ACS SASSI Documentation

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====== *.cdb Modeling Restrictions ======

The ACS-SASSI interface with the [[ :legal|ANSYS ]](r) Workbench(tm) uses a small subset of elements available to the user of the Workbench(tm) software. The ANSYS(r) file converter will take a Model in the .cdb file format and converts the data to a model that is usable by the [[ SASSI:ACS-SASSI User Interface ]]. The converter only converts a small subset of ANSYS(r) elements and the way that these elements are converted does not cover the full spectrum of how these elements may be defined by ANSYS(r). The limitations below are for models that can be converted to run under SASSI. If a particular option is not discussed it is not supported and will be ignored by the converter.  Any variance from these instructions will either cause an error in conversion or yield an incorrect model when conversion is complete.    

===== Limitations for models that are usable by HOUSE and ANALYS =====


Material Data must be defined using the MPDATA command unless otherwise specified. Any other way of defining or redefining this data is not recognized by the converter.  

Reference to Section Commands in the limitations for the elements implies some combination of SECTYPE, SECBLOCK and SECDATA. Any other use of the section commands in the ANSYS(r) model will not be transfered in the converted SASSI model.

==== BEAM4/BEAM44 ====

BEAM4/BEAM44 elements are convertible with the following limitations. These beam must be defined with the k node definition. These beam must have properties defined by the RBLOCK and the RBLOCK  entry for the property must have either  6, 8, 10, 12 or 19-24 fields defined in the RBLOCK for this element to be converted properly. End releases are defined by KEYOPT 7 and 8. 

==== COMBIN14 ====
COMBIN14 elements are convertible with the following limitations.  KEYOPT 2 or KEYOPT 3 must be defined for the group. KEYOPT 2 will take precedence if both KEYOPT 2 and KEYOPT 3 are defined. The Spring constant must be defined by the by RBLOCK entry. KEYOPT 2 options 1-6 are supported  and options 1 and 2  for  KEYOPT 3.

==== MASS21 ====
MASS21 elements are convertible with the following limitations. Mass data must be defined in the RBLOCK entry. KEYOPT(1) and KEYOPT(2) must be set to 0 or not defined in the .cdb for the mass group to be converted properly. 

==== SOLID45 ====
SOLID45 is convertible. 

==== SHELL63 ====
SHELL63 is convertible with the following limitations. Shell thickness must be defined by RBLOCK entry.

==== SHELL181/SHELL281 ====
SHELL181/SHELL281 is convertible with the following limitations. Shell thickness must be defined using section commands.  SHELL281 will be represented as an equivalent 3 or 4 node shell.  Section Offset must be default or not specified (MID is default for Shells).

==== SOLID185/SOLID186 ====
SOLID185/SOLID186  is convertible with the following limitations. KEYOPT4 which sets the option for nonuniform materials is not defined or set to 0. SOLID186 will be converted into an equivalent 8 node brick

==== BEAM188/BEAM189 & PIPE288/PIPE289 ====
BEAM188/BEAM189 & PIPE288/PIPE289 are convertible with the following limitations. Pipes are converted to equivalent beams for simulation. These elements must be defined with a K node definition. End Releases for these elements cannot be defined for these beams because ANSYS(r) ENDRELEASE command creates new nodes and couples these node to simulate an end release. This cannot be properly represented in SASSI. The beam properties must be defined by using the section commands. Beams must be defined with the ASEC or RECT type option to be convertible. Section Offset must be default or not specified for beams (CENT is default for beam) and must not be specified for pipes.  

===== Conversion for models that use the direct matrix simulation method=====

Newer versions of the fast solver have the ability to take matrices directly from ANSYS(r) and use them in simulation (Option AA). This converter will convert the model that can be displayed in the ACS-SASSI User Interface, but these model will be flagged User Interface and the files that the [[com:AFWRITE]] generates will not be runnable using the traditional methodology. If the model isn't runnable the user will receive a warning when the file is converted. The list of elements types below are the additional element types that can be converted for a display model. There are no limitations on these elements because only element node connections need to be translated for display. Other elements will be ignored by the converter and not be included in the model. The list below specifies the element type from ANSYS(r) and the element type used to represent it in the SASSI model 

====List of elements types & representation in SASSI ====

  * TRUSS180 will be displayed as a beam
  * MPC184 will be displayed as a spring 
  * PIPE16 will be displayed as a beam
  * PIPE18 will be displayed as a beam
  * FLUID80 will be displayed as a solid
  * MATRIX27 will be displayed as a general
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