r/Abaqus

I was trying to map Abaqus standard results to CEL. Is there anyone who can help me in this regard?

Hello,

I would like to analyse the strain and stress of an aluminium piece for sailing. The piece is the aluminium low friction ring displayed in BLACK in the photo.

This ring is hold by two ropes in tensions, which applied loads on this ring.

I need to model how the rope interacts with the aluminium ring probably.

I don't know how to model a rope like this.

I try with an orthotropic material, but I didn't achieve to do the right parameters for the contacts between the metal piece and the rope.

Should I use abaqus Explicit for such an analysis ?

How to parameter the rope material for a realistic results ? Anisotropic ? Which values ?

If you have any kind of tutorial that I could watch or read, I'm interested.

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Buenas chicos, hoy me he encontrado con un problema en el trabajo. Estoy intentando hacer un modelo donde una orejeta macho unido mediante un bulon a unas orejetas hembra se carga, en primer lugar con una carga horizontal/axial y luego con una carga vertical. El modelo tiene una serie de tornillos 3D con pretension que atan dos placas que evitan que se abra la orejeta hembra. Estas cargas las divido en tres STEPs:

- Pretension

- Carga axial

- Carga vertical

Para los dos primeros steps tengo restringido 13456 la SURFACE donde se aplica la carga. Obviamente la carga se aplica en 2 en el step 2. Para el step 3 libero el grado de libertad 3 para poder aplicar la carga pero aquí viene el problema.

Para la pretension utilizo *PRE-TENSION SECTION en los tornillos. Luego en el step 2 utilizo *BOUNDARY, FIXED para fijar la pretension del step 1 y que no desaparezca. El problema viene en el step2 que para poder eliminar el grado de libertad tengo que usar *BOUNDARY, OP=NEW y reescribirlas todas. Cuando haces eso ya no puedes volver a usar fixed, y evidentemente se destensa el modelo en el tercer step.

¿Como hago para mantener la pretension en ese step? Tengo varias ideas, como medir la deformación del nodo de la pretensión en el primer step y meterselo en el step 3 como desplazamiento forzado, o volver a meter la carga de pretensión ya que a medida que se descarga, se vuelve a cargar con la pretension que le meto.

Estoy en regimen No lineal, y los 3 steps son mandatory

Gracias chicos.

https://preview.redd.it/8l6qbjwhox0h1.jpg?width=1280&format=pjpg&auto=webp&s=090a6c5fcb83899889e74dab269fad87cdcdb0f3

Ever imported a CAD part and couldn't get a structured mesh and faced the “regions cannot be meshed automatically" error, while tet meshing takes way too much computing time?

In this tutorial, I show you step by step how to:
• Partition complex geometry into simple, meshable blocks

• Force Abaqus to create a structured C3D8R hex-mesh

I also demonstrate how to sweep your mesh across partitions for perfect element transitions instead of relying on default settings.

Watch the full video on the YouTube channel: YouTube Channel

Hi all,

I am modelling a stiffened composite panel under displacement loading (uniaxial compression). I am using S4R elements for both the skin and the stiffener, and the stiffener foot is tied to the skin.

On the transverse edges, I apply u1=1 and u1=-1 in the loading step. I also constrain u2=0 at both the bottom-left and bottom-right skin nodes (in the initial step). In addition, the outer perimeter edges of the skin are constrained with u3=0 (again in the initial step) to model a simply supported case.

The static loading step works perfectly, with no issues. However, when I switch to a buckling step, I get the following message:

"The differential matrix has 83003 negative diagonal entries."

I have never seen this before, and I have no idea what could cause this kind of behaviour.

Any ideas would be very welcome.

P.S. I've already checked the shell normals, section assignments, material orientation, tie constraint (master vs slave), etc. All looks OK to me, so I'm very clueless. Mesh is nice, structured with fine enough elements, etc.

Panel under consideration.

B.C. around the panel edges.

Loading on the panel.