2d to 3d ale mapping

[Shubham Sharma]

I am trying to validate the attached research paper. I have scaled the 2d shell mesh at the circumference by 10 per cent to make it bigger than the 1/8th of the sphere solid mesh that I have generated using blockM, following this video "https://www.youtube.com/watch?v=Q7iUIKRJro4". I am getting the following error: " Error 40500 (SOL+500)
     Node #275500 has out-of-range velocities" for several nodes. 

Now, my shell mesh is in the XY plane with y as the symmetric axis. Can someone share some insights on how to handle this? 

[l...@schwer.net]

The “out-of-range velocities” is often caused by too large a timestep.

Try setting the *CONTROL_TIMESTEP parameter TSSFAC=0.6, or smaller.

                              --len

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[Shubham Sharma]

The control time step parameter was set to 0.33, I was not sure about the one eighth spherical mesh generated for water by blockM so I tried first mapping a 2d square blast loading to a 3d cube mesh for water, the mapping is happening here but the blast waves are all over, I have attached the files also, any insight will be of great help

[l...@schwer.net]

I changed the value of DCT on *CONTROL_ALE from 2 to -1 in both input files and that seemed to make the difference.

 

Note: the paper you were following correctly is fairly OLD (2008) and LS-DYNA has changed in the past 18 years 😊      --len

 

From: 'Shubham Sharma' via LS-DYNA2 <ls-d...@googlegroups.com>

Sent: Saturday, April 18, 2026 10:58 AM
To: LS-DYNA2 <ls-d...@googlegroups.com>

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[James Kennedy]

From the User’s Manual (*CONTROL_ALE):

 

2. The DCT Field. For the general ALE solver in both 2D and 3D, the DCT field

specifies the advection scheme. By default, the solver uses the original advection

scheme. Setting DCT = -1 invokes the improved advection scheme. The S-ALE

solver in both 2D and 3D always uses the improved advection scheme (DCT is

ignored).

 

We recommend DCT = -1 over the default scheme, especially for simulating explosives.

This scheme includes the following major changes:

 

a) Relaxes an artificial limit on the expansion ratio limit. The default limit improves

stability in some situations but can overestimate the explosive impulse.

 

b) Corrects redundant out-flux of material at corner elements. The redundancy

can lead to negative volume.

 

c) Removes several artificial constraints in the advection which were originally

implemented to assist in stability but are no longer needed.

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