fb_system() - mkraska/meclib GitHub Wiki

`[txt, OK]: fb_system(names, sys, emv, hint)`

names list from the names input field
sys list of indices of elements which belong to the system (to be active)
env list of indices of elements which belong to the environment and have to be deactivated and replaced by reactions
hint text, problem-specific hint if the system boundaries aren't correct.

Templates

Question text

[feedback:System](/mkraska/meclib/wiki/feedback:System)

Feedback variables

obj: stackjson_parse(objects);
[txt, OK]: fb_reactions(obj, 3, 1);

Feedback:

Field	Value
sans	OK
tans	true
feedback true	{@txt@}
feedback false	{@txt@}

Activation/Deactivation

names[n]="show" is true if element with index n is activated and false if not.

This can be used to check if all supports or distributed loads are de-activated.

The following snippet from the Feedback variables sets OK to true if the object with number i_beam are activated and the objects i_S1, i_S2 and i_S3 are not.

i_beam: 2; i_S1: 5; i_S2: 6; i_S3: 7; 
OK: is(
  names[i_S1]   # "show" and 
  names[i_S2]   # "show" and 
  names[i_S3]   # "show" and 
  names[i_beam] = "show");
txt: if OK then "&nbsp;Die Systemgrenzen stimmen." 
  else "&nbsp;Die Systemgrenzen stimmen nicht. Nur der Balken gehört zum System. Mindestens die Stäbe müssen entfernt (deaktiviert) werden.";

Use AlgEquiv question test with OK as sans and true as tans.

In both branches, say

{@txt@}