基于小波和振动模态分析的正放四角锥网架结构损伤检测研究
发布时间：2018-08-07 16:04
【摘要】：近些年来,我国在经济迅速发展的推动下,建筑技术不断提高,建成了一大批规模宏大、形式新颖的大跨度空间结构(如体育馆、航站楼、展览中心等)。由于大跨度空间结构往往人群聚集,而且有些场所配置重要设施,因此结构一旦出现损伤、发生破坏将造成重大的人员伤亡事故。大跨空间结构(如网架结构、网壳结构等)在设计使用年限内,除长期受自重等恒荷载的作用外,还承受环境侵蚀、爆炸、地震和冲击等作用,造成结构构件的疲劳积累、抗力衰减和材料老化等问题,使结构的实际刚度退化,当损伤积累到一定程度就有可能造成结构整体破坏,历史上曾经发生过许多大跨空间结构倒塌的事故。因此,为防止结构倒塌事故的发生,避免发生重大的安全事故和经济损伤,对大跨空间结构进行定期的检测十分必要。 鉴于以上原因,本文主要作了以下研究工作: 1)利用有限元软件ANSYS对钢悬臂梁结构进行损伤分析。首先采用瞬态激励法提取有用信息,构造损伤参数(单元应变模态差和单元模态应变能变化率),然后选取小波函数,对损伤参数进行小波变换,最后进行结构损伤位置判定。为了验证数值模拟的有效性,本文利用实验室仪器设备,对钢悬臂梁实物进行了动力模态测试,将实际实验数据与数值模拟结果进行对比,进而说明数值模拟的有效性。 2)由于在实际检测中采集的信号往往夹杂噪声信号,为了获得更好的损伤检测信号,本文采用小波阈值和MATLAB软件相结合的方法进行信号消噪的模拟研究,将消噪方法应用到实验采集信号中,还原原始信号,进行结构损伤识别。 3)利用有限元软件ANSYS对正放四角锥网架结构进行损伤模拟分析。首先选取最优激励位置,应用单点瞬态激励进行完好结构和损伤结构的数值模拟,然后采集模拟信号,以单元模态应变能变化率作为损伤参数,最后对损伤参数进行小波变换,进而进行结构损伤位置判定。
[Abstract]:In recent years, with the rapid development of economy, the construction technology has been improved, and a large number of large-scale and novel long-span spatial structures (such as gymnasium, terminal building, exhibition center, etc.) have been built. Because large span spatial structures are often crowded with people and some places are equipped with important facilities, once the structure is damaged, the damage will cause serious casualties. Large span space structures (such as latticed structures, latticed shell structures, etc.) are subjected to environmental erosion, explosion, earthquake and shock, in addition to being subjected to constant loads such as self-weight for a long time in their design life, resulting in the fatigue accumulation of structural members. The problems of resistance attenuation and material aging make the actual stiffness of the structure degenerate. When the damage accumulates to a certain extent it is possible to cause the overall damage of the structure. Many accidents have occurred in the history of collapse of the long-span space structure. Therefore, in order to prevent the collapse of structures and avoid the occurrence of major safety accidents and economic damage, it is necessary to carry out periodic detection of long-span space structures. In view of the above reasons, the main work of this paper is as follows: 1) the damage analysis of steel cantilever structure is carried out by using finite element software ANSYS. First, the useful information is extracted by transient excitation method, and the damage parameters (strain mode difference of element and strain energy rate of element mode) are constructed, then wavelet function is selected to transform the damage parameters, and finally the damage location of the structure is determined. In order to verify the validity of numerical simulation, the dynamic modal test of steel cantilever beam is carried out by means of laboratory instruments, and the actual experimental data are compared with the results of numerical simulation. 2) because the signals collected in the actual detection are often mixed with noise signals, in order to obtain better damage detection signals, In this paper, the method of combining wavelet threshold with MATLAB software is used to simulate the signal de-noising, and the method of de-noising is applied to the experimental acquisition signal to restore the original signal. 3) the damage simulation analysis of the forward quadrangle truss structure is carried out by using the finite element software ANSYS. At first, the optimal excitation position is selected, and the numerical simulation of intact structure and damaged structure is carried out by single point transient excitation. Then the simulation signals are collected, and the strain energy change rate of element mode is taken as the damage parameter. Finally, the damage parameters are transformed by wavelet transform. Then the damage location of the structure is determined.
【学位授予单位】：河北科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TU356
本文编号：2170563
[Abstract]:In recent years, with the rapid development of economy, the construction technology has been improved, and a large number of large-scale and novel long-span spatial structures (such as gymnasium, terminal building, exhibition center, etc.) have been built. Because large span spatial structures are often crowded with people and some places are equipped with important facilities, once the structure is damaged, the damage will cause serious casualties. Large span space structures (such as latticed structures, latticed shell structures, etc.) are subjected to environmental erosion, explosion, earthquake and shock, in addition to being subjected to constant loads such as self-weight for a long time in their design life, resulting in the fatigue accumulation of structural members. The problems of resistance attenuation and material aging make the actual stiffness of the structure degenerate. When the damage accumulates to a certain extent it is possible to cause the overall damage of the structure. Many accidents have occurred in the history of collapse of the long-span space structure. Therefore, in order to prevent the collapse of structures and avoid the occurrence of major safety accidents and economic damage, it is necessary to carry out periodic detection of long-span space structures. In view of the above reasons, the main work of this paper is as follows: 1) the damage analysis of steel cantilever structure is carried out by using finite element software ANSYS. First, the useful information is extracted by transient excitation method, and the damage parameters (strain mode difference of element and strain energy rate of element mode) are constructed, then wavelet function is selected to transform the damage parameters, and finally the damage location of the structure is determined. In order to verify the validity of numerical simulation, the dynamic modal test of steel cantilever beam is carried out by means of laboratory instruments, and the actual experimental data are compared with the results of numerical simulation. 2) because the signals collected in the actual detection are often mixed with noise signals, in order to obtain better damage detection signals, In this paper, the method of combining wavelet threshold with MATLAB software is used to simulate the signal de-noising, and the method of de-noising is applied to the experimental acquisition signal to restore the original signal. 3) the damage simulation analysis of the forward quadrangle truss structure is carried out by using the finite element software ANSYS. At first, the optimal excitation position is selected, and the numerical simulation of intact structure and damaged structure is carried out by single point transient excitation. Then the simulation signals are collected, and the strain energy change rate of element mode is taken as the damage parameter. Finally, the damage parameters are transformed by wavelet transform. Then the damage location of the structure is determined.
【学位授予单位】：河北科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TU356
【引证文献】
相关硕士学位论文 前2条
1 邵长海;基于小波包能量—神经网络的四角锥网架损伤检测方法研究[D];河北科技大学;2012年
2 李超;网架结构焊接空心球节点损伤检测研究[D];河北科技大学;2012年
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