# NOLIN1

Bulk Data Entry Defines nonlinear transient forcing functions of the form.

Function of displacement:(1)
${P}_{i}\left(t\right)=S·T\left({u}_{j}\left(t\right)\right)$
Function of velocity:(2)
${P}_{i}\left(t\right)=S\cdot T\left({\stackrel{˙}{u}}_{j}\left(t\right)\right)$

Where, ${u}_{j}\left(t\right)$ and ${\stackrel{˙}{u}}_{j}\left(t\right)$ are the displacement and velocity at point GJ in the direction of CJ.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
NOLIN1 SID GI CI S GJ CJ TID

## Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
NOLIN1 21 3 4 2.1 3 10 6

## 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, according to the following table:
TID Identification number of a TABLED1, TABLED2, TABLED3, or TABLED4 entry.

No default (Integer > 0)

Type Displacement Velocity
Grid 1 ≤ Integer ≤ 6 11 ≤ Integer ≤ 16
Scalar Blank or 0 Integer = 10

## Comments

1. Nonlinear loads must be selected by the Subcase Information data selector NONLINEAR.
2. Nonlinear loads may not be referenced on a DLOAD entry.
3. All degrees-of-freedom referenced on NOLIN1 entries must be members of the solution set.
4. Nonlinear loads as a function of velocity 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: (3)
${\stackrel{˙}{u}}_{j,t}=\frac{{u}_{j,t}-{u}_{j,t-1}}{\Delta t}$
Where,
$\Delta t$
Time step interval.
${u}_{j,t-1}$
Displacement of GJ-CJ for the previous time step.
5. 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.