Explicit dynamics - water tank sloshing due to earthquake

harsfharsf Member Posts: 14
edited December 2020 in Explicit Dynamics

figures consist of a rectangular tank consisting of water, and acceleration vs time data

I have earthquake load as acceleration vs time data. I need to give acceleration to the bottom face of the tank only. But It is not possible in explicit dynamics since it can only be given to "All Bodies" as you can see in the figure.

  1. Does anybody know how to give acceleration vs time data to the tank base in explicit dynamics? or
  2. Since providing displacement to the tank bottom face in explicit dynamics is possible, (for acceleration only "all bodies" is possible) does anyone can convert the acceleration vs time data, to displacement vs time data and send me or/ and if possible include the MATLAB is used send the code too? (excel is not attached as attachments are not possible here)

Best Answers

  • peteroznewmanpeteroznewman Posts: 11,380Member
    edited December 2020 Accepted Answer


    Attached is a zip file of the NS acceleration data double integrated to displacement in mm.

  • peteroznewmanpeteroznewman Posts: 11,380Member
    Accepted Answer


    The displacement at T = 0 must be 0.

  • peteroznewmanpeteroznewman Posts: 11,380Member
    Accepted Answer


    Analog signals exhibit offset and drift, which must be corrected in the data.

    Offsets are corrected by subtracting the mean from the data.

    Drifts are corrected by subtracting the least squares line from the data.

    You can do nothing, offset, drift or both before each integration.

    There are two integrations, so there are 8 choices, and then you can make four more choices after the second integration.

    That is what the vibrationdata GUI makes easy to try out different combinations to get the best result, which is generally that the displacement at the beginning and end of the seismic event is zero.

    I did that, but I forgot to type a zero in for the displacement at T=0 in the zip file I gave you. I forgot that Explicit Dynamics chokes on a non-zero value. A different strategy is to use the velocity data as the input to the simulation, because you are allowed to have a nonzero velocity at T=0.


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