基于曲率模态关联系数的损伤识别研究

发布时间：2018-05-04 12:41

本文选题：钢筋混凝土梁 + 曲率模态　；参考：《昆明理工大学》2014年硕士论文

【摘要】：桥梁是非常重要的基础设施,它对地方经济发展有重要的作用,为人们的日常出行提供便利。近年来大型桥梁垮塌不断出现,此类事故一旦发生不但会带来巨大的经济损失,而且威胁到人民群众的生命安全,在这种背景下桥梁损伤检测自然成为国内外学者研究的热点。时至今日,桥梁损伤识别经过几十年的发展,并且获得很大进展,如传感器的灵敏度有所增加、和损伤相关的参数不断被发现,所以可供选择的方法也日益增加,但是依然存在很多问题,本文在此基础上对钢筋混泥土梁的损伤识别方法进行了研究。文中将曲率模态作为损伤识别参数,将它和灰色系统理论联系在一起。论述了利用曲率模态关联系数识别损伤的理论基础。并提出一种改进的关联系数计算方法,这种方法避免了分辨系数对结果的影响。论文用ANSYS软件对钢筋混凝土梁进行了三维模拟。从中提取位移模态并求得曲率模态,以计算曲率模态关联系数的方式识别其损伤,通过对比不同情况下的关联系数曲线,得到了以下结论：结构损伤越大关联度突变越明显；可以由此判断损伤程度。距离损伤点近的节点关联系数也会降低；距离损伤点越远的地方关联度越接近1,可以由此判断损伤位置。接下来进行模态分析试验。实验对象是四根2m长的钢筋混凝土梁,其中一根是完好梁,其他三根依次是跨中损伤5%、跨中损伤10%、四分之一跨损伤5%。实验手段如下：通过激励实验梁,测得其速度-时间曲线,对它进行FFT变换得到频率-振幅曲线。最后由峰值检测和差分运算计算出结构的曲率模态。然后详细说明了计算曲率模态关联系数的步骤,并通过结果对比进一步证明了上一章提出的结论。
[Abstract]:Bridge is a very important infrastructure, it plays an important role in the development of local economy and provides convenience for people's daily travel. In recent years, large bridge collapses continue to appear. Once such accidents occur, they will not only bring huge economic losses, but also threaten the lives of the people. Under this background, bridge damage detection has naturally become a hot spot of domestic and foreign scholars. Nowadays, bridge damage identification has been developed for decades, and great progress has been made, such as the sensitivity of sensors has increased, and the parameters related to damage have been found constantly, so the available methods are increasing day by day. However, there are still many problems. On this basis, the damage identification method of reinforced concrete beams is studied in this paper. In this paper, curvature mode is regarded as the damage identification parameter, which is connected with the grey system theory. In this paper, the theoretical basis of identifying damage by using curvature modal correlation coefficient is discussed. An improved method for calculating the correlation coefficient is proposed, which avoids the influence of the resolution coefficient on the result. In this paper, three-dimensional simulation of reinforced concrete beam is carried out with ANSYS software. The displacement mode is extracted and the curvature mode is obtained, and the damage is identified by calculating the curvature modal correlation coefficient. By comparing the correlation coefficient curves under different conditions, the following conclusions are obtained: the bigger the structural damage is, the more obvious the sudden change of the correlation degree is; The degree of injury can be judged accordingly. The correlation coefficient of the node near the damage point will also be reduced, and the closer the distance from the damage point is, the closer the correlation degree will be, which can be used to judge the location of the damage. Then the modal analysis test is carried out. The experimental objects are four reinforced concrete beams with 2m length, one of which is a intact beam, the other three are in turn 5 in the middle span, 10 in the middle of the span, 5 in the 1/4 in the span. The experimental methods are as follows: by exciting the experimental beam, the velocity-time curve is measured, and the frequency-amplitude curve is obtained by FFT transformation. Finally, the curvature mode of the structure is calculated by peak detection and differential operation. Then, the steps of calculating the curvature modal correlation coefficient are explained in detail, and the conclusion in the previous chapter is further proved by comparing the results.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U446;U448.34

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