Line 1: |
RESTRAINTS |
|
Next n lines: |
Node,Rest,Gr,Gen,Ni,STx,STy,STz,SRx,SRy,SRz,Dirn, Nx,Ny,Nz,Dx,Dy,Dz,Fx,Fy,Fz |
|
|
|
|
Node |
Node number |
(Integer) |
Rest |
Restraint code (F/R/S/V/P/N) |
(6 Char) |
Gr |
General restraint (Y/N) |
(1 Char) |
Gen |
Obsolete (Ignored) |
(Integer) |
Ni |
Obsolete (Ignored) |
(Integer) |
STx |
X translational spring stiffness (if S) or plastic limit (if P) |
(Real) |
STy |
Y translational spring stiffness (if S) or plastic limit (if P) |
(Real) |
STz |
Z translational spring stiffness (if S) or plastic limit (if P) |
(Real) |
SRx |
X rotational spring stiffness (if S) or plastic limit (if P) |
(Real) |
SRy |
Y rotational spring stiffness (if S) or plastic limit (if P) |
(Real) |
SRz |
Z rotational spring stiffness (if S) or plastic limit (if P) |
(Real) |
Dirn |
Direction code (P/N/B) |
(6 Char) |
|
The following items apply only to friction restraints |
|
Nx |
Normal axis for X friction restraint (Y/Z) |
(1 Char) |
Ny |
Normal axis for Y friction restraint (X/Z) |
(1 Char) |
Nz |
Normal axis for Z friction restraint (X/Y) |
(1 Char) |
Dx |
Normal reaction direction for X friction restraint (P/N/E) |
(1 Char) |
Dy |
Normal reaction direction for Y friction restraint (P/N/E) |
(1 Char) |
Dz |
Normal reaction direction for Z friction restraint (P/N/E) |
(1 Char) |
Fx |
X friction restraint reaction limit as proportion of normal reaction |
(Real) |
Fy |
Y friction restraint reaction limit as proportion of normal reaction |
(Real) |
Fz |
Z friction restraint reaction limit as proportion of normal reaction |
(Real) |
|
|
|
Extra lines for variable stiffness tables: |
Axis,Step,Disp,Stiff |
|
Axis |
1=X translation, 2=Y translation, 3=Z translation 4=X rotation, 5=Y rotation, 6=Z rotation |
(Integer) |
Step |
Step number in table |
(Integer) |
Disp |
Translation or rotation in table |
(Real) |
Stiff |
Axial or rotational spring stiffness in table |
(Real) |
Rest choices are "F"=Fixed, "R"=Released, "S"=Spring, "V"=Variable, "P"=Plastic or "N"=Friction. "N" can only be used for the translation restraints (ie. the first three positions in the restraint code).
If an "N" friction restraint is specified then the axis normal to the friction axis and the friction limit as a proportion of the reaction in the normal direction must also be specified. The friction restraint can also be activated based on a positive-only or negative-only reaction in the normal direction. For example, if the vertical axis in your model is Y, and a friction restraint in the X direction is required that is limited to 10% of the vertical reaction, but only if the vertical reaction is upwards (ie. vertical load is downwards) then you would specify an "N" in the first position of the restraint code, with Nx="Y" (the axis normal to the friction restraint), Dx="P" (so that the friction restraint is only activated if the normal reaction is positive) and Fx=0.1 (so that the friction reaction is limited to 10% of the normal reaction).
Dirn choices are "P"=Positive only, "N"=Negative only, "B"=Bi-directional.
Dx,Dy,Dz choices are "P"=Positive only, "N"=Negative only, "E"=Either direction.
Gr choices are "Y"=General restraint, " " or "N"=Normal restraint. There can be only one general restraint in the job.
The extra lines for variable stiffness tables are required whenever a "V" restraint is used. Each "V" restraint will typically have multiple lines in its variable stiffness table, each with an Axis number that matches the position of the "V" in the restraint code and Step numbers that increment upwards from 1 (eg. 1,2,3,...etc). For example, a restraint code of "FVFRRR" with variable stiffnesses in the Y direction of 10000, 20000 and 25000 that correspond to vertical translations of 0, 150 and 200 mm respectively, could have the following lines in the variable stiffness table:
2, 1, 0.0, 10000.0
2, 2, 150.0, 20000.0
2, 3, 200.0, 25000.0
If there were multiple "V"s in the restraint code then the stiffness tables for each "V" would just follow one after another, each with an Axis number that matches the position of the "V" in the restraint code and Step numbers that start at 1 for each table.
For further information on restraints, refer to "Node restraint data".
If there are no variable spring, plastic, friction or one-way restraints then the format reverts back to the following simplified form with just one line per restrained node:
Line 1: |
RESTRAINTS |
|
Next n lines: |
Node,Rest,Gr,Gen,Ni,STx,STy,STz,SRx,SRy,SRz |
|
See also Node Restraint Data.