The design of foundation for vibrating machines requires an accurate prediction of the foundation response. The method of analysis is complex because it involves the dimension and geometry of the machine foundation, the embedment effect, the material and radiation damping of soils, variation of soil properties with depth, and the interaction effect between the foundation and soils.
DynaMat uses a three dimensional hybrid method to estimate the equivalent dynamic stiffness and damping of machine foundations. Multiple soil layers can be specified and considered by the program.
The hybrid method contains finite elements that are employed in the near field in order to obtain a discrete solution. In the far field, a semidiscrete solution is synthesized from modes also calculated by the finite element method. The solutions are matched by applying the stationarity condition of a functional.
The finite element method is particularly attractive when dealing with problems involving complicated geometries and inhomogeneities. Thus it is widely used in soil-structure interaction studies. Finite elements are employed in the near field (neighborhood of the source of excitation or region of interest). However, because of the unboundedness of the soil region, the near field must be defined by introducing an artificial boundary. It is then necessary to apply conditions at this boundary in order to reproduce the effect of the far field (the complementary unbounded region).Ssince the objective in applying these conditions is to allow absortion or transmission of the waves impinging on the artificial boundaries, the conditions are referred to as absorbing or transmitting boundary conditions and the boundaries are known as absorbing or transmitting boundaries.
Input parameters consist of the dynamic properties of the layered soil, geometric configuration of the mat foundation, and definition of frequencies of analysis. The user specify the foundation with either circular or rectangular shape. The program will automatically generate the three dimensional finite element mesh for the analysis.