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General Syntax

The "User Model Input File" defines all model components of the MEMS devices to be analyzed. In particular, it defines the solid model elements consisting of mass bodies with perforations and stopper elements, anchors, suspension springs, comb cells and plate capacitors. Additional commands are used to assign material properties and master node locations. These commands are referred to as “pre-processing” commands.

Other commands are “solution” and “post-processing” commands.

Solution commands are used to apply loads, displacement constraints, simulation settings and finally to execute the simulation run.

“Post-processing” commands are used to list, plot and evaluate simulation results.

Both, “solution” commands and “post-processing” commands can either be entered on the command line of the Graphical User Interface or the commands are added to "Load Case Files" which can be loaded in the Assign Loads and Constraints window.

Model file commands are defined in a text file with the following syntax:

  • Each command consists of a “command name”, is followed by several “parameters” and ends with a semicolon.
  • A “comment” starts with a %-sign and can be written after the commands or in separate lines.
  • Parameters can be defined by mathematical terms using the MATLAB-syntax (e.g. cos(x)).
% Mass body dimensions
PARA,body_x   = 90;                     % Length parameter
PARA,anchor_s = 28;                     % Anchor size

% Create anchors
RECT,,add,0,1,,+body_x/2,+body_x/2-anchor_s,-anchor_s/2,anchor_s/2;
RECT,,add,0,1,,-body_x/2,-body_x/2+anchor_s,-anchor_s/2,anchor_s/2;