Initialize Tooling Temperature with Previous Simulation

NarendraSingh
NarendraSingh
Altair Employee
edited April 2023 in Altair HyperWorks

Extrusion tools ( die, container, etc) are pre-heated before they are loaded into the extrusion press. If extrusion tools are not heated to the correct temperature then there is the risk of premature die failure, incorrect metal flow, and sticking billets. Most extrusion plants set the die oven at a fixed temperature in the range of 450 °C – 500 °C and rely on time to control the temperature.

The benefit of preheating:

  • reduce the risk of premature die failure.
  • achieve thermal stability in fewer billet cycles.
  • reduce the amount of scrap produced at the start of a production run attributed to uneven metal flow.
  • avoid the cost of the lost production associated with sticking billets.

For the first few billet cycles, the whole press (including the die tool) will not achieve a cycle steady state temperature. Hence to get the correct simulation, we must run the simulation for at least 5-10 billets to reach steady state; this significantly increases computation time. HyperXtrude solver allows us to re-use computed temperature from one simulation into another. 

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How to setup

  1. Setup transient coupled analysis containing both workpiece and tool mesh with one or more billet cycle configuration
    1. Sample Model RodModel_CoupledHXHX_MultipleBilletCycle.zip
  2. Launch solver with solver deck from #1.
  3. Once the simulation is complete, you will notice several *.fem (e.g RodModel_c01t005.fem) file in the run solver.
    1. This *.fem file is OptiStruct solver deck containing mesh, temperature, pressure, and constrains information.  
    2. "_c01t005" suffix in the FEM file name means - Billet Cycle # 1 (written as c01) and time step 5 ( written as t005).
  4. Create sub-folder with name "run2_IntializeToolTemperature"
    1. copy solver deck from #1
    2. copy *.fem for respective billet cycle and time step
    3. rename the *.fem to InputToolTemperature.fem
  5. Edit HX file
    1. open <model name>.hx file
    2. write following line 
    3. pset InitToolTempFromFemFile  yes
  6. Launch solver
    1. Sample Deck: RodModel_CoupledHXHX_MultipleBilletCycle_WithTemperatureInitialize.zip
  7. Verify temperature at time 0 is the same as in the first simulation of the selected billet cycle and time step. 

How to save computation time when running multiple cycle analysis:

Depending on need, use the following flags in .hx file. This can significantly reduce file size and improve computation time. 

  • pset H3DSaveOptionalResults 0
    • if the goal is temperature then turn off all optional results. This will save time in writing and also reduces the size of H3D file
  • pset H3DUnitSystem User
    • solver writes two H3D file. if you are going to post-process results in H3D then set it to User. The solver will not write SI unit H3D file. 
  • pset FemFileSaveFrequency 5
    • at each time step, the solver by default write *.fem file. if you do not need it at every time step then have an increment of Nth time. Default is 1.
  • pset SavePHXfileYesNo 0
    • this file is needed to restart the solver. if you turn off this then you can same I/O time. 

 

 

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