| The global recognition method of the acceleration response sequence after the structure is stimulated as raw data for analysis and processing is not affected by the complexity of the structure,and can be combined with a variety of technologies,which is favored by researchers.Damage identification theories and methods based on structural response are also constantly being updated and improved.When monitoring the actual structure and collecting data,due to the complexity of the environment and the interference of noise,the data collected is usually non-linear.This paper studies the use of acceleration response data after structural damage to identify structural nonlinear damage.Studying nonlinear damage identification is closer to reality,and promotes the practical application of the theory.This article mainly carried out the following aspects of research work:(1)Process the acceleration time series collected when the structure vibrates,analyze the sequence characteristics,select the time series model-GARCH-M model suitable for the model characteristics,and consider the coefficients and properties of the model,put forward the index of damage identification-distance standard deviation index.(2)Proposed the idea of damage identification only through the acceleration time series after damage.The feasibility of this idea has been proved through theory,numerical simulation and experiment.(3)Designed and completed the nonlinear damage identification experiment of the transmission tower model,analyzed and processed the data collected in the experiment,and verified the ideas,models and indicators proposed in this paper.(4)Establish the classic heteroskedastic model GARCH model for the acceleration sequence and compare it with the GARCH-M model.The analysis shows that the GARCH-M model is superior to the GARCH model in terms of goodness of fit,extraction of nonlinear information,and final damage recognition results.Conclusion.Through numerical simulation and experimental research,it is found that the method can accurately identify the location of the damage within a certain degree of damage.The advantage is that it is not necessary to obtain the data before damage when identifying the nonlinear damage of the structure,the calculation is simple,the identification is accurate,and it has good engineering applicability.The innovation of this paper is also the first application of the GARCH-M model in the field of damage identification,and the design and use of a nonlinear simulator in the experimental stage of the transmission tower model. |
