Tutorial Description:
A TNT bomb with a mass of 5Kg explodes in a 5×5×5m air domain. The S-ALE method in LS-DYNA is used to simulate this process and observe the blast pressure.
This case study uses LS-PrePost throughout the entire operation. The workflow is as follows.
I. Define Material Properties
Explosive Parameters:
Air Parameters:
Open LSPP, click on the right toolbar Model-KeyWord, and add the following keywords:
- *MAT_HIGH_EXPLOSIVE_BURN
- *EOS_JWL
- *MAT_NULL
- *EOS_POLYNOMIAL
Enter the keyword parameters based on the previous screenshots. The unit system is N-m-S.
II. Define Multi-Material Groups
Add the following keywords to define multi-material groups for air and explosive respectively:
- *ALE_STRUCTURED_MULTI-MATERIAL_GROUP
III. Create Air Domain
Using a 1/8 symmetric model, the final air domain size is 2.5×2.5×2.5m, with 100 divisions on each side.
Add the following keywords:
*ALE_STRUCTURED_MESH_CONTROL_POINTS, defined as follows:
*ALE_STRUCTURED_MESH
IV. Fill Bomb Region
A cube is used for simulation. Based on the bomb mass and density, the calculated cube size is 0.148m. Using 1/8 size modeling, the side length is 0.074m.
Add the following keywords:
*DEFINE_BOX, click Draw to display the approximate region for preview.
*ALE_STRUCTURED_MESH_VOLUME_FILLING
V. Add Boundary Conditions
Add symmetric boundary conditions on the symmetric plane and non-reflecting boundary conditions on the free surface.
Add keyword:
*BOUNDARY_SALE_MESH_FACE
VI. Add Detonation Point Settings
Keyword: *INITIAL_DETONATION
VII. Solver Settings
Add the following keywords respectively:
*CONTROL_ALE
*CONTROL_TERMINATION
*CONTROL_TIMESTEP
*DATABASE_BINARY_D3PLOT
Keep the rest as default. The final keyword items are as follows:
Submit for solution calculation.
VIII. Results Display
Blast pressure contour plots at different time instants are shown below:
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