Rapid Fire and Blast Effects analysis

1. SIMPLIFIED FIRE AND BLAST EFFECTS ANALYSIS
INTRODUCTION
MCHTM Inc has developed a simple semi-automatic analysis system for early
evaluation of fire and blast effects on module structures. One fire and one
blast event are evaluated and reported herein with a relatively large HP
Compression module taken as the basis. Support of this effort by industry
colleagues is acknowledged here.
OBJECTIVES
Starting with a short duration accidental loading (eg blast, jet-fire) that causes
some primary structure to fail, assess whether there is (or is not) enough
reserve strength in a module to avoid total collapse.
LEVEL OF EFFORT – approx. 10 minutes per analysis iteration (plus computer
structural analysis run-time)
SUPPORTING 3rd PARTY SOFTWARE – At present, the system has been
implemented with (basic) SACS as the structural solver but could be adapted
to utilize other software that utilizes input and output files with known
format.
MCHTM Inc
EG. Hydrocarbon Explosion
EG (Jet) Fire
Impingement
Note: Explosion modelling with
overpressure radiating outward
from an assumed ignition point is
utilized. Further details available
upon request

2. PROGESSIVE COLLAPSE ANALYSIS
following a Blast Event
Hydrocarbon Blast in a Compression Module
– Single ignition point between 2nd & 3rd Deck
Levels
(Average overpressure = 0.7 bar)
“Failed” structure
after first analysis
iteration
“Failed” structure
after 6th analysis
iteration
Progressive Collapse History
Iter ID OO 8A 8B 8C 8D 8E
Iter Seq ID 1 2 3 4 5 6
#off 367 367 367 367 367 367
#off failures 69 63 69 71 74 74
#off deactiv 0 69 72 79 81 84
#off new failures
69 3 7 2 3 0
#off 108 108 108 108 108 108
#off failures 0 0 0 0 0 0
#off deactiv 0 0 0 0 0 0
#off new failures
0 0 0 0 0 0
MEMBERSPLATES
Note: “Failed” structure indicated
“Orange” (only members this scenario)
Conclusion:
Structure “holds” after this blast event ie
stabilizes after 74 member failures (and no
plate failures)
MCHTM Inc

3. MCHTM Inc
Jet Fire in a Compression Module with flames
impinging on a node in 2nd Deck Level (and
“failing” all structure connecting into it)
PROGESSIVE COLLAPSE ANALYSIS
following a Fire Event
Progressive Collapse History
Conclusion:
Structure is stable after this fire event – ie no
further “failures” after the assumed burn-
through of the initial 6 members and 4 plates.
“Failed” structure
before first
analysis iteration
“Failed” structure
after 3rd (and 1st
and 2nd) analysis
iteration
Note: “Failed” structure indicated “Orange”
(Both members & plates this scenario)
Iter ID OO 8A 8B 8C 8D 8E
Iter Seq ID 1 2 3 4 5 6
#off 367 367 367
#off failures 6 6 6 No change after
#off deactiv 10 6 6 1st Iteration
#off new failures 0 0 0
#off 108 108 108
#off failures 0 0 0 No change after
#off deactiv 4 0 0 1st Iteration
#off new failures 0 0 0
MEMBERSPLATES