LS-DYNA Blast Analysis Incorrect Deformation

Hello everyone,

I am trying to model a blast at the center of a hollow cylinder. However when I run the simulation it seems to be that the deformation is inverted, sucking in the cylinder instead of expanding it outwards. The deformation should be going outwards but instead does the opposite. When I move the explosion onto the outside of the cylinder, it displays what I would think is the correct deformation and caves in the cylinder.

I think it must be something wrong with some keywords maybe MAT or LOAD or SECTION (Integration method). Please also let me know if anyone has experienced this and knows what the issue is? Attached below is a picture of the pre-post if that is of any help.

Kind regards,

Joseph Roxburgh


  • AniketAniket Posts: 1,235Ansys Employee

    Ansys staff can not download any files on the forum, so if you want to reach a larger audience to get answers from, please insert inline images describing your problem.


    How to access Ansys help links

    Guidelines for Posting on Ansys Learning Forum

  • tslaviktslavik Posts: 9Member
    edited March 19

    If you are using *LOAD_BLAST or *LOAD_BLAST_ENHANCED please assure the segment normals point toward the charge. For example, Remark #2 for *LOAD_BLAST states:

    Orientation. The target’s segments must be consistently oriented so that the normal vector of the portion of the target having a direct line of sight to the blast points roughly towards the blast. For example, segments defining a structure being blasted from the outside should have outwardly oriented normal vectors, whereas a cavity containing a blast should have inwardly facing normal vectors. 

Sign In or Register to comment.