Research On Frame Structural Damage Identification Based On The Combination Of Statistics Moment And Generalized Pattern Search Algorithm

With the vigorous advancement of urbanization in China,various building structures have emerged one after another,bringing great convenience to life.At the same time,duo to the long-term effects of various natural and man-made factors on the structure,the damage has been continuously accumulated which has frequently caused various engineering accidents with immeasurable losses.Therefore,in order to meet the needs of the era of the popularization of structural health testing,and to prevent problems before they occur,rapid damage detection for various structures is a very important subject.Based on the team’s research on the use of the statistical moments as damage index,this paper proposes a "two-step method" which combines model-free methods and generalized pattern search algorithm for the frame structures to identify damage locations and damage degree.The main contents and conclusion are as follows:Firstly,based on the statistical moment theory under the single-degree-of-freedom system,the expression of the statistical moment under the multiple-degree-of-freedom system is further derived.Acrroding to the above-mentioned statistical moment theory,the principle of the model-free method using the change of the statistical moment as an indicator is expounded,and the method is further optimized to make it more widely applicable.Secondly,a generalized pattern search algorithm based on statistical moment theory is proposed,and the applicability of the algorithm in identifying frame structure damage is proved through comparisons of different statistical moment indicators and different signal-to-noise ratio conditions.Then,using its characteristics of accurately identifying the degree of damage,combined with the advantages of the model-free method to quickly detect the damage location,a new "two-step method" for structural damage detection is proposed.Thirdly,the "two-step method" proposed in this paper is applied to the damage detection of a 12-storey frame structure,and compared with the two-norm optimization method and the Bayesian thinking method under the same index,and it is verified that the new method has superiority in accuracy,stability and detection time.And further extended to the 21-storey frame shear structure damage detection,the results prove that the "two-step method" still has good applicability.Lastly,based on the data of 12-storey standard frame shaking table test,three typical working conditions are selected for damage diagnosis with the "two-step method".Through test phenomena and comparative analysis with other methods,the results show that this method is more significant than other methods in reflecting the accumulated damage level caused by the working cases,which highlight the reliability of the "twostep method" in engineering detection.