A Study On The Method Of The Damage Identification About Bar-line Structure

The existing of structural damage generates physical property changes of structure,these changes directly reflect on the changing of structure physical parameters,such as rigidity, quality and structure damping.Furthermore the changing of structure physical parameters leads to corresponding changes of structural dynamic property, which reflect on the transformation of structural modal parameter, such as natural frequency of vibration and vibrate modality. Actually, the test of structural power damage is the structural parameter metabolic detection.This paper defines a type of combination indices which is the ratio variance between strain modality and free running frequency's square, these indices are based on strain modality and natural frequency. This research analyzes two identifying methods which are frequency change ratio and combination indices.Based on this analysis,this research numerical simulates truss structure and frame structure damages separately, utilize these two identifying methods to implement damage identification study on structure.This paper mainly focuses on:(1)The current research trends of the research topic, study on the methods for structure damage detection which are based on kinetic parameter.(2)Elaborating the identifying methods which are developed by frequency change ratio, combination indices.(3)Through the application of finite element software ANSYS to analyze truss structure and frame structure, front-five exponent modality both in whole and damaged status, generate front-five modal parameter of the structure.(4)Utilize frequency change ratio and combination indices to implement damage identfic- ation on truss structure and frame structure,includes:the sensitivity analysis of front-five expon- ent modality,the damage identification on different places and the extent of damage relativity.(5)According to above theories and numerical analysis,this research analyzes the charact- eristics, biases, maneuverability and applicability of two types of damage identification parame- er which are based on frequency change ratio and combination indices, assesses these methods and perfects these assessments in a certain extent,as well as proposes some suggestions for the application of these identification methods on practices.