Feedback for "fix13"

[txt, isOK]: fb_fix13(o, n, i, description)

• txt feedback text
• isOK correctness flag
• o list of objects
• n names field
• i index of "fix13" object
• description string with Text to identify the object for the user

[txt, isOK]: fb_fix13_name(o, n, i)

• txt feedback text
• isOK correctness flag
• o list of objects
• n names field
• i index of "fix13" object

These functions provide Feedback for Free Body Diagrams.

Source

"fix13" is a sliding (frictionless) support with a single translational degree of freedom. It is to be replaced by a reaction force and a moment.

Checks done by fb_fix13():

• Is the object really of type "fix13" (just for developers)?
• Is the object deactivated?
• Has meclib found any reactions by proximity check?
• Are there exactly two reactions?
• Are one reaction of type "force" and one of type "moment"?
• Is the force perpendicular to the sliding direction?

Checks done by fb_fix13_names():

• Do the names of the reactions match the name of the support point?
• For force reactions
  • Is the name a single character matching the support name
• For moment reactions:
  • Is the base name equal to M?
  • Does the index match the support name?

Example question: FBD Tutorial Parallelführung (I) at abacus.aalto.fi/develop/4.4beta

Typical PRT

Feedback variables:

obj: stackjson_parse(objects);
[text, isOK]: fb_fix13(obj, names, i_fix13, "Parallelführung bei B: ");
[ntext, nOK]: fb_fix13_name(obj, names, i_fix13);

PRT node 1 test for correct direction

Algebraic test for isOK = true and feedback of {@text@} for both branches.

PRT node 2 test for correct name

Algebraic test for nOK = true and feedback of {@ntext@} in the false branch (with penalty of 0.5).