Numerical And Experimental Study On Vibration Isolation Measures With Barriers

With the rapid development and urbanization in China, environmental vibrations from production, transportation and construction are becoming more and more serious, which have brought problems to people's life and work. Against this background, it's of great significance to study vibration isolation measurements. Barrier is an effective isolation method which serves by cutting off vibration transmission. It can be used in various conditions and has come to common use.A series of research has been done to study the barrier isolation in this paper. At the beginning, the types and characteristics of vibration waves are discussed based on elastic wave theory, and the isolation mechanism of barrier is explained in further. In the coming, model test is performed to study the propagation and decay of impact-load induced vibration in sandy soil, in which foam barrier is included to analyze isolation effect. Then, the FEM solver LS-DYNA is introduced and its application in simulating soil dynamics is detailed regarding some key points. After that, a simulation of model test is performed and the numerical results agree well with test, which proves that the FEM is accurate and feasible. At last, the justified FEM is utilized to do parametric study on the subject of barrier isolation, mainly considering the vibration frequency, barrier size and material.Theory, model test and numerical simulation are well agreed in parameter calibration and results, the correctness and feasibility of analytical method are fully proved. The results of parametric study show that wave impedance ratio is critical in affecting isolation effect, which could serve as criteria in classifying rigid and soft barrier. When impedance ratio is far beyond or below one good vibration isolation effect can be achieved. The influence of barrier size on isolation effect abides by such a law: the deeper and wider barrier works better, a larger isolation area can be achieved with wider barrier; however, thickness contributes less to isolation effect.