损伤结构频域特性与定量诊断研究

发布时间：2019-06-03 18:58

【摘要】：框架结构是近些年来发展迅速的一种空间结构。这种结构适合于大空间、超大空间机械结构,投资巨大,往往是配置重要设施的场所。如果发生事故将可能引起重大的经济损失和生命危险。近年来发生了许多大跨度空间结构倒塌的实例。因此,如何检测和监测框架的运行状况有很大的实际意义。结构的检测有静力方法和动力方法,动力方法可以得到结构的频率、振型等参数,便于从整体上把握结构的运行性能,本文主要研究框架检测的动力方法。在框架结构众多的损伤当中,裂纹损伤是一种非常普遍的机械损伤。本文以简单的框架结构模型的仿真研究为基础,通过仿真得出框架出现裂纹时的频率、振型等动态参数,并根据这些参数分析框架结构的频域特性,根据框架结构有裂纹时和没有裂纹时的频域特性对框架结构的裂纹位置进行检测。以框架结构为研究对象,结合ANSYS有限元软件,采用有限单元法对框架结构进行单元节点划分,运用APDL语言在ANSYS软件中建立起了空间框架结构的有限元模型。对框架结构进行模态分析、时域分析,研究裂纹对结构振动的振型产生的影响。分别以悬臂梁结构和框架结构为研究对象,进行了裂纹位置的诊断。提出了一种新的裂纹定位法,并通过计算和仿真验证了该方法的有效性。最后,考虑到实际检测中,框架结构自由度数目巨大,不可能得到所有自由度上的振动信息,会遇到测量模态不完备的情况,文中分析了传感器的优化布置,以及得到不完备测量数据后如何对框架结构的运行情况进行评估。提出了基于有效独立法来确定裂纹的监测点的位置,并通过仿真对比了随机选取监测点的位置与按有效独立法确定监测点的位置所得到的结果,证明了有效独立法的可行性。
[Abstract]:Frame structure is a kind of spatial structure with rapid development in recent years. This structure is suitable for large space, large space machinery structure, huge investment, often equipped with important facilities. If an accident occurs, it may cause great economic loss and life danger. In recent years, many examples of collapse of long-span spatial structures have occurred. Therefore, how to detect and monitor the operation of the framework has great practical significance. There are static and dynamic methods for structural detection. The dynamic method can obtain the frequency, vibration mode and other parameters of the structure, which is convenient to grasp the operation performance of the structure as a whole. In this paper, the dynamic method of frame detection is mainly studied. Among the many damage of frame structure, crack damage is a very common mechanical damage. In this paper, based on the simulation of a simple frame structure model, the frequency, vibration mode and other dynamic parameters of the frame structure when cracks occur are obtained by simulation, and the frequency domain characteristics of the frame structure are analyzed according to these parameters. According to the frequency domain characteristics of the frame structure with and without cracks, the crack position of the frame structure is detected. Taking the frame structure as the research object, combined with ANSYS finite element software, the finite element method is used to divide the element nodes of the frame structure, and the finite element model of the spatial frame structure is established in ANSYS software by using APDL language. The modal analysis and time domain analysis of the frame structure are carried out to study the influence of cracks on the vibration mode of the structure. The crack position of cantilever beam structure and frame structure is diagnosed respectively. A new crack location method is proposed, and the effectiveness of the method is verified by calculation and simulation. Finally, considering that in the actual detection, the number of degrees of freedom of the frame structure is huge, it is impossible to obtain the vibration information on all degrees of freedom, and the measurement mode is incomplete. The optimal arrangement of the sensor is analyzed in this paper. And how to evaluate the operation of the frame structure after obtaining the incomplete measurement data. The position of the monitoring point of the crack is determined based on the effective independence legislation, and the results obtained from the random selection of the monitoring point and the position of the monitoring point determined by the effective independent legislation are compared by simulation, which proves the feasibility of the effective independent legislation.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU317

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