Study On Damage Identification Method Of Steel Structure Based On Improved HVD

The large derrick steel structure is widely used in all kinds of engineering fields,and usually in a comlex field working environment.In the process of long-term outdoor service,various structures are prone to different degrees of damage,which leads to the decline of its safety.And it is easy to cause a large number of personnel and property losses.Therefore,through studying the response signals of the derrick steel structure under different loads with noise,two methods for damage identification of derrick steel structure are proposed.The first is the damage identification method based on the Hilbert Vibration Decomposition(HVD)marginal spectral entropy relative curvature.The second is the damage identification method based on the Intrinsic Mode Function(IMF)instantaneous amplitude variance curvature.The effectiveness of the new method in damage identification of derrick steel structures is verified by simulation calculation and experimental analysis.Firstly,parameters used in derrick steel structural damage detection were analyzed,and derrick steel structure model were built using the ANSYS parametric programming language.Dynamic characteristic parameters of structure were obtained through the finite element modal analysis,which provides theoretical basis for follow-up signal feature extraction technology.Secondly,according to the relevant concepts and theories of HVD,the causes of endpoint effects during the decomposition of HVD are analyzed.The method of combining support vector machine and analytic modal decomposition is used to improve the problem of HVD end effect.The signal feature extraction method of steel structure of derrick based on improved HVD is adopted.Taking the HVD marginal spectral entropy relative curvature and the IMF instantaneous amplitude variance curvature as damage indicators,the change trends of the two methods under different loads are analyzed.Thirdly,the damage identification of derrick steel structure is simulated and analyzed.Taking the difference of HVD marginal spectral entropy relative curvature,and the difference of curvature of IMF instantaneous amplitude variance before and after the derrick steel structure damage as the damage index.The relationship between the damage index and the damage location,as well as the influence of different damage degrees at the same location are analyzed.The feasibility of identifying the location of different damage elements with two damage indexes is verified by ANSYS finite element model and laboratory damage location simulation experiment.Finally,a derrick steel structure damage identification system based on Lab VIEW and MATLAB is designed.It can realize the function of derrick steel structure vibration signal acquisition,storage,call,processing and structure damage identification,and provide convenience for derrick steel structure damage identification.