基于应变模态的网壳结构损伤识别研究

发布时间：2018-05-06 16:59

本文选题：网壳结构 + 损伤识别　；参考：《兰州理工大学》2013年硕士论文

【摘要】：随着经济的飞速发展以及科学技术的不断进步,以网壳结构为代表的大跨度空间结构在国内外广泛应用,然而,随着这些大型结构的不断发展,其伴随着的问题也不断凸显。这些大型复杂结构在复杂多变的自然环境中,承受着各种威胁,导致结构可能产生各种不同的损伤情况。这些大跨度结构,如网架、网壳,都关乎着人民的生命和财产安全,及时准确的获得结构的损伤状况、预测结构剩余寿命、为后续加固方案提供重要信息等就具有不同寻常的意义和举足轻重的作用。本文主要阐述了国内外结构损伤识别的研究背景和研究现状,以及基于模态参数的损伤识别理论,重点研究了基于应变模态的损伤识别理论,并将应变模态损伤识别理论运用在网壳结构中。网壳结构是大跨度空间结构中的一种重要的结构形式。本文通过试验模态分析,对有限元模型进行模态修正,将固有频率作为修正参数,使最终修正后的有限元理论模型与试验模型的固有频率高度相似,为后续损伤分析的精确度提供了一定的保障。对修正后的网壳进行损伤识别分析,利用静力分析确定损伤工况,讨论网壳结构在前三阶的不同损伤工况下的损伤指标—应变模态差的不同变化规律,通过大量的分析表明： (1)在单杆损伤情况下,利用损伤指标能够准确快速的识别出受损杆件,并且通过损伤指标的大小关系,可以容易的判别损伤程度。因此,应变模态能够有效识别单杆损伤的损伤状况。 (2)在多杆损伤的情况下,对杆件的损伤识别需要区分杆件的类别,对于同类型杆件,可以一次性识别出损伤杆件,而对于不同类型杆件同时损伤时,需要进行两步识别法,通过同类型杆件损伤指标的比较,对损伤杆件进行有效的识别。分析表明,两步识别法可以有效识别多杆损伤下的受损杆,并且判别出损伤程度。
[Abstract]:With the rapid development of economy and the progress of science and technology, the long-span space structures represented by latticed shell structures are widely used at home and abroad. However, with the continuous development of these large structures, the accompanying problems are constantly highlighted. These large and complex structures are subjected to various threats in the complex and changeable natural environment, which may lead to a variety of damage conditions. These long-span structures, such as latticed structures and latticed shells, are all related to the safety of people's lives and property, timely and accurately obtaining the damage condition of the structure, and predicting the remaining life of the structure. It is of great significance and importance to provide important information for the subsequent reinforcement scheme. In this paper, the research background and present situation of structural damage identification at home and abroad, the damage identification theory based on modal parameters, and the damage identification theory based on strain mode are introduced. Strain mode damage identification theory is applied to reticulated shell structure. Reticulated shell structure is an important structural form in long span spatial structure. In this paper, the modal of the finite element model is modified by the experimental modal analysis, and the natural frequency is taken as the correction parameter, so that the modified finite element theory model is highly similar to the test model. It provides a guarantee for the accuracy of subsequent damage analysis. The damage identification analysis of the modified reticulated shell is carried out, the damage condition is determined by static analysis, and the different variation law of the damage index-strain modal difference of the reticulated shell structure under the first three different damage conditions is discussed. Through a lot of analysis, it is shown that: 1) in the case of single rod damage, the damage index can be used to identify the damaged member accurately and quickly, and the damage degree can be easily judged by the relationship between the damage index and the damage index. Therefore, the strain mode can effectively identify the damage condition of single rod damage. (2) in the case of multi-rod damage, the damage identification of the member needs to distinguish the type of the member. For the same type of member, the damaged member can be identified at one time, but for the different type of member at the same time, the two-step identification method is needed. The damage index of the same type of member is compared to identify the damaged member effectively. The analysis shows that the two-step identification method can effectively identify the damaged rod under multi-bar damage and identify the damage degree.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU33;TU317

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