Damage Probabilistic Diagnosis Approach For Structures Under Ambient Excitation

In the damage identification of the actual structure, the dynamic characteristics of the structure are impacted environmental loads. In particular, the effects of wind and temperature are more significant, which is as moderate damage. But a factor is considered in the large amount of research instead of various environmental loads.Based on the above issues, this article is that wind and temperature effect on structural dynamic characteristics. The analyzing reveal the random character of combination load of wind and temperature, and it is provided to a damage identification method base on probability. Firstly, assuming that loads are stationary binomial processes, combinations of wind and temperature loads are studied. The maximum entropy is used to establish the combinations probabilistic model of wind and temperature loads. On this basis, integration dimension reduction method and C type Gram-Charlier is used to establish the probabilistic model of structural response by the effect of wind and temperature loads. Base on hypothesis testing, it determine whether the structure occur damage. Then according to damage probability establish damage comprehensive index, it is used to judge location and estimate extent of damage.Numerical examples and test results show Damage identification method based on probability with5%damage is capable of accurate identifying damage, and it is calculated to the probability of damage occurring. The threshold is used to judge the probability of damage when reference state and injury state have overlap region. In three typical environment incentives, Damage identification method based on probability can identify minor damage, especially when the small damage is flooded under lowest temperature and strong wind, but damage identification method based on probability can achieve the desired accuracy. In the case of damage of a plurality of positions of structure, the damage comprehensive index base on damage probability can judge location of damage and estimate extent of damage.