TSTEPNL

Bulk Data Entry Defines parameters for Nonlinear Direct Transient Analysis.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
TSTEPNL ID NDT DT     KSTEP   CONV  
  EPSU EPSP EPSW     MAXLS   LSTOL  

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
TSTEPNL 99   0.01            

Definitions

Field Contents SI Unit Example
ID TSTEPNL Bulk Data cards must have a unique identification number.

No default (Integer > 0)

  
NDT Number of load sub-increments.

No default (Integer > 0)

  
DT Initial time step.

No default (Real > 0)

  
KSTEP Number of iterations before stiffness update.

Default = 6 for BCS solver

Default = 3 for PCG solver

(Integer > 0)

  
CONV Flags to select convergence criteria.

Default = UPW

(Any combination of U, P and W)

  
EPSU Error tolerance for displacement (U) criterion.

Default = 1.0E-2 (Real > 0.0)

  
EPSP Error tolerance for load (P) criterion.

Default = 1.0E-2 (Real > 0.0)

  
EPSW Error tolerance for work (W) criterion.

Default = 1.0E-3 (Real > 0.0)

  
MAXLS Maximum number of line searches allowed for each iteration.

Default = 20 (Integer > 0)

  
LSTOL Line search tolerance.

Default = 1.0E-3 (Real > 0.0)

  

Comments

  1. The TSTEPNL Bulk Data Entry is selected by the Subcase Information command TSTEPNL = option.
  2. In Nonlinear Direct Transient Analysis, TSTEPNL may be utilized as a replacement for some parameters in the NLPARM Bulk Data Entry. However, not all entries of the TSTEPNL Bulk Data Entry will be effective. Specifically, when TSTEPNL is used, instead of NLPARM, the fields DT, KTSTEP, MAXITER, CONV, EPSU, EPSP, EPSW, and LSTOL will be used with the same meaning of the corresponding entries of NLPARM. Additionally, NDT will be used as NINC of NLPARM. The rest of the values of NLPARM and TSTEP that are not issued by TSTEPNL, will assume default values. Using both TSTEPNL and NLPARM in a subcase is not supported.
  3. This card is represented as a load collector in HyperMesh.