User Manual

2DRing
analysis and incorporates a weighting factor which is a
function of the time a deck detonates and a rock mass
specific factor called "cooperation time".
As part of the 4D energy distribution analysis, a timing
simulation must be carried out first. The 4D energy
distribution tessellates points on a plane specified by the
user just like the 3D energy distribution. For each
calculation point, the nearest charged deck is found. The
time at which this deck detonates is used as a reference
time (t nd ). A weighting function is determined based on
the cooperation time and detonation time of charges. For
every explosive deck in the timing simulation the 3D
explosive energy value is calculated and multiplied by the
term given by the following weighting function:
e
t dt t nd
where t d is the time the deck detonated, t nd is the time the
nearest deck to the calculation point detonated and t c is the
co-operation time. The graph of this weighting function is
shown in Figure 3.3.
The cooperation time affects how steeply the weighting
goes to zero and is the time interval within which decks
adjacent to a detonating deck will assist in the
fragmentation of the rock mass. After this time interval, the
interaction of decks reduces significantly due to the
movement of the rock mass. The time is approximately the
time to first burden movement and is very much a rock
mass dependent property.
c
132 JKSimBlast