The Simulation Analysis On Damage Identification Of A Simply Supported Beam Bridge

As the vigorous development of highway bridge in our country, the magnitude of the traffic flow has raised as well as the load of highway bridge. Many questions turned up, as the lower traffic capacity and the bearing capacity, the damage of the structure member. How to identify the structural behavior of a bridge has become a question that attracted more and more scholar both at home and abroad. A simulated research on the damage of a bridge structure is explored on foundation of the present research and combined the present questions appeared on the detection of the bridge.Firstly, a finite element model for simply supported steel beam is set up on the basis of the Infinite Element Theory and the software ANSYS in response to laboratory experiment.The natural frequency , frequency domain and the time domain curve etc. of the model beams can be calculated through dynamic analysis of the model beams. And the degree and the location of damage can be identified through inherent frequency and the rate of change of the value of frequency domain. A new method for identifying damages is suggested on the basis of the previous findings in this field to make up for the deficiencies in traditional ways.Introduction to Hilbert-Huang Transform (HHT) is made in this article; index value and the rate of change can be calculated according to the time-displacemnt relation curve simulated through finite element method in the way of combining HHT and the five frequently used Dimensionless parameters(shape factor,peak index,margin index, kurtosis index and impulse index)in traditional time-to-amplitude conversion analysis and adding instantaneous excitation to the mid-span, thus the location and the degree of damage can be efficiently identified. And the location of damage can also be achieved by calculating the peak value of the marginal spectrum, which is available by HHT.However,there are still problems to be solved, such as further researches for proving the HHT priciple and the damage identification of substance beam structure.