Free Field Element (Infinite Element for Dynamic Analysis)

 

▒ Overview

IMG_C_ICON_DOT.gifFor the seismic analysis, users need to model infinite ground to eliminate the boundary effect caused by reflection wave. Since it is not possible to model infinite ground, users can apply Free Field Element at the boundary.

IMG_C_ICON_DOT.gifFree Field Element enables to apply traction resulted from Free Field Analysis to the ground boundary and then, eliminate reflection wave using absorbent boundary condition.

 

▒ Methodology

 

IMG_C_ICON_DOT.gifSelect free edges in 2D and free faces in 3D to define Free Field Elements

IMG_C_ICON_DOT.gifFree Field : Enable to simulate infinite ground boundary

IMG_C_ICON_DOT.gifAbsorbent Boundary : Enable to eliminate reflection wave at the ground boundary

IMG_C_ICON_DOT.gifWidth Factor (Penalty Parameter) : In order to minimize the size effect of the model, users have to input more than 104, This value will be multiplied by model width (In case of 2D, this is plain strain thickness (unit width).

IMG_C_ICON_DOT.gifDOF (Degree Of Freedom for damping) : Users can select specified DOF for damping effect.

                                                           [Schematic Overview of Free Field Element]                             [Free field effect (O), Absorb reflection (O)]

 

                                                                [Free field effect (X), Absorb reflection (X)]                             [Free field effect (X), Absorb reflection (O)]

     

IMG_C_ICON_DOT.gifVerification Example : Free field element can result in identical behavior with infinite ground model.

 

                                                             [None]                                                                          [Free Field]                                                                            [Ground Acceleration]

[Infinite Ground]

 

[Displacement results for each case]