Application Of Periodic Structure In Wave Barriers

Periodic structures specially designed were found to enjoy the frequency gap within which the propagation of vibration is forbidden. Many important progresses in formation mechanism and calculation methods have been achieved in last decade. The characteristics of vibration propagation in periodic structures provide a new way to control the vibration in engineering field. As one of effective countermeasures to isolate vibration, wave barriers such as open and in-filled trenches or screens of piles are also intended to impede the transmission of vibrations in the soil. Combining the characteristics of vibration propagation of two, the calculation methods and theory of band gap in periodic structures are introduced to wave barriers with peroidity in this thesis. It can not only predict the frequency gap of wave barriers, but also design the band gap in order to gain a better vibration-isolation result. This thesis carries out a numerical analysis on wave barriers with peroidity. The contents include:1. The vibration band gaps of wave barriers with peroidity consisting of different pattern and piles of various shapes are studied numerically by using improved plane wave expansion method (IPWE). Different physical and geometrical parameters such as density, elastic modulus, filling fraction also have been investigated.2. The vibration band gaps of the two-dimensional three-component periodic structure are calculated by using the finite difference method (FDTD).At the same time, compare and contrast the convergence of the conventional plane expansion method (CPWE), IPWE method and FDTD method.3. Using ANSYS, the screening effectiveness of the two-dimensional continuous barrier with periodity is numerically studied and prove the feasibility of vibration reduction due to the two-dimensional continuous barrier with periodity.