Dear Abaqus users,
have any of you ever wondered about the calculation or the units of NFLUX Abaqus output? I have been executing a coupled temperature-displacement simulation for an isotropic material in form of a thin wire. While I provide a constant body flux heat (HBF) to a two node truss element I notice a "delay" in temperature elevation as seen in the following figure.
My first though is that this "delay" is caused by conduction, thus I requested the NFLUX output, which is described as "Fluxes at the nodes of the element caused by the heat conduction or mass diffusion in the element (internal fluxes)" in the Abaqus manual. Nevertheless, I cannot address how it is calculated or how I can change its effect (I tried to set conductivity to 0, but I received the same response).
Any thoughts/suggestions would be really helpful and more than welcome.
Thank you,
Anargyros
Dear Anargyros,
ABAQUS software is unit-independence and units are defined by user. Therefore, reliability of the result is also with user. The delay is also odd for me, maybe you can check initial and step in boundary condition.
Dear Pedram,
thank you for your answer. You are right about the units. Sorry for not stating in my question that by referring to units I meant either SI or expressed in Abaqus format. For example, conductivity, k is expressed in units of J T^–1 L^–1 θ–1.
The initial conditions and BCs have been checked and are quite simple. Initial predefined fields include the initial temperature of the wire, while BCs include only the structural support of the wire (clamped - free ends). There are no other interactions or thermal BCs. The goal is to apply a constant force and afterwards increase the temperature of the wire.
Kind regards,
Anargyros
Dear Anargyros,
It seems that you are sure about the boundary condition and I believe it. I have better solution for you, you can take a look at abaqus documentation in the link below:
http://simulace15:2080/v2016/
In this page if you search for nflux, you can find something about output, analysis procedure and output variable (attached photos 1 and 2) . Besides, if you change abaqus analysis user's guide to abaqus example problems (attached photo 3) guide you can find some input files which were created by abaqus team. I hope if I can help you efficiently.
Dear Pedram,
thank you for taking time to look into my question. As you suggested, I have already done my search in Abaqus documentation and I have read all the sections you posted. Unfortunately, there is nowhere a clarification about the units, the calculation process or anything related. Most of the links just repeat what NFLUX represents or how it is defined. Even in the Results of the Abaqus Visualization module, where for every plot Abaqus informs the user about the output type (for example Temperature, Heat Flux per Unit Volume etc.), the label for NFLUX returns "none".
Thank you for your time,
Anargyros
- Badges
- Science topic
- Similar topics
- Mathematics
- Algebra
- Matrix