基于振动信息的结构损伤识别的几种新方法

发布时间：2018-01-11 08:01

本文关键词：基于振动信息的结构损伤识别的几种新方法　出处：《大连理工大学》2013年博士论文　论文类型：学位论文

【摘要】：基于振动信息的结构损伤识别通过对安装在结构上的传感器测得的振动响应信号采用某种算法进行分析来发现、定位、甚至定量损伤,具有可在线实时监测、快速定期检测、节省人力等优点；自20世纪70年代末期以来受到了广泛关注并取得了很大进展,已经提出了很多种结构损伤识别方法,但还面临着受噪声干扰大、对结构数值模型精确度有较大依赖、对损伤的敏感性有待提高等挑战。本文主要研究基于振动信息的结构损伤识别(损伤定位和损伤定量),重点发展不需要结构有限元模型(或对模型精确度依赖性低)、对环境和测试噪声不敏感且对结构损伤敏感的损伤识别方法,主要研究内容如下： (1)建立了适用于结构精细化和稀疏测点下损伤定位的SDLV法观测矩阵C的选择方法,从而提高了SDLV方法损伤定位的准确度。从SDLV法的核心(未知输入下Q矩阵的构造)入手,通过比较不同测点数比例下观测矩阵C对Q矩阵的影响,发现不同测点数比例时基于不同C矩阵构建的Q矩阵与损伤识别结果相关；为了减少传感器的使用数量,用力平衡的概念研究给出了基于SDLV法的两种常见桁架结构稀疏测点布置方案,实现了测点数量经济性和损伤识别精细化程度之间的平衡；为了实现对桁架结构关键杆件上局部损伤的定位,提出了基于SDLV法的结构关键构件精细化损伤定位方法和步骤；通过两种常见的桁架结构对以上内容进行了模拟和试验验证。 (2)提出了基于比例柔度矩阵的LU(QR)分解的结构损伤定位方法。柔度矩阵可以仅通过前几阶低阶模态参数构建,但需要己知结构输入(或至少在一个测点上已知输入)来获得质量归一化振型,这在实际中往往难以做到,本文采用结构比例柔度矩阵及其LU(QR)分解的结果,针对不同的结构对象构建不同的损伤指标进行损伤定位,并通过剪切型集中质量框架模型和桁架结构模型进行了模拟和试验验证。 (3)提出了四种目标函数和相应的结构损伤程度识别方法。运用以上两种方法可以发现并定位损伤,但未涉及损伤定量。针对损伤定量问题,选择损伤单元及其所在小范围的子结构脉冲响应和低阶振型为目标向量,借助有限元模型修正的方法,分别采用相关系数和模态保证准则分析模型修正结果中对应向量与目标向量之间的相似度,进而提出了四种结构损伤程度识别的目标函数和识别方法,并在简支梁模型和桁架结构模型上进行了模拟和试验验证。 (4)研究／提出了五种基于振动信息的损伤特征函数：分形维数、近似熵、对数加速度能量、离散度、急动度能量等；并且采用曲率差和概率平均的思想,分别提出了相应于每种损伤特征函数的平均归一化曲率差和归一化曲率差概率的结构损伤定位方法；在几个不同类型的结构仿真和试验模型上,分别进行了不同噪声水平下的模拟验证和试验验证。此外,基于以上几种损伤特征函数和进一步提出的“修正的对数加速度能量”损伤特征函数,研究了大跨度桥梁结构吊杆和斜拉索的损伤定位。结果表明：这些方法对损伤敏感、抗噪声能力强、不需要结构数值模型,避免了参数识别和建模过程中的误差。本文方法适用于基于实时监测(基于环境激励)或定期检测获得振动信息的结构损伤识别,验证模拟和试验的结构类型有：剪切型集中质量框架模型、梁结构模型、桁架(网架)结构模型、悬索桥结构算例、拱桥结构算例、斜拉桥结构算例等。
[Abstract]:Location of structural damage identification information through the vibration of the vibration sensor installed in the structure of the measured response signals by some algorithm were analyzed to identify, even based on quantitative damage, which can be real-time monitoring, fast periodic detection, save manpower and other advantages; since the late 1970s has attracted extensive attention and has made great progress. Have proposed a method of structural damage identification, but also face the noise interference, a greater reliance on the accuracy of the mathematical model of the structure, to improve the challenge to damage sensitivity.
Structural damage identification based on vibration information (this paper mainly studies the damage location and damage quantification), does not need to focus on the development of the finite element model (or the model accuracy, low dependence) on the environment and is not sensitive to noise test and damage identification method is sensitive to structural damage, the main research contents are as follows:
(1) selection method is established for the fine structure and sparse measurement SDLV method observation matrix C points of damage localization, which improves the SDLV method of damage localization accuracy. From the core SDLV method (Q matrix constructed under unknown input) to start, through observing the effects of C on different matrix Q matrix the proportion of measuring points under different measuring points, found that when the proportion of the Q matrix and the damage identification results of different C matrix construction based on correlation; in order to reduce the number of sensors used, given the concept of force balance in the location of two common sparse truss structure based on SDLV method, the number of measurement points between economy and damage identification of fine degree of balance; in order to realize the truss structure of key members on local damage location, put forward the key components of the structure by SDLV refinement method and steps based on the damage location by two; The above contents are simulated and tested by the common truss structures.
(2) put forward the proportional flexibility matrix LU (QR) based on structure decomposition method. The damage location can only through the flexibility matrix before a few low order modal parameters of construction, but the known structure of input (or at least in a measuring point on the known input) to obtain the mass normalized mode shapes, it is often difficult to achieve in practice, this paper adopts the structure of proportional flexibility matrix and LU (QR) decomposition results, according to the different objects of different construction damage index and damage location, through shearing lumped mass model and truss structure model were simulated and verified.
(3) put forward four kinds of objective function and the corresponding structural damage identification method. By using the above two methods can detect and locate damage, but not related to injury. For quantitative damage quantification, sub structure damage and the unit impulse response selection of small range and low order modes as the target vector, using the finite element model updating method, using the correlation coefficient and the modal assurance criterion analysis of similarity between the correction results in the corresponding model vector and the target vector, and then put forward the objective function and the recognition method of four kinds of structural damage identification, and simulation and experimental verification on beam and truss structure model.
(4) study / put forward five kinds of damage characteristic function based on vibration information: fractal dimension, approximate entropy, logarithmic energy dispersion, acceleration and jerk energy; and the idea of curvature difference and average probability, are proposed for structural damage localization average normalized curvature corresponding to each kind of function and damage characteristics the normalized curvature difference method in probability; structure simulation and test model of several different types, were simulated and tested under different noise levels. In addition, several damage characteristic function and further put forward the "modified logarithmic acceleration energy damage characteristic function based on the damage location of long-span bridges suspender and cable. The results show that the method is sensitive to damage and strong anti noise ability, does not need the mathematical model of the structure, to avoid the parameter identification and modeling The error in the process.
This method is suitable for real-time monitoring (based on structural damage identification based on environmental excitation) or regular detection to obtain the vibration information, type of structure to verify the simulation and test are: shearing lumped mass model of beam structure model, truss structure (grid) model of suspension bridge as an example, the arch bridge structure example, cable-stayed bridge the structure of the example.

【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU317

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