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Error "severe (157): Program Exception - access violation"  

 

dan.mnation
(@dan-mnation)
New Member
Joined: 1 month ago
Posts: 2
August 5, 2020 4:52 am  

Hi all,

Relative noob here. I am a student working on an impact test on a bicycle helmet design with a Biofidelic head model. I keep having issues in solving the study at a set point it crashes continually with an error "forrtl: severe (157): Program Exception - access violation". I have run successful tests in an identical setup with a ballast head model (no internal organs etc) with great results. I am wondering if anyone has any ideas as to what causes this problem. I have a suspicion that when I set up the head model in the current tests, there may be an issue with my contacts defined as I am still trying to get my head around the correct ones to use etc, but I have tried lots of different combinations to get this to work correctly with no success. Photo attached.

Any suggestions are greatly appreciated 🙂 TIA!

-Dan

1596599573-LS3.jpg

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charu
(@charu)
Active Member
Joined: 6 months ago
Posts: 10
August 5, 2020 9:42 am  

Hi, usually its a problem with contact or material model used. I have found some info online. This may help.

https://www.researchgate.net/post/How_to_fix_error_forrtl_severe_157_Program_Exception-access_violation_when_use_LS_DYNA_Solver_in_Ansys


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charu
(@charu)
Active Member
Joined: 6 months ago
Posts: 10
August 5, 2020 9:48 am  

also here is a good discussion on the same topic. you can use model checking tool in ls prepost to check if there is any error.

https://feassistant.com/forums/ls-dyna/what-may-be-the-cause-for-forrtl-severe-157-program-exception-access-violation-error-how-can-it-be-addressed/


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geardyn.1
(@geardyn-1)
Active Member
Joined: 10 months ago
Posts: 14
August 5, 2020 10:07 am  

try to use mortar contact. check your unit consistency system ...

use the latest version of the solver . 

recently our team had did a similar case study ( attached is a ex pic)

 

if ok, try sharing the key file , i shall try to replicate & debug the issue : to 

geardyn.1@gmail.com

1596618461-Helmet-model.jpg

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Negative Volume
(@negativevolume)
Reputable Member Admin
Joined: 2 years ago
Posts: 285
August 7, 2020 2:39 pm  

@dan-mnation

Very cool project. This seems to be one of the great mysteries of LS-Dyna. I think this type of error may only show up when using SMP, because I can’t recall anytime that I’ve seen this issue when using MPP. I know that you said you are relatively new to Dyna: SMP stands for Shared Memory Parallel Processing and MPP stands for Massively Parallel Processing. In a basic sense, SMP is used when running on a single computer, while MPP is used when running on a cluster of computers (kinda like a supercomputer).

I’m just bringing this up for anyone who is running into this problem as well.

But if you have to run SMP, your best bet is going to be checking through contacts and materials.


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Negative Volume
(@negativevolume)
Reputable Member Admin
Joined: 2 years ago
Posts: 285
August 7, 2020 2:43 pm  

Also, here was another brief topic on this:

https://feassistant.com/forums/ls-dyna/the-error-of-ls-dyna-cutting-simulation/#post-281


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