基于振动响应的桥梁结构非线性模型检验及参数确定

发布时间：2019-05-19 13:08

【摘要】：桥梁结构中螺栓、间隙、边界等或者结构本身出现损伤都会引起非线性行为,非线性现象在桥梁结构中普遍存在。随着桥梁结构形式向轻柔化发展,非线性效应愈发明显。如何准确模拟分析桥梁结构的非线性行为对于确保桥梁结构的安全性具有重要意义。本文主要研究基于振动响应的桥梁结构非线性模型检验及参数确定,具体的研究工作包括:(1)研究了单自由度结构非线性模型检验及参数确定方法,通过恢复力曲面和支持向量机相结合进行单自由度结构非线性类型识别,进一步采用最小二乘估计法确定结构非线性模型参数。论文首先利用系统的恢复力曲面计算得到非线性指标,并以获得的非线性指标作为训练数据训练支持向量机分类器,利用支持向量机的模式识别功能判断结构非线性类型;由此,可以获得结构非线性模型的函数表达式,进一步利用最小二乘估计法便可确定非线性模型函数的参数。(2)研究了多自由度结构非线性模型检验及参数确定方法,通过分析多自由度结构动力方程,得到单元恢复力与相对位移之间关系,从而对多自由度结构的刚度进行非线性类型识别及参数确定。假定结构阻尼为瑞利阻尼,识别出结构刚度后,进一步可以反算出阻尼系数。论文首先分析了多自由度剪切结构,利用所提的方法,识别了剪切结构的层间非线性类型并确定了其非线性模型参数。然后,论文进一步分析了多自由度梁式结构,考虑了梁式结构的转动自由度效应,利用所提方法,有效的识别了局部单元的非线性类型并确定了非线性模型的参数。(3)最后以一座连续刚构桥为工程背景,采用OpenSees建立有限元模型,考虑桥墩底部局部非线性行为,计算了桥梁结构的振动响应,随后利用提出的方法对该桥进行非线性模型检验及参数确定。论文有效地识别出了非线性单元的位置、局部单元非线性类型,并确定了局部单元非线性模型的参数,验证了方法的有效性。
[Abstract]:The damage of bolt, gap, boundary and so on in bridge structure or the damage of structure itself will cause nonlinear behavior, and nonlinear phenomenon is common in bridge structure. With the development of bridge structure to softness, the nonlinear effect becomes more and more obvious. How to accurately simulate and analyze the nonlinear behavior of bridge structure is of great significance to ensure the safety of bridge structure. In this paper, the nonlinear model test and parameter determination of bridge structure based on vibration response are studied. The specific research work includes: (1) the nonlinear model test and parameter determination method of single-degree-of-freedom structure are studied. The nonlinear type of single-degree-of-freedom structure is identified by combining restoring force surface with support vector machine, and the parameters of structural nonlinear model are determined by least square estimation method. In this paper, the nonlinear index is obtained by using the restoring force surface of the system, and the nonlinear index is used as the training data to train the support vector machine classifier, and the pattern recognition function of support vector machine is used to judge the nonlinear type of the structure. From this, the function expression of the structural nonlinear model can be obtained, and the parameters of the nonlinear model function can be determined by using the least square estimation method. (2) the nonlinear model test and parameter determination method of the multi-degree-of-freedom structure are studied. By analyzing the dynamic equation of multi-degree-of-freedom structure, the relationship between element restoring force and relative displacement is obtained, and the nonlinear type identification and parameter determination of the stiffness of multi-degree-of-freedom structure are carried out. Assuming that the structural damping is Rayleigh damping, the damping coefficient can be calculated inversely after the structural stiffness is identified. In this paper, the multi-degree-of-freedom shear structure is analyzed, and the interlaminar nonlinear types of shear structure are identified and the nonlinear model parameters are determined by using the proposed method. Then, the paper further analyzes the multi-degree-of-freedom beam structure, considers the rotational degree of freedom effect of the beam structure, and uses the proposed method. The nonlinear types of the local element are effectively identified and the parameters of the nonlinear model are determined. (3) finally, taking a continuous rigid frame bridge as the engineering background, the finite element model is established by using OpenSees, and the local nonlinear behavior at the bottom of the pier is considered. The vibration response of the bridge structure is calculated, and then the nonlinear model test and parameter determination of the bridge are carried out by using the proposed method. In this paper, the position of the nonlinear element and the nonlinear type of the local element are identified effectively, and the parameters of the nonlinear model of the local element are determined, which verifies the effectiveness of the method.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441.3

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