Inversion Of Prototype Material Parameters Of High Arch Dam Under Excitation Of Discharge

In recent years,with the construction and operation of a large number of high arch dams with high water head and large flow in China,ensuring the long-term safe operation of dams is important for the safety of the entire project.High arch dams are prone to fatigue damage under the action of dynamic loads and uncertain environmental factors during the operation period,and the strong vibration of the fluid-induced structures is often accumulating the damage of arch dams.The physical and mechanical parameters of high arch dam and its foundations are one of the important indicators reflecting the health of their operation,and play an important role in accurately evaluating the overall operation of high arch dam.To this end,take an arch dam as the research object,and the research methods of prototype observation,theoretical analysis and numerical simulation are used to carry out the inversion of prototype material parameters of high arch dam and its foundation.The main contents are as follows:(1)The prototype vibration response of the arch dam is usually shown in the form of nonlinear and low signal-to-noise ratio caused by the noise from unknown external excitations in the prototype vibration test,resulting that it’s difficult to extract the dynamic characteristic parameters from the vibration signal.Therefore,improved variational modal decomposition algorithm based on the signal characteristics is proposed to filter noise.(2)Considering the accuracy problem of vibration modal information extraction caused by parameter uncertainty,a data-driven stochastic subspace identification based on parameter optimization is proposed,and simulation signals are constructed to simulate the vibration response of the arch dam,the sensitivity of parameter optimization is analyzed to the modal parameter identification so as to find a method that is most suitable for revealing the modal order and modal characteristics of the arch dam in working condition.(3)Considering the calculation efficiency and accuracy of the material parameters of high arch dam,a three-dimensional finite element model considering fluid-structure interaction is established based on the material partitions of high arch dam,the sensitivity of different material partitions to the dynamic characteristics of high arch dam is analyzed,and the material partitions that have a greater impact on the dynamic characteristics of high arch dams are determined.Then,the sensitivity of each material partition on the modal parameters of high arch dam is explored deeply,the mechanism of its influence is clarified and the material partitions to be inverted are determined.(4)Aiming at the problem of low calculation efficiency of finite element forward analysis,a polynomial function is proposed based on response surface theory to improve the inversion efficiency,and the Latin hypercube experiment method is used to generate a parameter sample set considering the distribution of sample points,thereby we construct the response surface mathematical proxy model reflecting the nonlinear mapping relationship between material parameters and modal parameters of high arch dams and replace the finite element model.(5)A novel particle swarm optimization(PSO)algorithm based on Beetle Antennae Search(BAS)algorithm is proposed,because many algorithms are ill-posed and unstable in the process of optimizing and solving the inversion of material parameters of high arch dams.The BAS-PSO makes up for the shortcomings of traditional intelligent algorithms,which are easy to be premature and easy to converge locally,and efficiently and accurately solve the material parameters of high arch dams,providing a new idea for the inversion of material parameters of high arch dam.