Transient Heat Transfer with 100 Time-Dependent Data Surfaces in FEMAP

[test123123]

Hello FEMAP Community,

I’m working on a transient heat transfer analysis using FEMAP and NX Nastran, and I could use some guidance. My goal is to apply surface temperature distributions that change every 20 seconds over 100 time steps (totaling 2000 seconds). I’ve created 100 Data Surfaces, each representing the temperature distribution at a specific time (e.g., t=0s, t=20s, ..., t=1980s), but I’m struggling to apply them sequentially in a time-dependent manner.


This is an example of a heat distribution data surface.

Here’s the setup:
- **Objective**: Apply each Data Surface as a boundary condition at 20-second intervals to calculate the temperature evolution, including radiation effects.
- **Issue**: I can’t figure out how to efficiently apply all 100 Data Surfaces across the time steps.
For example, I want to apply Data Surface 0 at 0 seconds, Data Surface 1 at 20 seconds, Data Surface 2 at 40 seconds, and so on......

What I’ve tried:
1. SOL 159 and Sol 401
2. Using a single time-dependent function (Function vs. Time), but this doesn’t work since Data Surfaces are spatial distributions, not simple scalar values.
3. Considering manual edits to the NX Nastran .dat file, but I’m unsure how to link Data Surfaces to time steps (e.g., with TLOAD1 cards).

My questions:
- I think nonlinear multistep (SOL401) would be more appropriate than transient heat transfer (SOL 159)analysis. Is that correct?
- Is there a way in FEMAP to automate applying 100 Data Surfaces over time steps?
- Could an API script or .dat file modification solve this? If so, could someone share a simple example or workflow?
- For those who’ve tackled similar tasks, what approach would you recommend?

Any help would be greatly appreciated—thank you in advance!

 

[karachun]

Look like instead of Data Surfaces you should apply temperature individually to each node and each of this load should use its own unique temperature vs time but this will be time consuming if made by hand - thousands of loads and functions.

Try to ask on Siemens community, maybe users there can write some API for you if it is not too complex.

https://community.sw.siemens.com/s/topic/0TO4O000000MikcWAC/simcenter-femap

SOL 401 is nonlinear structural solver, not thermal solver. As I know It can only take temperatures as input and calculate thermal strain. It do not have heat transfer calculation capabilities (conduction/convection/radiation). Have you tried to solve some simple thermal problems like hear transfer in rod in SOL401. Try it and check if 401 has any heat transfer capabilities.

UPD. As alternative to API script you can use Macro Recorder. It don`t require programing skills. You should first create all necessary temperature vs time functions (maybe using excel), export them into Femap and make sure that node numbers and function numbers are coincident (like node 1000 has corresponding function with 1000 ID). Than you can run macro recorder, record creation of couple of loads and than copy that commands using excel. Still a lot of work but at least load creation will be automated.