Analysis Control

*ANTP: Analysis Type

*ANTP

i1: i*4: Analysis type number

2: Transient Heat Transfer

4: Quasi Static Mechanical

This card is used to specify the analysis type.

*CMSH: Check MeSH

*CMSH

This card pauses the simulation after the auto-generation of a mesh during the thermal analysis. It will prompt the user to continue the simulation or exit. This allows the user to examine the auto-meshing of a new geometry without running the full simulation. This card has no effect during the mechanical portion of the simulation.

*NLTL: Total Lagrangian Analysis Switch

*NLTL

This option allows for mechanical analyses to be performed using the Large Deformation formulation. By default, the small deformation formulation is used.

*OFC1: OFf Core Pre-processing Stage 1

*OFC1

This option writes certain pre-processing arrays to Direct Access files instead of allocating in RAM. Enable this option to reduce the RAM requirements demanded by simulations using large numbers of degrees of freedom. This option can be used in conjunction with *OFC2 for even more memory intensive simulations.

*OFC2: OFf Core Pre-processing Stage 2

*OFC2

This option writes certain pre-processing arrays to Sequential Access files and deallocates from RAM during solution. These arrays compromise a different set than those written to Direct Access Memory using *OFC1. This option should be used in conjunction with *OFC1 for even more memory intensive simulations.

*RELA: Relaxation Control

*RELA

i1, r1

i1: i*4: number of iterations. Default 0

r1: r*8: Scaling factor. Default 1.d00

This card allows for the step size of the Newton-Raphson solver to be scaled by r1 for i1 iterations. The purpose of this option is to stabilize the solver and/or accelerate convergence.

Best Practices:

Thermal analysis should converge using 1, 0.4 Excessive non-linearities caused by material properties or using *LATE may require using more relaxation iterations, i.e. 2, 0.4.

Mechanical analysis should converge 1, 0.2 This is the default value used by GUI. If the simulation does not converge, increase the number of iterations, i.e. 2, 0.2

*SOLU: Solution Parameters

*SOLU

i1, r1, r2

i1: i*4: max number of iterations. Default 30

r1: r*8: residual tolerance. Default 1.d-2

r2: r*8: max residual. Default 1.d20

This card controls the Newton-Raphson solver. If the solution does not converge within i1 iterations at any given time step, the time step size will be reduced and the solver will cutback. Once the residual is smaller than r1 the simulation will continue to the next time step. If the max residual exceeds r2, the analysis will be automatically terminated.

*TRAN: Transient Analysis Timing Control

*TRAN

r1, r2, r3, r4, r5, r6, i1, i2

r1: r*8: start time

r2: r*8: end time

r3: r*8: initial time increment

r4: r*8: maximum allowable time increment

r5: r*8: minimum allowable time increment

r6: r*8: incrementation tolerance

i1: i*4: maximum number of cutbacks

i2: i*4: maximum number of increments

This card sets the simulation start and end time as well as the initial, maximum, and minimum time increments.
The card is also used to specify the incrementation tolerance which controls how quickly time steps increase to the maximum value during cooling.
Also sets the maximum number of allowable cutbacks and increments. If the maximum number of cutbacks or increments is exceeded, the analysis will be terminated.

Best Practices

r3: To avoid aliasing, analysis of direct processes and moving source models should have increments so that the time steps are equal to the time it takes for the laser to move 1 laser radius. This can be automated by using *TAUT to control the time incrementation.
r4: Allowing for larger maximum time increments (10-1000s) can decrease the time it takes to complete a simulation for those builds with larger deposition times or long post-process cool down times. However if the time steps are large compared to the time scale of the cool down periods, there may be an undesirable loss of resolution.
i2: If the simulation will take more than 99,999 increments, ensure *OFNS is used so the simulation does not end prematurely.

*TAUT: Automatic Time Incrementation Based on Heat Source Radius

*TAUT

r1: r*8: time in sec. Default 1.d0

This option is used in moving heat source analyses to automate time incrementation. When a heat source is active, the time increment is set to radius/velocity*r1, meaning that if r1 is set to 1, the heat source will move a distance equal to its radius at each time step. Using a r1 value 0.5 will move one half laser radius per time step, and so forth.

Best Practices: For moving source models *TAUT should be enabled and alteration of time steps should becompleted using the *TAUT r1 value.

*TPRM: Dwell Time Multiplier for PRM Generation

*TPRM

r1: r*8 time in sec. Default: 20

This card is used to alter the timing during PRM generation. TPRM is used to account for the time required to deposit the rest of the volume of the part or parts that will be simulated using the PRM file that will be generated. The value r1 is multiplied by the recoater time to create the dwell between the layers simulated by the moving source PRM generation model.

*TWAL: Wall CPU Limit

*TWAL

r1: r*8: time in sec

This option terminates execution and saves results if the wall CPU time exceeds r1. This option is useful when running in clusters using PBS so that the results are saved before the analysis is terminated.