特高压输电塔的损伤识别.DOC

1、特高压输电塔的损伤识别重庆大学硕士学位论文学生姓名：朱汉棠指导老师：郭惠勇 副教授专 业：工程力学学科门类：工 学重庆大学土木工程学院二 O 一 O 年五月Damage Detection of UHV Transmission TowerA Thesis Submitted to Chongqing Universityin Partial Fulfillment of the Requirement for theDegree of Master of EngineeringByZhu HantangSupervised by Ass. Prof. Guo Huiyong Major: E

2、ngineering MechanicsCollege of Civil Engineering ofChongqing University, Chongqing, ChinaMay, 2010中文摘要I摘 要因为建筑材料中存在着各种各样的缺陷和结构投入使用后一切不可预计的外力的影响，所以结构破损是在所难免的。为了在结构出现严重破坏或者倒塌之前发现这些缺陷和损伤并加以处理避免灾难发生，人们开始对结构进行损伤检测和健康监测等研究。但现阶段的损伤检测方法仍然存在许多缺点，对大型复杂结构（如输电塔结构）无法一步将损伤的位置和程度同时识别出来，而且对称性和噪声对结构损伤识别影响亟待解决。所以多种方法

3、结合，分步多层次交叉识别方法是复杂结构损伤识别的关键。本文以江汉大跨越输电塔为例，提出了基于模态应变能理论和曲率模态理论的两步结构损伤检测方法，主要内容和结论如下： 将曲率模态理论和灰色理论相结合，提出基于振型曲率置信因子的结构损伤定位方法。并对其的识别效果进行分析，发现该方法对大小损伤之间的差距要求不高，只要最大损伤不比最小损伤的损伤程度大 70 个单位，识别效果仍然为理想；但是对噪声影响比较敏感。 利用模态应变能变化概率对结构进行损伤定位分析，识别结果表明该方法对多损伤时损伤之间的差距比较敏感，但抗噪声能力强。 比较上述两种损伤定位方法的优缺点，然后利用信息融合技术将两种方法融合起来进行损

4、伤定位识别。结果表明融合信息法能够有效地发挥两种方法的优点，降低噪声的影响，提高损伤定位能力。 基于模态应变能耗散率的损伤识别方法可以同时进行损伤定位和定量识别。因为结构损伤后的单元刚度矩阵一般是无法获得，所以该方法假设损伤后单元刚度矩阵不变。但是实际情况中损伤后单元刚度矩阵不可能不改变，因此该方法损伤定量结果存在相当大的误差。虽然该方法损伤定量效果不理想，但是对损伤位置比较敏感，可以用于校核前面的损伤定位结果。 为了提高损伤程度的识别能力，本文引入了结构损伤后单元刚度矩阵推导出关于损伤变量（即损伤程度）的一元四次方程，通过求解该一元四次方程可以计算出单元损伤程度。该改进方法有效避免了假设损伤

5、前后单元刚度矩阵不变带来的误差，同时大大提高了损伤定量识别能力。但是该方法对损伤位置非常不敏感，需要结合识别能力较强的损伤定位方法解决输电塔损伤识别问题。关键词：损伤识别，输电塔结构，曲率模态，模态应变能，耗散率重庆大学硕士学位论文II英文摘要IIIABSTRACTMany defects inevitably exist in structural materials, and the structure will come across all kinds of unpredictable forces during use, so the structure will inevitabl

6、y have different levels of damage. In order to find out the flaws and damages before collapse and serious damage, people begin to study the damage detection and health monitoring technology. But the damage detecting method which are used recently still have many shortcomings. It can not find the dam

7、age location and damage degree in one step for large scale and complex structures (for example, the transmission tower). And the influence of the symmetry and noise for damage detection is very important which we have to solve right away. So the integration of many detection method and multi-stage d

8、etection method is the key to complex structural damage identification. This paper use JiangHan transmission tower as an example, and proposed two-step structural damage detection method based on modal strain energy theory and curvature mode theory, the main contents and conclusions are as follows:

9、1 Structural damage location method based on confidence factor of curvature mode shape is applied through combining the curvature mode theory and gray theory. And then, analyzing the effect of the method, we found that the size of the gap between the damages is not important for the method. The reco

10、gnition effect is still very ideal as long as no more than 70 units of damage gap. But the damage location method is sensitive to noise. 2 Structural damage location analysis used changing probability of mode strain energy is applied. The damage recognition results show that this damage location met

11、hod is sensitive to damage gap but noise. 3 Comparing these two kinds of damage location methods above-mentioned, and then, we use information fusion technology to combine two kinds of methods for damage location identification. The damage recognition results show that information fusion method can

12、effectively plays advantage of the two methods above-mentioned, and reduces the noise influence, improves the damage location capability. 4 Structural damage identification method based on the modal strain energy dissipation rate can also for damage location and degree identification. Element stiffn

13、ess matrix is generally cannot receive, so this method assumes stiffness matrix 重庆大学硕士学位论文IVof structure after injury is constant. But after the injury situation of element stiffness matrix could not unchanged, so the method of degree identification results exist very big error. This methods damage

14、degree identification effect is not ideal, but is sensitive to damage location, and can be used to check the damage location identification results obtained in front. 5 In order to improve the ability to identify the damage degree, this paper introduced structure stiffness matrix to deduce a quartic

15、 equation about damage variable (i.e., the degree of damage), and we can calculate the degree of damage by solving the equation. The improved method is effective to avoid the error from assumed stiffness matrix of structure after injury is constant, and constant greatly improves the ability to ident

16、ify the damage degree. But this method is not sensitive to damage location, need to combine a strong ability to identify the damage location method to solve problems transmission tower damage identification. Keywords: damage identification; transmission tower; curvature mode; modal strain energy; di

17、ssipation rate 目 录V目 录中文摘要 .I英文摘要 .III1 绪 论 .11.1 选题背景及意义 .11.2 结构损伤检测研究综述 .21.2.1 结构损伤检测方法综述 .21.2.2 结构损伤动力识别的参数 .71.3 大型复杂结构的损伤检测研究综述 .81.4 本文的主要研究内容 .92 工程概况 .112.1 输电塔有限元模型建立 .112.1.1 基本假定 .112.1.2 模型简化 .112.1.3 模型建立 .112.2 模态计算 .122.3 损伤识别总说明 .143 结构损伤定位研究 .193.1 基于灰色相关性的结构损伤定位 .193.1.1 灰色理论 .1

18、93.1.2 曲率模态 .193.1.3 灰色振型曲率关联系数 .213.1.4 基于振型曲率置信因子的损伤定位分析 .213.2 基于模态应变能变化概率的结构损伤定位 .323.2.1 模态应变能变化概率定位法原理 .323.2.2 基于模态应变能变化概率的结构损伤定位 .333.3 曲率模态方法和模态应变能方法的比较 .463.4 基于信息融合技术的损伤定位改进 .473.4.1 信息融合 .473.4.2 D-S 证据理论基本原理 .483.4.3 基于模态应变能和曲率模态信息融合的损伤定位 .493.5 本章小结 .564 结构损伤定量研究 .57重庆大学硕士学位论文VI4.1 模态应变能耗散率理论 .574.2 基于模态应变能耗散率的结构损伤定量 .584.3 基于模态应变能耗散率理论的损伤识别方法的改进策略 .684.4 基于改进方法的结构损伤定量 .694.5 本章小结 .805 结论与展望 .81致 谢 .83参考文献 .85附 录 .91作者在攻读硕士学位期间发表论文的目录 .91