of bridge erecting machine are found, and the theoretical basis for safety monitoring of large construction machinery is provided. The damage test of the main girder of the bridge erecting machine is carried out. The rectangular beam is used to simulate the main beam of the bridge erecting machine. The stiffness test, modal test and dynamic load test are carried out respectively. The experimental results are in good agreement with the simulation results.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U445.36

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