LS Dyna

LS Dyna

Modeling blast wave propagation in a complex tunnel in Autodyn

    • shin3
      Subscriber

      Hello everyone,

      For modeling an explosion inside a tunnel in Autodyn, the air is often modeled in a 3D domain using the Euler-FCT solver. The problem is that the air mesh should be generated only using the "box" geometry. The shape of my tunnel is not straight but has many curved parts. Consequently, the number of unused elements would become quite larger than that of used ones, which would significantly increase the computational expense. Moreover, it is almost impossible to set the unused elements to be void using the option, "Unused", due to the complex geometry of the tunnel. 

      Could you guide how I can model the air part that fits inside the tunnel? It would be the best if the air could be modeled similar to a dome shape inside the tunnel. Please let me know if there is a way to model an air mesh in Autodyn with a curved or beveled shape or if there is another modeling strategy to simulate an internal explosion of tunnel. 

      Below are tunnel samples similar to that I need to model in Autodyn.

      Thank you in advance,

    • Karthik R
      Administrator
      Hi, nWhat is the nature of the application you are intending to model? Could you please help us understand?nThanks.nKarthikn
    • shin3
      Subscriber
      Dear Karthik,nThe goal of this simulation is to predict blast pressures inside a tunnel using Autodyn when high explosives detonate at the entrance of the tunnel and the blast waves propagate inside it. I am looking for a modeling technique to generate an air mesh that fits the tunnel well. Did I understand your question correctly?nThank you,nShinn
    • Karthik R
      Administrator
      Hi,nThank you for helping us understand the application. This is what I'm trying to understand - is your application ITAR? If yes, you should not be posting these details on a public forum. Could you please confirm this?nThanks.nKarthikn
    • shin3
      Subscriber
      Hello,nNo, this study has absolutely nothing to do with ITAR.nThank you,nShinn
    • Missy Ji
      Ansys Employee
      You would need to use Autodyn GUI, which would be more flexible in creating Euler part and unused cells. Workbench GUI will only give you a box for Euler domain.n
    • shin3
      Subscriber
      Hello mji,nThank you for your answer. nI already tried the Autodyn GUI, which also give me only a box for Euler parts. Although the unused cell option can be used in it, it is almost impossible to creat the Euler grids along the complicated tunnel. nPlease let me know if it is really possible with the Autodyn GUI. nThank you,nShinn
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