【作者】 花尉攀；

【导师】 狄生奎；

【作者基本信息】 兰州理工大学 ， 桥梁与隧道工程， 2010， 硕士

【摘要】 大多数的工程结构,在遭受到地震、火灾等自然灾害或者长期的疲劳荷载和腐蚀作用下,常常会引起结构损伤,随着损伤的积累,其危险程度也逐步提高。结构损伤判断及损伤位置的确定,可以帮助人们对结构进行实时修复或改变结构的操作使用方法,以便降低结构的损伤积累程度,减少经济损失。结构损伤识别是土木工程中一个新兴的研究方向,尚未形成统一的求解理论与方法,仍处于发展的起步阶段。本文运用曲率差模态方法对梁桥结构的损伤识别问题进行研究,共分五章,具体研究内容如下：(1)阐述了桥梁结构损伤识别的意义、内容和方法,以及现阶段国内外在损伤识别领域的研究现状和研究成果,并且介绍了本文的研究范围和主要研究内容。(2)论述大型桥梁的健康监测与安全检测的内容,以及健康监测与安全检测的理论,阐述桥梁结构健康监测的重大意义。(3)简支梁在不同荷载工况下,利用结构力学中的虚功原理,来推导简支梁桥在损伤前后曲率差公式,得出简支梁曲率差模态指标与损伤位置和损伤程度有关结论,并介绍应变和曲率的关系,从而说明用振型和应变两种方法都可以求曲率,为曲率差模态在实际检测过程中提供了理论基础,证明了该方法对结构的损伤定位有较高的准确性和敏感性。(4)较详细地论述曲率模态分析的理论基础,分析了曲率模态、应变模态和模态振型之间的关系；分别用振型模态和应变两种方法求曲率模态,采用曲率差模态法对简支梁模型进行损伤仿真模拟计算,文中将分五种工况进行分析,研究和对比了单一损伤位置和多处损伤位置的损伤识别能力,以及不同损伤程度对于结构损伤识别的影响等,并研究了损伤前后结构固有频率的变化情况。数值模拟结果验证了曲率差模态损伤识别指标对梁桥损伤识别的可行性、有效性和适用性。(5)用试验的方法验证曲率差模态在现实测试中的有效性。(6)总结了本文的研究内容和成果,并指出运用曲率差模态损伤识别指标在桥梁结构损伤识别和健康监测中存在的问题。更多还原

【Abstract】 Most of the engineering structures,when subjected to the natural disasters such as earthquake, fire and the action of the long-term fatigue loading or erosion, the damage of the structure is caused.With the accumulation of the damage,its criticality will be enhanced gradually.After judging the structure damage and confirming the locality of the damage, real time repair can be done or the means of the operation of changing the structure can be changed,so as to reduce the accumulation degree of the damage of the structure and the economy loss.Structural damage detection in civil engineering is a new research field, which has not yet formed a unified theory and method of solving, and is still in the initial stage of development. In this paper, damage identification of bridge structure is studied by using the difference of modal curvature methods.The paper is divided into five chapters.Specific studies are as follows:(1)Described the significance, contents and methods of the damage identification of bridge structure, research status and results of damage identification in China and abroad, and the scope of the paper and the main research contents.(2)Discussed the health monitoring of large bridge and the contents of safety testing, as well as the theories of health monitoring and safety testing, and explaining the great significance of bridge structural health monitoring.(3)While simply supported beam suffer with different load conditions,the virtual work principle of structural mechanics are used to deduce the damage formula of simple beam bridge before and after the curvature difference, obtain index of the modal curvature difference and damage location and degree of injury of simple supported beams. The relationship between strain and curvature, which can work out the curvature by using mode shape and strain are described, and provided a theoretical basis for the process of the curvature difference in the actual detection, which proves the higher positioning accuracy and sensitivity of the method of locating the damage of structure.(4) Discussed the theoretical basis of curvature modal analysis in detail,analyzed the relationship of curvature modal, strain mode and mode shapes;respectively used mode shape and strain method to seek curvature mode, and used the curvature difference modal method to do analogy computation to the damage of simply supported beam.The working conditions are divided into five types to analyze research and compare the identification capabilities of single damage location and multiple damage locations under different conditions,and the impact of different injury degrees to structural damage detection etc.The changes of the damage before and after the natural frequency are also studied.Numerical simulation results show the feasibility, validity and applicability of the index of curvature difference modal damage detection to bridge damage identification.(5)The effectiveness and applicability of curvature difference modal in the real test is verified by experimental method.(6)Summarized the contents and results of this paper, and pointed out the problem in using the difference of mode curvature damage identification in the bridge structure damage identification and health monitoring.更多还原