NOLIN4

Bulk Data Entry

NOLIN1 – Nonlinear Transient Load as a Negative Variable Raised to a Power

Description

Defines nonlinear transient forcing functions of the form

nolin4_1

where, Xj(t) 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

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
NOLIN4	2	4	6	2.0	101		16.3

Field

Contents

SID

Nonlinear load set identification number.

No default (Integer > 0)

Grid or scalar point identification number at which nonlinear load is to be applied.

No default (Integer > 0)

Component number for GI.

No default (1 < Integer < 6; blank or 0, if GI is a scalar point)

Scale factor.

No default (Real)

Grid or scalar point identification number.

No default (Integer > 0)

Component number for GJ, GK according to the following table:

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

Exponent of the forcing function.

No default (Real)

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 NOLIN4 entries must be members of the solution set.

4.	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

nolin1_5

where, is the time step interval and is the displacement of GJ-CJ for the previous time step.

5.	Use a NOLIN3 entry for the positive range of Xj(t).

6.	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.