NOLIN4
Bulk Data Entry Defines nonlinear transient forcing functions of the form.
Where, may be a displacement or a velocity at point GJ in the direction of CJ.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
NOLIN4 | SID | GI | CI | S | GJ | CJ | A |
Example
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
NOLIN4 | 2 | 4 | 6 | 2.0 | 101 | 16.3 |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
SID | Nonlinear load set
identification number. No default (Integer > 0) |
|
GI | Grid or scalar point
identification number at which nonlinear load is to be
applied. No default (Integer > 0) |
|
CI | Component number for
GI. No default (1 ≤ Integer ≤ 6; blank or 0, if GI is a scalar point) |
|
S | Scale factor. No default (Real) |
|
GJ | Grid or scalar point
identification number. No default (Integer > 0) |
|
CJ | Component number for GJ, GK according to the following table. | |
A | Exponent of the
forcing function. No default (Real) |
Type | Displacement | Velocity |
---|---|---|
Grid | 1 ≤ Integer ≤ 6 | 11 ≤ Integer ≤ 16 |
Scalar | Blank or 0 | Integer = 10 |
Comments
- Nonlinear loads must be selected by the Subcase Information data selector NONLINEAR.
- Nonlinear loads may not be referenced on a DLOAD entry.
- All degrees-of-freedom referenced on NOLIN4 entries must be members of the solution set.
- Nonlinear loads may be a function of
displacement
or velocity
. Velocities are denoted by components ten
greater than the actual component number; that is the component 11 indicates
velocity in the 1 component direction. The velocity is determined
by:Where,
- Time step interval
- Displacement of GJ-CJ for the previous time step.
- Use a NOLIN3 entry for the positive range of .
- The time step algorithm in transient solution sequences may loose unconditional stability when this load entry is used. In most practical cases, the time step size chosen to reach a certain accuracy is below the stability limit. It is recommended to decrease the time step if results diverge.