hello
i am simulating an impact problem. when the part comes in contact, complete part is deleted or disappears. I have attahced the k file. Need help.
regards
Haris
Hi @harishameed,
It looks like your contact is *Contact_ERODING_surface_to_surface which is probably causing the issue. Is there a reason you are using the eroding part? If not, try *Contact_automatic_surface_to_surface
@negativevolume I tried using the *Contact_automatic_surface_to_surface but the result is same. there is no specific reason for selcting the *Contact_ERODING_surface_to_surface is because i am repeating this work published in an article and their this contact card was used. any other suggestion for it?
@harishameed okay I see. Did that work publish what control cards they were using by any chance? And how experienced are you using LS-Dyna if you don’t mind me asking?
@negativevolume no but they mentioned that this contact card was used. I am a student so learning LSdyna but I am aware of basics n ran simple cases already.
The screenshot of paper is attached for reference
@harishameed okay great to hear! We were all students at one time. They are using an eroding contact to represent the composite material being struck by a bullet. Did they provide the material properties of that composite? Between those and the lack on control cards would explain why you can’t get it to run
@negativevolume yes material properties are mentioned. I am attaching the reference paper. Thank you for your guidance.
@harishameed Unfortunately I’m on vacation without a computer so I won’t be able to help as much as I might normally be able to.
Double check that your units are consistent. I saw a pretty wildly high velocity which might make sense for a bullet. Maybe even reduce the velocity substantially and lengthen the simulation time to check that your model is working without that high energy impact. Also try some of these suggestions
https://www.researchgate.net/post/Can-anyone-help-with-problems-modeling-bullet-impact-with-LS-DYNA
Ballistics simulations sound cool and lure a lot of beginners to try to run, but they are not easy to debug due to the complex material models required and the amount of energy present in the impact.
@negativevolume thanks for your kind suggestions. I am following your comments and trying to simplify the problem and proceed step by step now.
@negativevolume Hello, Yes it is working now. The material properties in the reference paper were wrong. I first switched it to a simple material model (plastic kinematic) and then tweaked the materials model. Thanks for your concern and rememberance. Regards