NOLIN4

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

P i ( t ) = { S [ X j ( t ) ] A , X j ( t ) > 0 0 , X j ( t ) 0

Where, X j ( 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

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

  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 ( X j = u j ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaaca WGybWaaSbaaSqaaiaadQgaaeqaaOGaeyypa0JaamyDamaaBaaaleaa caWGQbaabeaaaOGaayjkaiaawMcaaaaa@3CA6@ or velocity ( X j = u ˙ j ) . 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:
    u ˙ j , t = u j , t u j , t 1 Δ t
    Where,
    Δ t
    Time step interval
    u j , t 1
    Displacement of GJ-CJ for the previous time step.
  5. Use a NOLIN3 entry for the positive range of X j ( t ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiwamaaBa aaleaacaWGQbaabeaakmaabmaabaGaamiDaaGaayjkaiaawMcaaaaa @3A7A@ .
  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.