共查询到20条相似文献，搜索用时 15 毫秒
1.
The high-rise frame structure has become more and more widespread, like its damage from the complication of the environment. The traditional method of damage detection, which is only suitable for the stationary signal, does not apply to a high-rise frame structure because its damage signal is non-stationary. Thus, this paper presents an application of the short-time Fourier transform (STFT) to damage detection of high-rise frame structures. Compared with the fast Fourier transform, STFT is found to be able to express the frequency spectrum property of the time interval using the signal within this interval. Application of STFT to analyzing a Matlab model and the shaking table test with a twelve-story frame-structure model reveals that there is a positive correlation between the slope of the frequency versus time and the damage level. If the slope is equal to or greater than zero, the structure is not damaged. If the slope is smaller than zero, the structure is damaged, and the less the slope is, the more serious the damage is. The damage results from calculation based on the Matlab model are consistent with those from the shaking table test, demonstrating that STFT can be a reliable tool for the damage detection of high-rise frame structures. 相似文献
2.
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
3.
针对服役结构状态评估问题提出了基于虚功误差估计算子的统计分析方法.首先定义虚功误差来表达实际结构与参数化分析模型之间的差别,然后采用改进的牛顿算法推导分析模型结构识别算法.为了探讨在有测量误差的情况下算法的性能,引用Monte Carlo方法模拟测量数据,对测量数据的误差与识别结果的影响进行了详细的分析比较.根据识别结果确定它的概率分布,通过假设试验对服役结构状态评估进行统计分析.最后应用双跨五层刚架结构进行了大量数值模拟,计算结果显示了所提方法的有效性. 相似文献
4.
5.
Numerical prediction of statistical masonry wall fragment distribution induced by blast loading 总被引：1，自引：0，他引：1
The hazard caused by the fragments of damaged structures is usually significant in acci-dental explosions or hostile blast events.A reliable and efficient method to estimate probable fragment size,velocity and launch distance will be useful to assess and design countermeasures to mitigate the possible fragment hazards.This paper presents a numerical method for predicting the size and launch distance of the fragments caused by explosive damage of masonry wall.Numerical simulations with different scaled distances are carried out,and the statistical distribution functions of the fragment size and launch distance in terms of the scaled distance are derived. 相似文献
6.
董翔 《廊坊师范学院学报(自然科学版)》2014,(3):80-82
近年来,由于瓦片材质和结构的特殊性,使得此类屋顶在安装防雷设施时易造成瓦片损坏、屋面漏雨等质量问题,其防雷设施安装成为施工中亟需解决的技术难题.而使用卡座抱瓦式防雷网,既能保持仿古建筑物原有艺术风貌,又安全可靠、技术先进、经济投入合理. 相似文献
7.
Anna Parpala Sari Lindblom-Ylänne Erkki Komulainen Noel Entwistle 《Learning Environments Research》2013,16(2):201-215
The study examined the use of the modified Experiences of Teaching and Learning Questionnaire (ETLQ) in the Finnish context by focusing on its factor structures and comparing them with those for British data. A total of 2,509 Finnish and 2,710 British students completed the questionnaire. The comparison of the factor structures were conducted using exploratory structural equation modelling (ESEM) and a transformation analysis. Although the differences between the factor structures prevented a combined analysis, the structures were highly similar in the two contexts. The ETLQ appears to be a sufficiently robust and reliable instrument for use across countries and, in addition, at either the level of the degree subject or the single course module. 相似文献
8.
Based on pseudo strain energy density （PSED） and grey relation coefficient （GRC）, an index is proposed to locate the damage of beam-type structures in time-domain. The genetic algorithm （GA） is utilized to identify the structural damage severity of confirmed damaged locations. Furthermore, a systematic damage identification program based on GA is developed on MATLAB platform. ANSYS is employed to conduct the finite element analysis of com- plicated civil engineering structures, which is embedded with interface technique. The two-step damage identification is verified by a finite element model of Xinxingtang Highway Bridge and a laboratory beam model based on polyvi- nylidens fluoride （PVDF）. The bridge model was constructed with 57 girder segments, and simulated with 58 meas- urement points. The damaged segments were located accurately by GRC index regardless of damage extents and noise levels. With stiffness reduction factors of detected segments as variables, the GA program evolved for 150 generations in 6 h and identified the damage extent with the maximum errors of 1% and 3% corresponding to the noise to signal ratios of 0 and 5%, respectively. In contrast, the common GA-based method without using GRC index evolved for 600 generations in 24 h, but failed to obtain satisfactory results. In the laboratory test, PVDF patches were used as dynamic strain sensors, and the damage locations were identified due to the fact that GRC indexes of points near damaged ele- ments were smaller than 0.6 while those of others were larger than 0.6. The GA-based damage quantification was also consistent with the value of crack depth in the beam model. 相似文献
9.
The functional piezoelectric ceramic smart aggregate(SA) sensors and actuators,based on piezoelectric ceramic materials such as lead zirconium titanate(PZT),were embedded into the reinforced concrete beams with three-point bending under static loading for purposes of damage detection.The SA actuators generated the desired sine sweep excitation signals online and the SA sensors received and detected real-time signals before and after damage.The wavelet analysis and statistical characteristics about damage signals were used as a signal processing and analysis tool to extract the optimal damage information and establish a statistical damage detection algorithm.The damage index-based wavelet analysis and damage probability-based probability and statistics were proposed by PZT wavebased theory and active health monitoring technology.The results showed that the existence of cracks inside largely attenuated the amplitude of active monitoring signal after the damage of beam and the attenuation was related to the severity degree of damage.The innovative statistical algorithm of damage pattern detection based PZT-SA can effectively determine damage probability and damage degree,and provide a prediction for the critical damage location of reinforced concrete structures.The developed method can be utilized for the structural health comprehensive monitoring and damage detection on line of various large-scale concrete structures. 相似文献
10.
梁晓宏 《宁波职业技术学院学报》2005,9(5):40-42,60
针对配电网结构复杂、位置分散、数据采集困难等问题,提出了一种将嵌入式软硬件技术和基于GPRS（General Packet Rdtio Service）无线通信技术相结合的远程自动抄表系统,可自动完成用户电度表网络的远程数据采集、记录、实时监测、统计分析、打印和供电控制等管理工作.该设计系统构建简单,不受地理位置限制,性价比高,工作稳定可靠. 相似文献
11.
李静娟 《天津职业院校联合学报》2011,13(11):70-73
钢筋混凝土抗震结构不仅要满足强度要求,还必须满足延性要求。建筑结构的延性是保证建筑物在受到地震力、风力等荷载的作用下具有一定的耗能能力、产生可控塑性变形破坏、避免突然脆性破坏的主要条件。文章介绍了框架结构概念设计和延性设计的意义,通过分析多次震害框架结构破坏特点,提出了延性设计的一些思路和方法。 相似文献
12.
The soil-structure interaction (SSI) decoupling is applied to simplify buried structure against internal blast load as spring effect. Shear failure, bending failure and combined failure modes are considered based on five transverse velocity profiles for the rigid-plastic structural element. The critical equations for shear and bending failure are derived respectively. Pressureimpulse diagrams are accordingly developed to assess damage of the buried structures against internal blast load. Comparison is done to show influences of soil-structure interaction and shear-to-bending strength ratio of a structural element. A case study is conducted to show the application of damage assessment to a reinforced concrete beam element of buried structure. 相似文献
13.
引入一种动态性能较优的无偏导滤波器,针对其在GPS导航系统线性状态时的低精度表现,对单一的导航滤波器进行改进。采用一种组合滤波结构,根据GPS接收机的输出状态来进行线性及非线性滤波器的切换滤波。其中,线性滤波器采用优化的传统卡尔曼滤波器,并在仿真实验中验证其线性滤波优势;非线性滤波器采用了无偏导滤波器。车辆仿真实验表明,这种线性-非线性组合滤波器的误差低,运算量较小,整体滤波性能比单一滤波器高。 相似文献
14.
De-sheng WEN Zhi-li WANG Jun GAO Yong ZHANG Shi-jun LV Tetsuhiro TSUKIJI 《浙江大学学报(A卷英文版)》2011,12(4):301-309
The primary focus of this study was to investigate a series of novel motors and pumps, based on a new type of structure called
double-stator. The double-stator structure can be used as pump or motor just based on the application requirements. A certain
amount of pumps or motors can be formed in one shell, and these sub-pumps or sub-motors can work alone or be combined without
influence on each other. So this kind of double-stator pump (motor) is called a multi-pump (multi-motor). Through the analysis
of multifarious connection modes of the double-acting double-stator multi-pumps and multi-motors, the mathematical expressions
of the output flow rate and the rotational speed are acquired. The results indicate that a quantity of different flow rates
can be provided by one fixed-displacement multi-pump under the condition of unalterable driven speed by electromotor. Likewise,
when supplied by settled input flow, without complex variable mechanism, the functions of double-speed, multiple-speed, and
even differential connection can be obtained by employing the use of a double-stator multi-motor. The novel hydraulic transmission
is made of such a double-stator multi-pump and multi-motor, and has broad application prospects. 相似文献
15.
测断是对事物的实际情况不能做出确定反映时所采取的一种猜测性判断方式，它是比况结构的三大表义类型之一，其基本格式是“仿佛／好像X似的”；测断型比况结构只能由复句形式和谓词性短语构成，在复句中作分句，或者在单句中充当谓语和状语。 相似文献
16.
王琨 《福建工程学院学报》2021,(3):247-254
为解决危旧房屋状态的实时监测预警问题,设计了基于无线传感网的危房监测系统。利用加速度传感器实时采集房屋状态信息,改进传感器标定算法,采用温度分段式六位置标定法提高精度。数据传输采用射频通信和NB-IoT网络,根据实际房屋结构设计低功耗的路由算法,保证数据可靠传输。最终实现了高精度低功耗的远程监控方案,使决策者通过手机就能实时掌握房屋状态,提高房屋倾角监测精度,误差低于0.1°。 相似文献
17.
对国内外城市地下线形结构（地下管道、地下铁道和隧道等）震害的形式、成因及外部影响因素，如地震烈度、场地土条件、埋深、结构构造特点及尺寸等进行了综合分析．并就不同地下线形结构抗震措施的制订发表了见解。综合有关文献资料和工程实例．对盾构隧道进行纵向抗震分析，总结了地震区隧道结构的震害特点以及目前所采用的抗震措施，以供地震区隧道结构的设计、施工、加固作参考。 相似文献
18.
崔竹朝 《石家庄职业技术学院学报》2005,17(3):53-55
在由实词与实词组成的句法结构中，总是同时并存着两种结构关系：语法结构关系和语义结构关系。这是两种性质完全不同的结构，二者之间存在着错综复杂的关系，主要表现在：同一种语法结构可以表达多种语义结构；多种语法结构可以表达一种语义结构；同一种语法成分，可以有不同的语义指向；同一个句子，可以表现出不同的语法结构和语义结构。 相似文献
19.
在相邻结构间设置连廊通道将结构联系起来，传统的做法是采用悬挑断开的办法使各结构自成一体。本文从这类结构的特点出发，结合结构控制技术，考虑将结构连接起来，在连接体部分增加阻尼减震装置而形成一种联合成震体系．本文对联合减震体系的连接体的原理、设置方法、应用等进行分析． 相似文献
20.
心理弹性是一种处于逆境中能够克服危险因素,避免发展功能、适应能力、心理健康等方面受损的稳定的人格特质或能力。本文在积极心理健康教育视角下,在对心理弹性内在结构分析的基础上,就处境不利儿童心理弹性的危险性因素与保护性因素等问题进行了探讨,以期为改进处境不利儿童的教育提供依据。 相似文献