The flying debris caused by damage to frangible structures can be a significant source of injuries in an explosion. Modelers can now utilize the HExFRAG module of BREEZE ExDAM to model these secondary injuries caused by fragmentation. HExFRAG uses the explosion modeling results from the HExDAM module to predict injuries caused by flying debris.
The HExFRAG module of BREEZE ExDAM was developed based on research conducted by the Department of Energy on fragmentation damage assessment. The graphical and tabular results generated by HExFRAG display predicted fragmentation effects, allowing users to analyze the injuries caused to people in the model by fragmentation. Using HExDAM with HExFRAG, users can identify which body component of each simulated person is exposed to fragmentation effects. This is very useful, for example, when studying the efficacy of blast shields and other objects designed to mitigate injury. Fragmentation scenarios (e.g., flying glass from a broken window) can be repeatedly analyzed after performing explosion model runs by assigning frangibility factors to structure components and placing people in various locations.
Entering Data into HExFRAG – Structures and People
HExFRAG only requires a few additional inputs after the explosion modeling scenario has been set up in BREEZE ExDAM HExDAM. The user will need to provide the following inputs for a HExFRAG fragmentation analysis:
- Number of floors
- Number of people
- Type of frangible material
The ExDAM HExFRAG module includes a number of preexisting standard materials, including:
- Aluminum Paneling
- Asbestos (Corrugated) Siding
- Brick Wall Panel, 8 or 12 In., Non-Reinforced
- Concrete or Cinder-Block Wall Panels, 8 or 12 In., Non-Reinforced
- Glass Windows, Large and Small
- Steel (Corrugated) Paneling
- Wood Siding Panels, Standard House Construction
Users have the ability to create a custom structure using the Edit User-Defined option in the HExFRAG Tab. To define a new structure, the user will need to enter the frangibility characteristics for the custom material (including the density, standard deviation, and initial fragmentation coefficient). Once a user-defined material is created, it will automatically display in the Frangible structure type field.
Graphical and Tabular Results
The predicted damage from the HExFRAG simulation can be viewed in the Graphical Results and the Tabular Results tab. Similar to HExDAM results, the HExFRAG graphical results include 2D/3D images of color-coded injury to personnel and spatial distributions of overpressure and dynamic-pressure/impulse using interactive contour planes, iso-surfaces, and volume rendering. Tabular results include the resulting injury due to fragmentation.