Director:  Harland

A shaped charge uses high explosives to form a metallic liner into a high velocity jet of molten metal. The velocity gradients in the jet cause it to stretch several times it original length with tip velocities that can greatly exceed 8 kilometers per second. At late times the jet fragments into small pieces. Applications of shape charges include both military and industrial uses. On the military side, conical shaped charges, which be modeled in two dimensions using axisymmetric elements, can effectively penetrate armor, and linear shaped charges, which can be modeled in two dimensions using plane strain elements, are used to separate the stages in multistage rockets. On the industrial side, oil companies commonly use shaped charges for wellbore perforation.

In LS-DYNA shaped charges can be easily and accurately modeled. A unique feature of LS-DYNA is its ability to use adaptive remeshing to quickly compute the jet formation using just minutes of CPU time. The adaptive remeshing is completely automatic and requires no interaction by the user. Automatic contact finds all the interactions between different parts and accurately treats the interfaces. Two shaped charges illustrate this capability.  The first is a linear charge used in rockets in the aerospace industry (AVI #63). 


Linear Shape Charge AVI Library #63 (9.4MB)

The second is the "standard" 81mm BRL shaped charge with a conical liner.

 81 mm BRL shaped charge AVI Library # 64 (1.06MB)

 In the latter calculation adaptive remeshing is used each microsecond and the calculation is carried out to 50 microseconds. The last animation shows a close-up of the adaptive remeshing.

  
AVI Library 65    (339KB)  

AVI Library 66 (1.24MB)

AVI Library 67 shows a shallow shape charge simulation where adaptivity is used to run the calculation to late times.


AVI Library 67 (707KB)

 

In LS-DYNA shaped charges can be easily and accurately modeled. A unique feature of LS-DYNA is its ability to use adaptive remeshing. 

For Information/Questions regarding this site or Warhead Analysis contact Harland at feaanswer@aol.com