fb_bar - mkraska/meclib GitHub Wiki

[txt, isOK]: fb_bar(o, n, i, flags)

  • txt feedback text
  • isOK flag for test result
  • o list of objects
  • n names field
  • i index of bar object
  • flags optional string with further instructions
    • T means accept tensile forces only.
    • 2 means test for antiparallel forces close to both ends.

Source

This function provides feedback on "force" reactions replacing a "bar" object in the framework of Feedback for Free Body Diagrams.

Checks done by the fb_bar():

  • Is the object deactivated?
  • Any forces with matching name?
  • For one-sided cut:
    • force parallel to bar?
    • if check for tensile/compressive definition, then check this.
  • For double-sided cut (as might be required in trusswork, not yet implemented):
    • forces of identical name?
    • forces parallel to bar?
    • forces antiparallel?
    • if check for tensile/compressive definition, then check this.

Typical PRT

Feedback variables:

obj: stackjson_parse(objects);
[text, isOK]: fb_bar(obj, names, i1, "T");
[ntext,nOK]: fb_bar_name(obj, names, i1);

PRT node

Node 1: Algebraic test for isOK = true and feedback of {@text@} for both branches. Node 2: Algebraic test for nOK = true and feedback of {@ntext@} for both branches.