I am doing nonlinear time history analysis on a RCC structure resting on soil (3D). I have assumed depth of soil to be 2.5 times the width of the structure. I want to know the correct boundary condition for this analysis.
Hi
Maybe you want to take a look at this discussion?
https://www.researchgate.net/post/How_can_i_define_Absorbing_boundary_in_ABAQUS_EXPLICIT
Sincerely
Claes
Normally, soil side boundaries are taken 2.5 times the width of the base of structure on either side. The depth of soil is taken greater of the two, (i) 1.5 times the width of the base of the structure or (ii) height of the structure. In the wave propagation problem these artificial boundaries should be either viscous boundaries or trasmitting boundaries so that outgoing are either absorbed or trasmitted at the artificial boundaries..
Time history in the form of acceleration time history is applied at the base of the soil boundary. The control motion at the surface has to be deconvoluted and the deconvoluted motion is applied at the base.
2.5 times the base width is more. More depth will take more solution time. 1.5 times the base width will be more appropriate.
Thanks Claes, It will definitely help me.
Thank you sir for your suggestions. I will try as u directed. Will let you know if any further problem arrives.
Dear Sourav Basak, u may refer to this discussion
https://www.researchgate.net/post/is_it_possible_to_import_time_history_functions_from_file_as_load_function_to_abaqus?
Im currently doing my research same field as yours, If you have any idea regarding on boundary condition for acceleration load/time history analysis, please let me know. Thank you.
Hi
As a comment. When estimating fluid loading on vibrating bodies in acoustics, the rule of thumb is to incorporate 1/6th of the wavelength to the model, i.e. a number that varies with frequency, and for soils, with wave type.
The 1/6th of the wavelength rule of thumb is found also for simpler cases like structure vibration of beams where the difference in classical boundary conditions can be seen to incorporate this distance.
As it seems you are looking at nuclear application, perhaps you want to take a look also at Code Aster from EDF. This code is used and developed specifically for the purpose you are seeking and does have some other very useful add ons that you do not find in oher codes. http://www.code-aster.org/V2/spip.php?rubrique2
Sincerely
Claes.
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