fb_bar

[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.