Damage Simulation Overhead Crane Girder And Recognition

The nature of bridge crane makes it belongs to more dangerous mechanicalequipments. Moreover it belongs to the special equipment and the nationalinspection department has issued a series of regulatory document and technicalstandards for the safety of special equipment. So keeping the health and safestate of bridge crane in the working process is very important, which requiresthe crane maintenance personnel can more easily understand the healthcondition of the bridge crane, especially the health information of bridgemachine frame girder. Under normal circumstances, with artificial experience tojudge the damage of the main beam does not have a comprehensive andauthoritative, meanwhile the accumulation and inheritance of the experience isalso a difficult problem. However, it requires a lot of manpower and financialresources for using high-tech detection equipment and health online diagnosticsystem. Besides, promotion the use of this tool is not economical. Therefore, thepurpose of this paper is based on the existing theory of the damage identification,combined with the kinetic parameters before and after damage resulting changesin the main beam, looking for a way to effectively identify the damage state.Firstly, the basic size determination of beam section should be made byconventional design, through which to draw two-dimensional map and3Dmodel of the beam with two-dimensional software AutoCAD and3D softwarePro/E respectively.Referring to the3D model diagram of the beam, building thebeam finite element modeling with APDL language in the ANSYS, meshing, etc.Analyzing the static load to get the stress contours and deformation map of thebeam; using subspace method to do the main beam modal analysis, observingthe first few vibration modes of the beam and extracting each order frequencyvalue. Secondly, using“life and death”technology to simulate the beam damage,and designing elements that in different regions of damage cases respectively.Then kinetic parameters are obtained under different conditions of the mainbeam by modal analysis, and the kinetic parameters that before and after thedamage are seen the raw data in the injury analysis. Using several conventional analysis methods to analyze the different kinetic parameters before and afterinjury, but, it can not determine the location and extent of damage injuryaccurately. Finally, combining with the theory of wavelet analysis and neuralnetwork knowledge, using the toolbox of MATLAB software to analyze thekinetic parameters before and after damage, damage can be better judged, andthe damage effect is better identified.Therefore, the main work of this thesis is to simulate the beam injury byusing the unit "life and death" technique that based on the finite element model,and the kinetic parameters of different damage conditions can be obtainedthrough modal analysis, then finding the method of damage identification fromthe changes of perspective of kinetic parameters. In the actual application, thefound damage identification methods combined with equipment measuredkinetic parameters is hoped, in order to determine the beam damage informationeffectively, and provide security for the bridge crane to better service.