3D Design

3D Design

boundary condition with both spatial and temporal variables

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    • masud407
      Subscriber

      I would like to apply force or pressure which is a function of the spatial parameter (theta) and time (t). How can I insert such kind of boundary conditions for transient analysis? I can understand I can insert force either as a function of time or as a function of space. But how can I apply a force which is a function of time and space at the same time? Thanks

    • Bill Bulat
      Ansys Employee

      You'll probably need to create an APDL command object. We call lookup tables such as these "table arrays". You have to define/dimension the array prior to filling it with the *DIM command, e.g.,

      *DIM,array_name,TABLE,m,n,,Y, TIME,,12

      will dimension a table array named array_name having m rows and n columns. Note the "12". This assumes you have defined a cylindrical coordinate system that is manually assigned a coordinate system ID number of 12 (this setting may be established in Mechanical in the Details of the cylindrical coordinate system once you create it).

      So the "Y" is, in a cylindrical coordinate system, actually the theta coordinate in degrees. In my example above, the values going down each column of the planar m X n array will correspond to theta coordinates. Values going across each row correspond to time values. The Y (theta) coordinates for the lookup table are entered in the "zeroeth" column, and the time values are entered in the "zeroeth" row. "Zeroeth"? I know this sounds weird. Please locate and review the section in the MAPDL Help (image below) to try to get an idea what I'm trying to say:

      Kind regards,

      Bill

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