/DFS/WAV_SHA

Block Format Keyword Detonation times are computed taking into account an obstacle. The boundary of the obstacle is provided with an ordered group of nodes which defines the screen lines.


dfs_wav_sha
Figure 1.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/DFS/WAV_SHA/detline_ID/unit_ID
VDET YDET ZDET TDET mat_IDDET grnod_ID

Definition

Field Contents SI Unit Example
detline_ID Detonation Line identifier.

(Integer, maximum 10 digits)

  
unit_ID Unit Identifier

(Integer, maximum 10 digits)

  
VDET Optional: Detonation Velocity from detonation point. 8

(Real)

 [ m s ] MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaamWaaeaada Wcaaqaaiaab2gaaeaacaqGZbaaaaGaay5waiaaw2faaaaa@39DE@
YDET Y coordinate.

(Real)

 [ m ]
ZDET Z coordinate.

(Real)

 [ m ]
TDET Detonation time.

Default = 0.0 (Real)

 [ s ]
mat_IDDET Explosive material number concerned by detonation time.
= 0 (Default)
All /MAT/LAW5 (JWL) material law are affected by the detonation time.

(Integer)

  
grnod_ID Unsortable node group identifier. 1 2

Default = 0 (Integer)

  

Comments

  1. Node path must be provided in the correct order through an unsortable node group identifier (/GRNOD/NODENS). It defines the screen lines.
  2. Detonation times are available in the Starter output file (IPRI ≥ 3). Each element detonation time is computed at its centroid.
  3. Burn fractions are available in the time history file with /TH/BRIC card and BFRAC keyword.
  4. Detonation velocity is collected from the /MAT/LAW5 (JWL).
  5. Only compatible with 2D modeling.
  6. From an algorithm point of view, all points from the screen lines are considered as a potential detonation origin. The shortest detonation time is retained within all sources which have a direct path (if path from a potential source crosses any screen line then this source is ignored).


    Figure 2. Screen Lines are defined into an ordered group of nodes
    Detonation times are computed for each screen point by calculating the length of the path starting from detonation point.


    Figure 3.
    Screen points are considered as a potential detonation source (spherical). An arrival time is computed from each screen point, unless the direct path to the target point is intersected by a screen line.


    Figure 4.


    Figure 5. Shortest time is retained as the detonation time
  7. Detonation times for each element are then sent to the Engine as an initial condition. It may evolve with time due to rezoning (if unreacted explosive moves into the ALE grid or if the ALE grid used to model the unreacted explosive is moving).
  8. When a direct path exists from detonation point (element centroid or screen point), it is then lit using velocity VDET. Otherwise, detonation velocity is read form material with identifier mat_ID. This makes detonation of two adjacent explosives possible.


    Figure 6. Two adjacent explosive materials with two different detonation velocities


    Figure 7. Detonation times are computed with different detonation velocities in each side of the screen lines