【作者】 陈长生；

【导师】 王丽娅；

【作者基本信息】 吉林大学 ， 工程力学， 2008， 硕士

【摘要】 随着社会的发展、科技的进步,现代工程结构向着大型化、复杂化的方向发展。大型复杂结构一旦发生事故,所带来的损失和影响都是惊人的,因此对结构的健康状况进行适时的评估变得尤为重要,而损伤识别则是结构健康检测中的一项关键技术。在土木、机械以及航空工程等领域,利用结构动力特性的变化对损伤进行识别,已经成为一个受到广泛关注的研究方向。本文阐述了国内外结构健康监测技术的研究背景、发展现状和损伤理论的应用情况。重点阐述了平面桁架振动特性和基于模态分析的损伤识别理论与数值仿真。桁架结构由于其重量轻,材料使用率高,在大型厂房、桥梁结构中都被广泛应用,对桁结构进行损伤识别具有实用意义,因此,本文用平面悬臂桁架结构作为研究对象,利用局部刚度损坏后固有频率和振型的为参数利用位置向量法对结构进行了识别,得出如下结论:(1)杆件发生相同程度损伤时,结构频率变化率随着杆件离固定铰支座距离的增大而减少;同一杆件发生不同程度损伤时,结构频率变化率随着杆件损伤程度的增加而增大。(2)在计算出相应的固有频率和振型的情况下,运用位置向量方法对结构损伤进行识别,能较好地识别出损伤的位置及损伤程度,且验证了此方法也适用于多个杆件同时发生损伤的情况。通过本文研究,掌握了结构损伤前后频率变化规律以及固有频率和振型参数对局部刚度改变的敏感程度,验证了位置向量法对桁架结构的适用性。更多还原

【Abstract】 With the development of society and the advancement of technology, modern engineering structures toward to the direction of large and complexity. Large and complex structures event of an accident caused by the loss and impact are alarming, so the health status of the structure timely assessment has become particularly important, and injury is to identify the structural health of a key technology. In civil, mechanical and aeronautical engineering, and other fields, the use of structural dynamic change in the characterization of the injury identification, it has become a widespread concern by the research direction.In this paper we described the structural health monitoring at home and abroad technology research background, and the status and development of the application of the theory of injury. We focus on plane truss based on the vibration characteristics and modal analysis of the damage identification theory and numerical simulation. Truss structure because of its light weight, high utilization of materials, in large factories, bridges, structures have been widely used in the truss structure damage identification of practical significance, therefore, this paper plane cantilever truss structure as a research object, use of local stiffness and damaged mode changes (That is, the difference between the vibration mode for the parameters of) on the structure of the recognition, we have reached the following conclusions:(1) Bar in the same degree injury, structural changes in the frequency rate with a fixed hinge rod bearing distance from the increase reduced the same bar when the injury occurred to varying degrees, with the rate of structural change in the frequency of injury at the increase.(2) In the calculation of the bands corresponding vibration mode poor circumstances, the use of vibration to poor identification of parameters of the structural damage identification can be used to identify the location of the injury.This paper studies the grasp of the structural damage before and after change of frequency, confirmed the mode parameter is worse plane cantilever truss damage identification of sensitive parameters.更多还原