*STRF
r11, r12: temperature 1 [°C], time 1 [s]
r21, r22: temperature 2 [°C], time 2 [s]
r32, r32: temperature 3 [°C], time 3 [s]
This card is used to set the temperatures and times for stress relief heat treatment. Heat treatment modeling requires plasticity to be enabled by addition of the *PPLA card. Stress relaxation (recrystallization) temperatures must be specified using the *STRR card to enable stress relief simulation. Cooling rates can be controlled using *ACNV.
The times in the *STRF card refers to time after the end of the thermo-mechanical build simulation and post-process cool down. The heat treatment modeling occurs after the plasticity modeling, but before the part is removed from the build plate.
If a final temperature has been specified by *FINT, that is the starting temperature for the heat treatment simulation. If no final temperature is specified, then the initial temperature set by *INIT is used. If an initial temperature has not been explicitly stated, then the ambient temperature is used as the heat treatment starting temperature, as set by *AMBI. Additional time steps may be added based upon convergence requirements.
Required Cards: *STRR, *PPLA
Best practices
For heat treatment where the final cool-down takes an unknown amount of time, it is recommended that a long period of time (12 hours+ depending on the thickness of the part) be added between the penultimate and ultimate heat treatment step, to ensure that the part can come naturally to the specified final temperature. Follow the meshing practices advised under the *PPLA best practices section of using *PBLR values of 0 or 1, and performing additional mesh convergence checks, to ensure that the mesh is dense enough to adequately capture the modeled behavior.