Structural Damage Identification Based On Improved Residual Force Vector Method

With the progress of science and technology and the development of economy,civil engineering structure and infrastructure are developing towards large-scale and complicated direction.Under the influence of various functions and surrounding environment,damage accumulation is inevitable in the service of long-span Bridges.Once an important part of the structure is damaged,its damage level will rapidly develop,if not found in time will cause a catastrophic tragedy.Therefore,in recent years,the damage identification of structures has been the focus of current scholars.This paper studies the structural damage identification based on the improved residual force vector method.The main contents are as follows:(1)The present research achievements,advantages and disadvantages of damage identification methods based on frequency,mode,curvature,modal strain energy,wavelet analysis and intelligent algorithm are reviewed.(2)Summary of damage identification technology,the traditional residual force vector method is adopted,when damage to units in a certain order modal node residual force vector is small cause unable to identify,but improve the residual force vector method to even damage units in a certain order modal node can also identify,at the same time,considering the influence of the model and measurement noise,the method through the first few order low-order modal can complete damage identification.(3)Introduce the damage check matrix,check the location of the previous step of damage elements,determine the number and position of damage elements,then use the frequency perturbation method to identify the damage degree,can effectively reduce the number of equations in the frequency perturbation calculation of damage degree,reduce the calculation error.(4)Established the finite element model of simply supported beam and truss structure based on ANSYS,extracted the modal parameters,and then imported them into MATLAB to calculate the damage index-residual force change rate.Numerical simulation was carried out on the structure under single damage and multiple damage,the damage unit location andthe damage degree were characterized by the qualitative analysis of histogram,and then the frequency perturbation method was used to calculate the damage degree of the confirmed unit,so as to verify that this method can accurately conduct the quantitative research on the damage location.(5)The damage identification results of beam structure and truss structure show that the improved residual force vector method has certain research significance and provides theoretical reference for engineering application.