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1.
苏英志 《邢台职业技术学院学报》2007,24(1):25-28
本文对基于模态振型的结构损伤识别方法进行了研究，提出一个新的模态参数——振型差值曲率，阐述了用它作为参数进行结构损伤识别的思想与方法，然后建立了一个悬臂梁的数值模型，用有限元分析计算结果作为损伤诊断的依据，对不同的模拟损伤用本丈所研究的方法进行了识别，结果表明采用振型差值曲率法可找到结构损伤的位置并确定结构损伤的程度，分析判断简便有效。 相似文献
2.
本文把基于旋转子空间算法的模态参数识别引入到梁桥结构损伤识别中。主要介绍了旋转子空间算法用于桥梁损伤识别的基本理论。旋转子空间算法是基于结构的有限元模型,利用矩阵变换的方法,将损伤位置和损伤程度问题区分开来,实际应用表明,只需利用一阶频率和振型,就可以识别桥的主要损伤位置和损伤程度。 相似文献
3.
近年来对结构的损伤分析方法甚多,本文利用ANSYS有限元软件对塔架结构的损伤进行数值模拟分析,基于结构损伤前后的振型数据,实现了对一平面塔架结构的较精确的损伤状态评估。数值模拟结果表明对塔架结构的损伤评估具有一定现实意义。 相似文献
4.
研究基于有限元模型的梁结构损伤识别的正反问题,即正问题采用有限元模型求解包含损伤位置和程度参数的结构前三阶固有频率,经曲面拟合技术拟合得到解曲面;反问题将实际损伤结构前三阶固有频率作为输入,绘制损伤梁结构位置和程度的等高线,根据曲线的交点识别出损伤梁结构损伤位置和程度。数值仿真算例表明:该方法具有足够的辨识精度,为梁类结构损伤识别提供了新方法。 相似文献
5.
对遗传算法在结构损伤诊断中的应用进行了分析。以单元刚度折减系数作为待识别参数,用频率误差和振型误差函数构建目标函数和适应度函数,运用遗传算法对折减系数进行计算,识别出结构损伤的位置和程度。实例分析表明了该方法的有效性和实用性。 相似文献
6.
基于信息融合技术的结构损伤诊断方法 总被引：1，自引：0，他引：1
为提高结构损伤识别的准确率,将多源信息融合技术引入到结构损伤诊断中．在介绍多源信息融合技术的基本理论、功能模型、级别分类和数学方法的基础上,将2种或多种结构损伤识别方法提取的损伤特征向量进行特征级融合,建立了基于信息融合的结构损伤诊断方法．在钢筋混凝土板损伤试验中测试其模态信息,利用基于信息融合的结构损伤诊断方法进行裂缝位置识别,并与单独使用模态应变能法和柔度法进行损伤识别的结果进行对比．结果显示基于特征级信息融合的结构损伤诊断方法能够准确识别单一损伤识别方法无法识别的结构损伤,对于多位置损伤识别亦有效果．基于信息融合的结构损伤诊断方法具有良好的损伤敏感性．不同的信息融合算法有不同的适用范围,在实际结构健康监测中,要通过详细分析选择合适的多源信息融合算法． 相似文献
7.
杨婷 《佳木斯教育学院学报》2014,(4):181+183
随着工业水平的不断发展和科学技术的不断进步,数值微分问题的正则化逐渐受到研究人员的重视。现如今正则化已经是数学领域的重要研究课题之一,尤其是近些年,相关的研究成果层出不穷。本文从数值微分和正则化的相关理论出发,简要分析了反问题与不适定问题的内涵,并对Fourier截断方法及修改核方法进行了一定程度的研究。 相似文献
8.
钢桁架结构损伤识别的频响函数曲率法 总被引：1，自引：0，他引：1
为了对桁架结构损伤情况进行比较准确的检测,采用频响函数曲率、频响函数曲率比、频响函数曲率差3个损伤识别指标,用ANSYS对桁架结构进行数值模拟分析,分别考虑了单处损伤、多处损伤,以及杆件出现损伤的确切位置,并且计算了在不同损伤程度下的损伤识别指标。结果表明:对于桁架结构,上述3种损伤识别指标都能检测出结构的损伤位置和损伤程度,但是频响函数曲率比检测的精确性最好,其不仅能检测结构的损伤位置、损伤程度,并且能够根据频响函数曲率比曲线图精确检测判断出结构具体损伤位置为哪一根杆件,为桁架结构的损伤检测增加了精确度。频响函数曲率和频响函数曲率差在进行损伤检测时会受到结构形式的影响,即离支座处越远,指标越不敏感,而频响函数曲率比则不会受到结构形式的影响,能够精确的检测结构的损伤情况。 相似文献
9.
《实验室研究与探索》2020,(8)
提出了一种基于挠度影响线奇异信号的损伤识别方法,利用静力作用下结构挠度影响线与刚度的关系,结合Hankel矩阵与奇异值分解的信号处理方法,建立了以各截面影响线奇异值为识别因子的损伤识别模型。编写了以Matlab为主控程序的损伤识别算法,同时完成了对一片装配式钢桁-砼组合梁进行多种损伤工况下的试验。结果表明:利用影响线奇异值作为损伤定性指标,结合其斜率变化率最大峰值位置与数值可有效识别组合梁损伤位置与程度。相比其他方法,该方法的损伤位置识别准确度高且抗噪性能强,损伤识别结果较为理想。 相似文献
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This paper proposes a new numerical simulation method for analyzing the parametric vibration of stay cables based on the theory of nonlinear dynamic response of structures under the asynchronous support excitation. The effects of important parameters related to parametric vibration of cables, i.e., characteristics of structure, excitation frequency, excitation amplitude, damping effect of the air and the viscous damping coefficient of the cables, were investigated by using the proposed method for the cables with significant length difference as examples. The analysis results show that nonlinear finite element method is a powerful technique in analyzing the parametric vibration of cables, the behavior of parametric vibration of the two cables with different Irvine parameters has similar properties, the amplitudes of parametric vibration of cables are related to the frequency and amplitude of harmonic support excitations and the effect of distributed viscous damping on parametric vibration of the cables is very small. 相似文献
12.
针对钛合金损伤在役监测需要,提出了采用声发射实时动态监测技术。利用有限元分析方法,通过建立钛合金板结构模型,并对其中不同类型、不同上升时间与不同传导距离的裂纹源开展研究,利用小波方法和频散曲线分析声发射源的特征频率与模态。仿真实验结果表明,在设定适当的上升时间与传导距离时,不同类型的声发射源有着不同的特征频率与模态,根据采集的数据可以对声发射源的类型进行判断。此外,随着上升时间的增加,模态特征识别难度加大,直至最终无法识别。不同传导距离对特征频率与模态表征的差异也比较明显。该研究结果可为进一步开展钛合金损伤实验提供参考依据。 相似文献
13.
WANG Yong HUANG Qi-bai ZHOU Ming-gang XIE Shou-yong 《重庆大学学报(英文版)》2006,5(3):125-130
1 Introduction ? Low frequency vibration has an important effect on body comfort and on the fatigue of a vibrating system. Nearly all actual vibrating systems are nonlinear. However, nonlinear behaviors are not always observed in the system dynamics. Thus… 相似文献
14.
Too many sensors and data information in structural health monitoring system raise the problem of how to realize multi-sensor information fusion. An experiment on a three-story frame structure was conducted to obtain vibration test data in 36 damage cases. A coupling neural network (NN) based on multi-sensor information fusion is proposed to achieve identification of damage occurrence, damage localization and damage quantification, respectively. First, wavelet packet transform (WPT) is used to extract features of vibration test data from structure with different damage extent. Then, data fusion is conducted by assembling feature vectors of different type sensors. Finally, three sets of coupling NN are constructed to implement decision fusion and damage identification. The results of experimental study proved the validity and feasibility of the proposed methodology. 相似文献
15.
姚程宽 《四川教育学院学报》2014,(3):118-121
Vapnik等人在统计学习理论和结构风险最小化的基础上提出了支持向量机算法（SVM）。该算法在高维模式识别、非线性、小样本等方面有较好的性能,已在许多领域取得了成功的应用。双正则化参数支持向量机的出现,更进一步提高了对于两类问题的研究成果。而利用样本数量来调整两个正则化参数C＋和C-的比值,这一方法也得到了较为广泛的应用和认可,特另13是在两类数据集中,即使这一理论没有经过严格的数学证明。文章以USPS数据库为基础,对之进行了大量的仿真实验,结果表明这个被广为接受的观点是不成立的。 相似文献
16.
对线性回归分类算法进行了改进。考虑了线性回归分类算法中没有考虑的类间信息,通过选择类模式的投影方向判别不同类的模式,不同类的模式互相远离,相同类的模式尽可能靠近来估计投影矩阵;再利用投影矩阵将训练图像及测试图像投影到各类的特征子空间;最后,计算出测试图像与训练图像间的距离,利用K-近邻分类器完成人脸的识别。在FERET人脸数据库上进行实验验证。实验结果表明,相比其他回归分类算法,本算法取得了更好的识别效果。 相似文献
17.
Solution to impedance distribution in electrical impedance tomography （EIT） is an ill-posed nonlinear inverse problem. It is especially difficult to reconstruct an EIT image in the center area of a measured object. Tikhonov regularization with some prior information is a sound regnlarization method for static electrical impedance tomography under the condition that some true impedance distribution information is known a priori. This paper presents a direct search method （DSM） as pretreatment of image reconstruction through which one not only can construct a regularization matrix which may locate in areas of impedance change, but also can obtain an initial impedance distribution more similar to the true impedance distribution, as well as better current modes which can better distinguish the initial distribution and the true distribution. Simulation results indicate that, by using DSM, resolution in the center area of the measured object can be improved significantly. 相似文献
18.
FENG Jinji XIE Qingliang ZHAO Dayong 《天津大学学报(英文版)》2006,12(B09):228-232
When hitting underground structures directly or exploding in rock-soil media near underground structures, the conventional weapons with large charge weight will make underground structures be subjected to strong shock vibration and cause personal casualty and damage of precision electronic equipments, The shock vibration has become one of the cardinal killing means of weapons. However, the existing methods of predicting structure shock vibration are limited evidently. In this paper the coupling coefficient of acceleration in clayey soil is obtained firstly. Subsequently based on repeated experiments of chemical explosion, after dimension analysis and by using method of multivariate stepwise regression, the calculation formulae of shock vibration acceleration for the underground structure are obtained finally. The formulae consider top and side explosion respectively, taking into account the effects of penetration depth, charge weight, distance to explosion center, rock-soil media, size of structure and buried depth. They are easy to use with high practicability and degree of confidence, and can provide credible evidence for prediction of shock vibration and vibration isolating design of underground structure. 相似文献
19.
When hitting underground structures directly or exploding in rock-soil media near underground structures, the conventional weapons with large charge weight will make underground structures be subjected to strong shock vibration and cause personal casualty and damage of precision electronic equipments. The shock vibration has become one of the cardinal killing means of weapons. However, the existing methods of predicting structure shock vibration are limited evidently. In this paper the coupling coefficient of acceleration in clayey soil is obtained firstly. Subsequently based on repeated experiments of chemical explosion, after dimension analysis and by using method of multivariate stepwise regression, the calculation formulae of shock vibration acceleration for the underground structure are obtained finally. The formulae consider top and side explosion respectively, taking into account the effects of penetration depth, charge weight, distance to explosion center, rock-soil media, size of structure and buried depth. They are easy to use with high practicability and degree of confidence, and can provide credible evidence for prediction of shock vibration and vibration isolating design of underground structure. 相似文献
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通过对齿轮箱正常和故障运行状态的振动信号进行分析,利用小波包理论将3种工况振动信号进行分解,根据不同频带内能量分布的不同以及能量比值指标,有效地进行了3种工况的识别与分类,结果表明,利用小波包分解是齿轮箱故障的一种有效的诊断方法。 相似文献