Check Natural Frequency
Acceleration peak on the slope
The grid is the work area of the numerical model and on it are inserted (by zone or groups of zones) the characteristics seismic-mechanical of the various soil types. Each grid is composed by a series of elements side by side matching in the nodes. The nodes are editable geometrically (with arbitrary distortion of the elements) and in the input information. A regular grid is an easier work plan simple to organize and to edit, but the analysis of irregular model involve a greater focus mainly in the definition of the geometry.
The grid is composed of a number of zones in the direction X and Y and its minimum and maximum size. Importing an Dxf file before generating mesh, the maximum and minimum extension is automatically defined. In this way it's possible to define the physical domain being analyzed and the size of all zones of the model are equal.
Once generated the grid, it is possible to increase or decrease both the number of zones that the number of nodes. Moreover it's possible also change the extension of the grid. The size of the elements is of primary importance in the analysis, the use of excessively coarse elements is a filter of the high frequency components because small wavelengths cannot be adequately modeled.To avoid this, the height of the zones is proportional to the minimum value of the share waves.
It is appropriate to consider square areas, but for particular situations the relationship between the horizontal and vertical dimension of the element (Aspect Ratio) must not exceed three.
A grid assembly is composed of a series of grid blocks side by side to form a macro-grid moldable for simulate various geometries. The individual grid blocks are connected to each other and each one of them can be modified in size and in content of zones.
The position of the vertices or the number of zones of the individual blocks can be changed manually or graphically in order to adapt the grid to the needs of the model to be analyzed. When it's changed the zones number in a block, it's recalculates automatic the continuity of zones in the entire model.