Dynamic Characteristics Of Layered Periodic Foundations With Damping

Periodic structures exhibit a unqiue dynamic character, the attenuation zone in which the wave can not propagate, the present thesis proposes a layered periodic isolation foundation which can attenuate the ground motion. In practical engineering, damping is an important motive parameter of a building structure. But there are few studies on the dynamic character of the layered periodic isolation foundation with damping. In this paper, the lumped-mass method has been used to calculate the complex dispersion curve of the periodic structure with damping, the dynamic response of a layered periodic isolation foundation has been simulated by use of the finite element software. The main research contents include:1, The lumped-mass method to calculate the dispersion relationship of periodic structures with damping has been introduced in detail. The complex-damping method and Rayleigh-damping method has been used to calculate the complex dispersion curve of one-dimensional periodic structures with damping.2, The influence of damping on the complex dispersion curve has been analyzed. The maximum attenuation factor in the first attenuation zone changing with the damping has been studied. The results show that damping has contributed to the attenuation of wave and vibrations.3, The energy flow in finite periodic structure with damping has been illustrated by using mass-spring models, and the influence of the filtering effect of periodic structure for elastic wave changing with the damping has been studied. It proves that the damping can attenuate the energy transfer in periodic structures.4, The model has been established to analyze which is a frame structure on the basis of a layered periodic isolation foundation with damping. The dynamic response of the four-layer structures on the basis of different foundations has been investigated with the finite element software. The results show that the isolation performance of periodic isolation foundation with damping is more superior than that in the case without damping.