基于改进曲率法和数据融合的结构损伤识别研究

发布时间：2018-07-28 20:48

【摘要】：建筑的服役期往往长达几十年,甚至存在百年以上的大型复杂工程结构,比如超高层建筑、大型水利工程、超大空间结构等等。它们的安全为国民经济和社会环境提供着强有力的保障,然而外部因素和结构内部因素常常导致结构的损伤累积及抗力衰减,因而极有可能在极端情况下引起灾难性的突发事故,造成人员的伤亡、财物的损失。建筑结构的内在损伤一般是不可见的,为了了解结构的健康状况,保证结构的正常使用,必须要对结构进行损伤识别研究,确定结构损伤的位置、甚至损伤程度,才能为结构后期的安全使用提供科学依据。本文以广泛使用的简支梁结构和层剪切型框架结构为研究对象,基于改进曲率法和数据融合方法研究结构的损伤状况,提出了判别结构损伤更为准确的识别方法。主要研究内容包括： (1)针对现有曲率法不能够识别结构首尾单元损伤的缺陷,提出改进曲率法,并在数值模拟的简支梁结构和剪切型框架结构的不同损伤工况下进行验证,结构损伤识别结果表明,改进曲率法能够较准确地识别出结构首尾单元的损伤； (2)研究了静态位移差曲率、模态振型曲率差、模态柔度差曲率以及这三种结构损伤指标的数据融合对简支梁和框架结构的损伤识别的敏感性,数值模拟结果表明损伤指标静态位移差曲率、模态振型曲率差、模态柔度差曲率、数据融合能够有效识别结构的损伤,具有一定的敏感性,且经数据融合后敏感性更高； (3)在利用静态位移差曲率、模态振型曲率差、模态柔度差曲率三种曲率对结构的损伤进行识别时,损伤单元相邻两个单元的曲率明显突出,会引起结构损伤的误判； (4)利用静态位移差曲率对简支梁和框架结构进行损伤识别研究时,在单损伤、双损伤和多损伤工况下均能够有效识别出结构的损伤位置； (5)将简支梁和框架结构的静态位移差曲率,模态振型曲率差和模态柔度差曲率三种损伤指标进行融合,然后对结构的损伤进行识别,经数据融合后的损伤指标能够突出损伤单元的曲率,降低非损伤单元的干扰； (6)研究了简支梁结构和框架结构单损伤工况的损伤程度识别,结果表明改进曲率法和数据融合方法可识别结构损伤程度,且经三次曲线拟合后能够更精确的识别结构的损伤程度。
[Abstract]:The service period of buildings is often for several decades, even more than a hundred years of large-scale complex engineering structures, such as super high-rise buildings, large water conservancy projects, super-large space structure and so on. Their safety provides a strong guarantee for the national economy and the social environment. However, external and structural internal factors often lead to the accumulation of structural damage and the attenuation of resistance. Therefore, it is very possible to cause catastrophic accidents in extreme circumstances, resulting in casualties and property losses. The internal damage of the building structure is generally invisible. In order to understand the health of the structure and ensure the normal use of the structure, it is necessary to identify the damage of the structure, determine the location of the damage, and even the degree of damage. Only then can provide the scientific basis for the safe use of the structure in the later stage. In this paper, the widely used simply supported beam structure and story shear frame structure are taken as the research objects. Based on the improved curvature method and the data fusion method to study the damage of the structure, a more accurate method to identify the damage of the structure is proposed. The main research contents are as follows: (1) an improved curvature method is proposed to solve the defect that the existing curvature method can not identify the damage of the front and tail elements of the structure. The results of structural damage identification show that the improved curvature method can accurately identify the damage of the first and the tail elements of the structure under the different damage conditions of the simply supported beam structure and the shear frame structure. (2) the sensitivity of static displacement difference curvature, modal mode curvature difference, modal flexibility difference curvature and data fusion of these three structural damage indexes to the damage identification of simply supported beam and frame structure is studied. The numerical simulation results show that the static displacement difference curvature, modal mode curvature difference, modal flexibility difference curvature, data fusion can effectively identify the damage of the structure, and the data fusion has a certain sensitivity, and after data fusion, the sensitivity is higher. (3) the curvature of two adjacent elements of the damage element is obviously prominent when the curvature of static displacement difference curvature, modal mode curvature difference and modal flexibility difference curvature are used to identify the damage of the structure, which will lead to the misjudgment of structural damage. (4) when the static displacement difference curvature is used to identify the damage of simply supported beam and frame structure, the damage location of the structure can be effectively identified under the condition of single damage, double damage and multiple damage. (5) the static displacement difference curvature, modal mode curvature difference and modal flexibility difference curvature of simply supported beam and frame structure are fused, and then the damage of the structure is identified. The damage index after data fusion can highlight the curvature of the damage element and reduce the interference of the non-damage element. (6) the damage degree identification of simple beam structure and frame structure under single damage condition is studied. The results show that the improved curvature method and data fusion method can identify the damage degree of the structure, and the damage degree of the structure can be identified more accurately by cubic curve fitting.
【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU317

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