基于PSO的中、下承式拱桥吊杆损伤识别与安全评定

发布时间：2018-03-26 07:22

本文选题：吊杆　切入点：损伤识别　出处：《武汉理工大学》2015年硕士论文

【摘要】：近年来,接连发生的中、下承式拱桥运营期安全事故中,由于吊杆损伤、断裂等原因引起的占了绝大多数,造成了重大的经济损失及人员伤亡,安全形势非常严峻。但与之相对应的是,现阶段吊杆的损伤识别及安全评定技术相对还比较落后,少数的无损检测手段和基于测试参数的损伤识别方法,无论在工程实用性还是识别准确性上都远远没有达到要求。因此,对中、下承式拱桥吊杆的损伤识别与安全评定研究有十分重要的理论意义和工程应用价值。本文以铜瓦门大桥为背景,采用中承式拱桥的有限元结构计算体系,研究了吊杆损伤与索力变化之间的理论关系,导出了索力变化列阵与损伤程度列阵关系的矢量表达式。在修正后有限元模型的基础上,对吊杆系进行损伤模拟,得到了中、下承式拱桥吊杆损伤与索力变化关系的一些基本特征,并利用上述基本特征,结合理论分析的成果,对吊杆损伤与索力变化的关系进行线性改造。进一步地,考虑测试误差的影响,建立了新的吊杆损伤预测模型。结合上述吊杆损伤预测模型,将粒子群优化算法(PSO)进行有针对性的改造。通过自编FORTRAN程序,解决了高维损伤向量的约束优化问题,建立了一套基于PSO的中、下承式拱桥吊杆损伤识别算法,从而可借助索力测量结果确定受损吊杆的位置和数量,并输出损伤程度信息。通过考虑多种损伤组合及不同程度误差干扰工况下的数值试验,表明该损伤识别方法具有较高的识别精度,并具有较好的鲁棒性。论文最后利用铜瓦门大桥的实测索力资料对全桥吊杆进行损伤识别,给出了全桥38根吊杆的损伤预报结果。以此为基础,提出了一套基于现存安全系数的中、下承式拱桥吊杆安全状况评定方法。该方法考虑了吊杆内力修正及吊杆抗力折减,并参考我国中、下承式拱桥吊杆安全系数的发展历史及现有的国家标准,制定了吊杆安全的分级评价准则,同时利用该方法对铜瓦门大桥进行了全面的吊杆安全评价。理论与实践效果表明,本文所提出的吊杆损伤识别及安全状况评定方法可以较好地描述吊杆现有的安全状态,且算法稳定,使用方便,可以在一定程度上提高中、下承式拱桥养护作业的水平。
[Abstract]:In recent years, in successive safety accidents of through arch bridges during operation period, most of them were caused by the damage and fracture of suspenders, resulting in heavy economic losses and casualties. The safety situation is very serious. However, the damage identification and safety assessment techniques of the suspenders are relatively backward at the present stage. A few methods of nondestructive testing and damage identification based on test parameters are used. In terms of engineering practicability and recognition accuracy, the requirements are far from being met. The research on the damage identification and safety assessment of the suspenders of the through arch bridge is of great theoretical significance and engineering application value. In this paper, the finite element structure calculation system of the middle through arch bridge is adopted in the context of the Tongwamen Bridge. In this paper, the theoretical relationship between cable force and cable force is studied, and the vector expression of the relation between cable force change array and damage degree array is derived. Based on the modified finite element model, the damage simulation of suspender system is carried out. Some basic characteristics of the relationship between through arch bridge hanger damage and cable force change, and by using the above basic characteristics, combining with the results of theoretical analysis, the relationship between suspension damage and cable force change is linearly modified. Considering the influence of test error, a new damage prediction model of suspension rod is established. The particle swarm optimization (PSO) algorithm is modified by combining the above damage prediction model of suspenders. The constrained optimization problem of high dimensional damage vector is solved, and a set of damage identification algorithm based on PSO for middle through arch bridge suspension is established. The position and number of damaged suspenders can be determined by the result of cable force measurement. The damage degree information is outputted. The numerical experiments under various damage combinations and different degree of error interference conditions show that the damage identification method has a high accuracy. Finally, using the measured cable force data of Tongwamen Bridge to identify the damage of the suspension rod of the whole bridge, the damage prediction results of 38 suspenders of the whole bridge are given. Based on the existing safety factor, a method for evaluating the safety of the suspenders of the through arch bridge is presented. The method takes into account the modification of the internal force of the suspenders and the reduction of the resistance of the suspenders, and refers to our country. The development history of through arch bridge suspender safety factor and the existing national standard, and the grading evaluation criteria of the suspender safety are established. At the same time, the comprehensive safety evaluation of the suspension rod of Tonghuamen Bridge is carried out by using this method. The theoretical and practical results show that, The method proposed in this paper can describe the existing safety state of the suspender, and the algorithm is stable and easy to use, which can improve the maintenance level of the through arch bridge to a certain extent.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446;U448.22

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