The Damage Idoitification Study Of Steel Truss Structure Based On Fequence Response Function

All kinds of civil engineering structure will suffer from man-made destruction and theenvironmental effects of erosion, and the effect of natural disasters during the long-term use,all the effect factors will influence the use of civil engineering structures, therefore, in order toensure the safety, economy and durability of the structure, we can use some methods to detectthe structural damage,and maintenance or repair in time, in this way we can not only increasethe used life of the structure, also avoided the economic and security disaster caused bystructural damage.We needs an effective and reliable method to identificate the damage of structure,because the dynamic performance of the structure and its physical parameters closely linkedunder the effect of incentive, so if the physical parameters changed, namely the structuredamage, they will be reflected in the structure’s dynamic characteristics, we can recognize thedamage location and damage degree of structure and provide clear guidance for maintenanceand repair through the research on dynamic characteristics of the structure.The main contents of This paper: to summarize the research status of structural damageIn the domestic and overseas, as well as the theory basis of the damage identification.Tostudy a spring-mass system to test and verify the reliability of the selected damageidentification index, and provide the basis of the parameter that we need when donging thenumerical simulation analysis for truss structure and model dynamic test analysis.Across the object of this study is cantilevered truss structure of6and10across, membersof truss structure is too much, in order to get more accurate detection, we has used Ansys tosimulate the damage condition which includes single damage, multiple site damage and theposition of damage bar by using three damage indexes are curvature, curvature ratio andcurvature difference of the FRF(Frequence Response Function).and calculate the damageindicator under different damage degree.according to the numerical simulation analysis: theabove three kinds of damage indexes can detect the structural damage location and damage degree for truss structure, but the accuracy of the frequency response function curvature ratiois best, it can not only detect structural damage location and damage degree, And canaccording to it to get accurate detection that which membes is damaged., the other damageindexes are influenced by the support form,the farther from the support the less senstive.butthe FRF curvature ratio impregnable of support form and detect the damage of the structureaccurately.Made cantilevered truss structure model of6across, identify the damage of thestructure use the Vibration and dynamic signal collection, the condition of the damage onlyconsider simply, through dynamic model test of model structure, to verify the effectivenessand the accuracy of the damage identification index.