摘要
利用双自由度质量-弹簧阻尼模型模拟移动车辆,并基于虚拟变形(VDM)方法的结构快速重分析思想,提出一种车-桥耦合系统的移动质量快速识别的有效方法.该方法以双自由度车体模型的质量为变量,通过最小化桥体结构实测响应和计算响应的平方距离来识别移动质量(载荷),避免了识别载荷时常遇到的病态问题,对噪声鲁棒性强,且需要传感器信息少.每步优化中,利用在VDM方法基础上提出的移动动态影响矩阵概念,无需时时重构车-桥耦合系统的时变系统参数矩阵,显著提高了计算效率.利用数值框架梁模型,通过比较不同车辆简化模型对移动体质量及等效移动载荷的识别效果,验证了该方法的可行性和有效性,即使在5%的噪声影响下,利用一个传感器可以准确地识别多个移动体的质量.
In the inverse analysis of vehicle-bridge coupled system,moving vehicle（load） identification is a crucial problem.Traditionally moving vehicles are identified by identifying the equivalent moving forces,which is a well-known ill-conditioning problem,and hence is sensitive to noise.Moreover identification of moving forces require the number of sensors equal to or bigger than the number of unknown forces to obtain the unique solution.In order to avoid these drawbacks,this paper presents an effective method to identify moving vehicles. Vehicle parameters are chosen as the variables,which are optimized by minimizing the square distance between the measured structural responses and estimated responses.During the optimization,the computational work is reduced a lot by the proposed concepts of dynamic moving influence matrix based on Virtual Distortion Method （VDM）,which consists of impulse response matrix with respect to the changing positions of the moving masses and is independent of mass values,and only needs to be computed once in advance.In this way,the repeatedly construction of the variant system matrix is avoided,and hence the optimization efficiency is improved.In this method,a mass-spring damping model with two degree of freedoms（Dofs） is used to simulate moving vehicle and its dynamic behavior.Moving vehicles and the bridge are analyzed as different substructures.In addition the equivalent moving loads are reconstructed simultaneously,such that the well-conditioning of the identification is ensured and makes the method be accurate and robust to noise.Moreover the number of the necessary sensors is decreased.The numerical costs are considerably reduced further by using the concepts of VDM,which belongs to fast reanalysis method,that is,the response of the modified structure equals to the response of an intact structure subjected to the same external load and to certain virtual distortions which model the changes of the actual structure.In this way,during the optimization,the structural response under given optimization variables are estimated quickly without the whole analysis of the global structure.Numerical experiment of a frame beam with 5%Gaussian measurement error is used to verify the proposed method,where the effectiveness of different simplified vehicle models is compared.It demonstrates that masses of multiple moving vehicles can be identified using fewer sensors.When the roughness of road surface is neglected,under normal speed,the structural response is mainly caused by the weight of vehicles,and the coupling between the vehicle and bridge is rather low,therefore the influence of the vehicle spring stiffness and damping is very weak on the mass identification.For the identification of multiple vehicles,masses of the mass-spring damping model with two Dofs can be identified satisfactorily with the stiffness and damping as the estimated initial values. The identification considering the road roughness or high speed using the proposed method in this paper is undergoing.
出处
《力学学报》
EI
CSCD
北大核心
2011年第3期598-610,共13页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金(50579008)
TEAM项目"Smart&Safe"(TEAM/2008-1/4)
欧洲地区发展基金资助项目(POIG.0101.02-00-013/08-00)~~
关键词
结构健康监测
移动车辆识别
结构重分析
虚拟变形法
影响矩阵
structural health monitoring
moving vehicle identification
structural reanalysis
virtual distortion method
influence matrix
