Application Of Strain Mode Difference In The Damaged Beam Damage Detection

This paper reviews based on the theory of structural dynamic characteristics in a variety of modal parameters of the beam-slab structure damage identification methods, emphasizing the application of strain mode difference in damage identification. In accordance with the vibration characteristics, damage identification methods can be divided into five categories: Natural frequency-based methods, Mode shape-based methods, Curvature(Strain) mode shape-based methods, Other methods based on modal parameters and Optimization algorithm-based methods. Their advantages and disadvantages are discussed in this paper, Modal mode shape-based methods and Curvature (Strain) mode shape-based methods are generally focused on the damage location. In order to accurately determine the location of injury, the vibration mode must be optimized algorithms or signal processing, the strain mode under normal circumstances is a very effective damage localization algorithm. Firstly, by several widely used in the modal parameters of the beam-slab structure verified by comparing the effectiveness of the method based on modal parameters, it verified the validity based on the modal parameters. For the beam with certain degree, it is difficult to reflect by displacement modal and natural frequency. The present paper first derives nodal strain modal through its corresponding displacement modal, and then evaluates the strain modal, both prior and post damage, the difference between the strain modal is used as a criterion to assess the damage experienced, based on a simple beam element damage localization method. The formulated method has been demonstrated through ANSYS numerical modeling to be capable of effectively identifying the damage.The following research methods:(1). Research on key technology of direct extraction of strain mode in the damage identification of pure steel structure in the dynamic strain response.(2). The results of simulation experiment. Through the analysis of a number of experimental data, the study of pure steel beam structure under different damage conditions of strain modal parameters corresponding to dynamic characteristics such as sensitivity and evolution law.(3). Based on the modal analysis detection technology and testing technology. Research on about mechanism and mutual influence relationship between parametric and structural damage location, damage degree of structural dynamic characteristics in static and dynamic loading condition.(4).By ANSYS finite element simulation of pure steel simply supported beam, the length of the beam is1.9m, the cross-section is b×h=0.1×0.008m2.To obtain the nature frequency of the structure, the displacement model and strain modal parameters, displacement modal and strain modal experiment of actual beam were compared to the simulation from Donghua5922acquisition system.(5).By the analysis of the theoretical and experimental test, Study the general rules of reflecting the dynamic characteristics of the injury of pure steel structure parameters...