Numerical And Experimental Study On Damage Detection Of Beam Under Moving Loads

Structural damage detection is to diagnose and evaluate the state of the structure when the structure is damaged,in order to accurately identify the damage location and damage degree of the structure,and further analyze the causes of the damage.According to the structural damage detection report,the designer evaluates the safety of the structure,and puts forward the best scheme for the maintenance and reinforcement of the building structure.Beam structure is a common structural form in engineering,and is an important part of the main structure.In this paper,the beam is taken as the research object,and the micro damage in the beam structure is simulated by using the spring element without thickness.To explore how to set the relevant parameters of beam element,the numerical model can be more close to the engineering practice.The dynamic characteristics of the damaged beam are obtained by applying the moving load on the beam.The displacement time history curve and acceleration time history curve were obtained by collecting the transient response data.The time history curve data are analyzed and processed to determine the damage location of the beam structure.Based on the study of the related problems of damage detection,this paper studies from the following aspects:Firstly,the dynamic behavior of the damaged beam is studied by establishing the dynamic equation of the beam structure and the vibration analysis of the damaged beam.Based on this theory,a damage model of beam structure under moving loads in ANSYS software,select the spring element simulating tiny damage thickness can be ignored,applying moving load on the beam,the displacement of different damage degree,different load,different moving speeds curve and acceleration curve.Secondly,according to the existing conditions of the laboratory design model test.On the basis of the test beam model,the crack damage of different positions and different degrees is set up,and the different load quality,different moving speed and different measuring points are compared and analyzed.Finally,the method of denoising and wavelet transform is used to deal with the data obtained from the experiment and numerical simulation,and the location of the damage and the influence of various factors on the results are obtained.In the damage detection,the greater the mass of moving load is,the smaller the speed is;the greater the degree of damage is detected;the closer the damage position is to the measured point,the more obvious the detection effect is.For the same working conditions and the same testing conditions,the acceleration time history curve is more effective than the displacement time history curve.The original can not see the curve of the displacement damage,after wavelet transform,the damage position scale is greater than a certain value of light spot becomes more obvious,we choose wavelet transform a scale which can be found obviously raised in the injury,can successfully detect the damage.The study on the damage detection of beam structure under moving load has some reference value for other types of structures.