Research On Seismic Motion Input And Numerical Simulationmethod Of Dynamical Artificial Boundary

For the dynamic analysis of some important complex structures such as high-rise,high dam, nuclear power station and so on, the wave propagation from structure into infinite foundation should be considered. The problem is huge for solution, and may include mediums coupling, medium material nonlinearity and dynamic contact interfaces etc. Therefore, an effective numerical method must be provided for thedynamic analysis of this large complex system. The combination method of the explicit finite element method and the local artificial boundary is applicable to solute the above complicated problem because of its uncoupling characteristic. So, The partial artificial boundary research and development has received the from all walks of life attention. This article mainly revolved to viscous spring boundary to do the corresponding research, obtained some to have the reference value the understanding.1. According to the important structural time history analysis, cosine function with evenly distributed random phase angle is chose to synthesize seismic wave as a numerical model. It could not only meet the three factors of seismic wave, but also link up with response spectrum of actual specifications. Corresponding program is programed according to the numerical model presented in this article to realize the simulation of seismic wave.2. By the digital filtering method, the acceleration history of artifical ground motion is obtained, because the remaining long period components, the integrate displacement data by double integral of acceleration history, have great baseline drift from the true one because of the remaining long components. It employs least squares method to programme procedure with high precision which could check time domain of temporal curve of seismic wave.3. With the consideration of the destruction caused by the structure and the liquation inside the foundation generated mainly by shear wave, free space is often simplified as horizontal laminated semi-space model. At the present time, there are a lot of analytic methods of earthquake response of free space, such as the model of lumped mass, theoretical method of one-dimensional fluctuation, the stator elemental method and so on. In this article two methods of lumped mass and one-dimensional fluctuation are utilized to calculate the earthquake response of free space.4. Against the function of non-reflection boundary supplied by the program of LS-DYNA, secondary exploitation is tried to implement viscoelastic and manmade boundary, and precision is certificated through two typical calculating model. Its precision could meet the requirement of engineering calculation,and its low-frequency stability is better than that of multistage transmission boundary.5. The analysis of dynamic earthquake response of arch dam is done through viscoelastic manmade boundary and explicit finite-element methods, which supply a new idea for engineering earthquake-resistance analysis.