Research On Damage Diagnosis Simulation Of Suspension Bridge Based On Static And Dynamic Test Of Model

Bridges are an important lifeblood of economic construction and national development,and an integral part of the transportation system.Their health directly determines whether traffic can operate normally.Compared with other structures,the bridge structure not only bears permanent loads such as self-weight and pre-stressing,but also bears dynamic loads and accidental loads such as crowds,vehicles,and wind that change greatly,so its damage is unavoidable.Damages that are not found in time gradually accumulate,and the deterioration of the initiating structural performance is likely to cause damage to the bridge structure,resulting in catastrophic damage.Therefore,the research of bridge structure damage diagnosis has extremely important theoretical research significance and practical application value.Suspension bridge,as a representative form of modern long-span bridge,has been chosen by many large-scale projects because of its superior load-bearing performance,long span distance,and beautiful structural form.However,there are also shortcomings such as complex structural forms,diverse components,and easy damage due to various factors and various loads.Therefore,damage diagnosis of suspension bridge structures has become a hot topic at home and abroad.In this paper,a 1:100 suspension bridge test model is established for static and dynamic tests.The basic data such as deflection,strain and frequency are determined through the test and compared with the finite element model.The finite element model is corrected to ensure its accuracy,and then corrected by the equivalent strain method.After the finite element model is used to simulate damage,different damage data is collected,and the damage type and degree of damage are analyzed in various ways.The main work is as follows:1.Investigate the data of long-span suspension bridges at home and abroad,and refer to existing bridge test model design experience to design and build a suspension bridge model that can simulate various types of damage.All components are made of steel to meet the requirements of detachable,replaceable components and models that can simulate various Damage conditions,good economics and other conditions,and the model is used as a carrier for damage identification tests.2.Model static and dynamic tests.Design the test model static and dynamic load test plan,install various sensors to collect test data.In the non-destructive state,the main beam constant load test is completed and a finite element model is established for load comparison analysis.Secondly,adjust the model to the unloaded state,damage the main beam and boom to different degrees,repeat the dead load process,observe and analyze the static response of the test model,and complete the static damage diagnosis.3.The application of Winger-Vill(referred to as WVD)cross term in damage identification is proposed.With the help of MATLAB design time-frequency analysis program,ANSYS is used to establish a finite element model of beam structure with cantilever beam and simply supported beam.Load,collect the acceleration data of each measuring point for analysis,and verify that the WVD cross term can identify structural damage.4.Modify the finite element model of the suspension bridge according to the static measured data,and take the finite element model as the research object,design the main beam,main cable,and boom damage conditions,give the model certain excitation,collect acceleration data of each measuring point,and set the threshold Screening the energy distribution of the cross-terms and comparing the amplitudes of the cross-terms in the lossy and non-destructive state of the test model,the results show that the WVD cross-terms can clearly identify the damage location and damage degree of the suspension bridge structure.