| High speed flow carrying huge energy impacted the flood discharge structure causing strong vibrations of building to fatigue damage, which was a serious threat to the safety performance of the project. Flow-induced structural damage was mainly due to the displacement or dynamic stress caused by vibrations exceeding the safety standards. Therefore, it was not only to master the generationg mechanism of flow-induced vibration but also to get the overall vibration response of the structure to evaluate the safety of buildings.With complex environment, it only got the vibration response of a finite number of measuring points upon water structure. It was difficult to measure the vibration response of the underwater part's. The overall vibration characteristics of structure were sloved according to a finite number of measuring points response information in vibration prototype observation for the safety evaluation of structure, which had important engineering significance. This paper carried out the following work.(1) Numerical simulation of the flow-induced vibration of back analysis based on particle swarm optimization algorithm.The dimensional finite element model of guide wall was established, which was applied typical load to extract dynamic displacement of corresponding measuring points as the calculated value. Based on the back analysis theory, the hydrodynamic loads were solved optimizing the load results with the particle swarm algorithm. According to the inverse load the vibration response mean square value of guide wall was analyzed.The retrieval viaration response value was comparied with the calculated value. The comparative results showed that the error of the displacement inverse value and calculated value of guide wall corresponding measuring points were less than 5%, which verified the feasibility of structural vibration back analysis. The load inversion error of particle swarm algorithm was 1.41% and the least squares' s was 3.15%, which indicated the superiority of particle swarm optimization.(2) The vibration response back analysis of a sluice pier based on field mearsurement. The sluice project was carried out prototype observation extracting dynamic displacement of the measuring point in six typical operating conditions. The dimensional finite element model was established to extract the structural characteristic information and combined with the known displacement form prototype observation, the equivalent load of six kings of working conditions was solved throw back analysis theory. Based on particle swarm optimization the recognition accuracy of vibration source was improved, and based on positive analysis and modal superposition method the overall structural vibration was derivied. The results showed that the structural vibration response calculated values from back analysis had high similarity with the measured values from prototype observation, which illustrated the correctness of back analysis method. Integrated six kinds of conditions, it was got that the variation of structure vibration response(dynamic displacement and dynamic stress) and the maximum value of dynamic displacement and dynamic stress response, which laied the foundation for the safety evaluation of the sluice.(3) The safety evaluation of the sluice vibration. Referencing the safety assessment standards about the blasting vibration, the offshore platforms, tranis and the like, the safety of discharge gate on flow-induced vibration was evaluated from two aspects of the influence on the building stabilizing and the influence on human comfort. The dynamic displacement indicators, dynamic stress index, the two factor criterion of frequency-amplitude were used to evaluate the structural safety. The impact on human body by vibration was evaluated thorw Meister feel curve. The result showed that the sluice was safe under the six kinds of vibration conditions, but it made the body feel strong vibrations and slightly uncomfortable. |
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