Feedback for Free Body Diagrams

FBD Feedback Structure

FBD Generic Validation Feedback

Helper functions and feedback for specific objects

These functions are defined in fb_fbd.mac. To use them, include the macro file in the question variables

stack_include("https://raw.githubusercontent.com/mkraska/meclib/main/Maxima/fb_fbd.mac");

• angle() angle between two directional objects

• direction() Identify the direction of objects, e.g. for parallelity check

• moment_of_force() Moment of a "force" object about a given point

• parallelp() Check if two directional objects are parallel

• fb_reactions() Check the number of reaction forces and reaction moments.

• fb_system() Check of activation/deactivation of elements.

• MatchByParallel() Reduce reactions in names to those who are parallel to the support

• Feedback for "fix1"

• Feedback for "fix12"

• Feedback for "fix123"

• Feedback for "fix13"

• Feedback for unidirectional supports, fb_bar, fb_bar_name

• Feedback for line loads

Duplicate Names

This is a temporary state of a function which finds duplicate names,

• names contents of the input field
• res list of reserved names (perhaps used for external loads)
• user list of indices of supports (where reactions can appear)

fb_duplicates(%_names, %_res, %_user):=block( 
  [%_loi: [], %_unames, %_tmp: [], %_dup: [], %_i, %_n],
  /* user supplied names */
  for %_i in %_user do (
    if listp(%_names[%_i]) then %_loi: append(%_loi, %_names[%_i])
  ),
  return([%_loi, true]),
  %_unames: map(lambda([%_i], names[%_i]), %_loi),
  /* check for duplicates */
  for %_n in %_unames do (
    if member(%_n,%_tmp) 
      then %_dup: append(%_dup, [%_n]) 
      else %_tmp: append(%_tmp, [%_n])
  ),
  if not emptyp(%_dup) then return([castext("Der Name \\({@%_dup[1]@}\\) tritt mehrfach auf."), false]),
  ["", true]
);

Attached Forces and Moments

if a de-activated element has active forces or moments nearby, a list of indices is returned in the names list