Welcome to the LS-DYNA Product Space

Hi,

I have been getting out of range velocities at the nodes, despite the fact that the element velocity are well within range.

How to solve this error?

Thanking you

Pratik Ganorkar (pratik2116303@iitgoa.ac.in)

MTech, Mechanical Engineering

Indian Institute of Technology, Goa

Hi, I developed UMAT, compiled and run the solvers.

but there's no response in solver windows like below

So i tried the default UMAT file without my code and also there happens a problem

What's wrong with this??

Please help me. I appreciate your help

Thanks

I am trying to sum two curves together to get the correct mass flow rate to be used with AIRBAG_WANG_NEFSKE (lcmt). When running the simulation, the curve function works correctly (I am able to see the result from curveout), but there is no mass flow applied to the airbag. Is there a way to be able to use a curve function for lmct?

Thanks,

Kyle

Dear Ansys suppot team

How to apply a moment befor ls dyna analysis. as shown in below fig.

Can someone outline the steps to apply a moment to a deformable body in Workbench LS-DYNA without the use of command snippets? It seems it is not possible; you must make use of some rigid body connected to the deformable body and then use the Rigid Body Tools to apply a moment. Is this limitation correct?

In standalone LS-DYNA is the recommended approach to apply a moment to a deformable body to use *CONSTRAINED_INTERPOLATION as is described in this example?

Hi,

I am trying to automate my post process analysis since a have many different simulations going on. I want to understand what is exactly in d3plot? Or how LSPP treats them?

1. Do d3plot files contain derived output or only tensors? Using lasso-python library in python, I am only able do access stress and strain tensors... meaning I have to calculate Von Mises from the tensors at each elements for each state...
2. Is there a way to flag certain derived output in d3plot which I can access with lasso-python library? It looks like LSPP computes derived outputs from tensors in d3plot (insetad of only retrieving derived outpouts, it computes it)

How to you access the data you can fringe in LSPP via d3plot and wihtout using LSPP at all? Do I really have to calculate all derived outputs myself?

Thank You

Is there a way to get model size info (number of nodes, beams, solids, etc) written into lsrun.out or another human readable file without using LS-PrePost.

I'd like to see this information:

I see that LS-DYNA only writes to lsrun.out every time it writes a d3plot file or flushes I/O buffers.

Is there a way to make it output this information every N cycles instead, regardless if it is performing either of these operations?

I wanted to know if LS-DYNA program manager still exists, and, if so, where can I download it? Or is LS-Run now the primary way to run analyses through LS-DYNA?

Hi everyone, 

I need some help again please :)

I have performed an impact simulation with a bird defined as a water liquid impacting upon a stretched acrylic laminate. When viewing the directional deformation, these large jagged elements appear, how do i troubleshoot this issue?

can the Students version of LS-Dyna be Integratet in the Workbench environment? if yes how?

Hi,

I am trying to simulate crash impact conditions using GHBMC-50 Model, I have included the impact condition as seprate file. when I do included my boundary contion and run the simulation , I am getting an error messege, "the termination due to out-of-range forces and moment number of nodes having out-of-range". Please any advise to overcome this problem will be really appriciated 

I am looking forward to hearning from you soon

Best Regards

Hamid 

I see that Body Interaction in Workbench LS-DYNA creates a *CONTACT_AUTOMATIC_SINGLE_SURFACE card in the input file.

The card created via Workbench:

is very different than the description of the card in LS-PrePost

What is the difference here?

Hi,

The ball plate impact analysis which I have been using takes very long time to process and the time required to process increases as I refine the plate mesh.

How can I reduce the processing time for finer mesh ? 

Please share your knowledge with me.

Thanking you

Pratik Ganorkar (pratik2116303@iitgoa.ac.in)

MTech, Mechanical Engineering, IIT Goa

hi, when I am trying to define sph to sph coupling, LS-DYNA force exits (crashes).

may someone help me with this problem?

also, what type of contact should I select for cold spray (droplet and substrate are both sph)?

Hi all,

I would appreciate some guidance. I am using ANSYS LS-DYNA through workbench 2023 R1 and am trying to set up a bird strike simulation for a laminated aircraft window. In doing so i believe i need to specify the body interactions between the plies of the window as 'bonded'. When i do so, the following error comes up:

Can anybody point out where i am going wrong and how to move forward please?

Ash 

Hello everyone,

I am trying to solve a 2d problem, with a structured ALE mesh interacting with a Lagrangian structure. After a certain time, the material in the ALE mesh develops a very small timestep, so I would like to delete it using TDEATH. However, when the mesh is deleted, the simulation ends with the following message:

**** Error 40178 (SOL+178)
Material type 0 is unavailable for
2D plane and axisymmetric elements

Does anyone have a suggestion what is happening? i only used material types with other numbers.

Thanks!

Hi,

I have a user defined material model and it gives similar results when highly meshed and single element  stress strain testing outputs in tensile, compression and shear.

But, when I do a  low velocity impact on that material with spherical steel ball on surface of plate made up of the user defined material, then the force-displacement graphs are mesh dependent, with fine mesh acting more softly compared to coarse mesh which acts more hard.  The results are expected to be mesh dependent. What could be the possible reasons for mesh dependencies?

Please share your knowledge with me.

Pratik Ganorkar (pratik2116303@iitgoa.ac.in)

MTech, Mechanical Engineering, IIT Goa

Dear all,

I received the SMP DP R14 version of LS-DYNA through secure transfer, for both Windows and Linux.
The object version when compiled in Windows works as expected. The same object version when compiled for Linux (HPC application) throws a license error (see below).
The models were run on a single node of the HPC (40 cores) for which LS-DYNA SMP DP R13 works. The Windows R14 object version, points to the same license server and also works.
Have you had any such issues in the past?

Best Regards,

George

hi, I am a  learner for Ls_dyna,now counting a problem like this

please help me

thank you!!

Hi,

I encountered this error when I started a simulation.

forrtl: severe (157): Program Exception - access violation

There is no error in the message file.

As seen below, I am getting a negative value related to the added mass.
Could the problem be caused by this?
If not, what could be the reason for this?

Below are the timestep values I entered in the .k file.

*CONTROL_TIMESTEP
$#  dtinit    tssfac      isdo    tslimt     dt2ms      lctm     erode     ms1st
       0.0       0.9         0       0.0-3.2000E-7         0         0         0
$#  dt2msf   dt2mslc     imscl    unused    unused     rmscl     emscl      ihdo
       0.0         0         0                           0.0                   0

Thanks!

hi i download above image ansys workbench. and i wanted to use ls-dyna that is in workbench

but when i tried to run the ls dyna the error message comes out like

'the demanded solver was not found in the specified path' what can i deal with it

do i also need to download the ls-dyna student version like below. thank you

Hi, nice to meet you all. I am new on this forum and I am wondering I can get some help here.

I am working on drone body drop test from 1m using explicit dynamic. The drone body is made by carbon prepreg layers using ACP-pre.

Here is the set up:

And here is the analysis setting in the model in explicit dynamic:

After the solver is done, it seems the drone doesn't impact with the concrete below ( the droen body just simply overlap with the concrete )

So I have a few questions:

1. Could the overlapping caused by insufficient maximum number of cycle?
2. Is it ok for me to keep to number of step in analysis setting as 1? I have learnt that times steps are actually controlled by the smallest mesh size.
3. Does the end time refer to the duration of the whole process? ( start from the moment of dropping to after impact ) or it referes to the duration of impact? And is there a good way to determine to end time? 

I would appreciate any help here.

Thank you

Hi,

NODAL_FORCE_GROUP is used to obtain force on selected node set by user. In  my case, I  am getting the force output in one case but in another (more nodes) case  the LS-DYNA stops responging and I have to force quit my interface. Why does this happen? Is there some limit on number of nodes that can be used for force analysis.

Is there any other way I can obtain force on a Part which I am using in impact analysis. 

Please share your knowledge with me.

Pratik Ganorkar (pratik2116303@iitgoa.ac.in)

MTech, Mechanical Engineering, IIT Goa 

Hello,

I'm working on a graduation project to simulate the creasing process of corrugated cardboard, which has three layers (Inner, Flute, and Outer). The folding lines of the cardboard box are made using a long ruler fixed on a rotating cylinder, and each line takes no more than 200ms to crease.

The previous student who worked on this project used static analysis with COMSOL, but their model wasn't successful because it didn't consider the buckling effect of the material. Now, I'm not sure which analysis method or software to use for my project. Should I use static or dynamic analysis? Implicit or explicit?

Based on my research so far, I'm leaning towards dynamic explicit analysis using LS-DYNA. This is because the load is applied to the material very quickly, causing non-linearity due to material properties, contact, and buckling. Additionally, LS-DYNA has a material profile specifically for paper (*MAT-PAPER).

I'm still unsure about which method to use and whether it should be studied dynamically. Any guidance or help would be greatly appreciated.