CRTI-06-0252RDProtocols for Modeling Explosive Threats in Urban Environments
R.C. Ripley, F. Zhang, D. Whitehouse, L. Donahue,K. Scherbatiuk, F.-S. Lien, P. Caron
CRTI Summer Symposium 2009, 15-16 June, Ottawa
Project Team
• Public Safety Canada (Lead Dept.):– Pierre Caron (PM), Tim Patraboy (DPM), Glenn Flood
• DRDC Suffield:– Fan Zhang (SA), Kevin Scherbatiuk (Structural)
• Martec Limited:– David Whitehouse (Protocols), Robert Ripley (Models & UE
Solutions), Laura Donahue, Eric Li (PV), Tim Dunbar (SV)• University of Waterloo:
– Prof. Fue-Sang Lien (Models), T. Xu, H. Ji• RCMP:
– Sgt. J.-Y. Vermette
Introduction
• Modeling is a key tool to support analysis of terrorist explosive threat impact on Canadian urban targets
• Need reliable approaches for generating and delivering information to decision makers
Blast Interaction Regimes
Suffield Scaled Urban StreetUnconfined Free-Field Blast
Urban Street Explosion
High Confinement
Train StationSubway
TunnelParkade
Simple Models are Not Always Sufficient
Oklahoma City (1995)
Moscow (1998)
Risk Management Series FEMA 426 (2003)
Urban Blast Modeling
High-fidelity, first-principles model
Capability and Knowledge Gaps
1. Fast and approximate modeling tools do not properly address near-field scenarios found in urban environments
2. Lack of physical models for non-ideal explosives in close proximity to urban structures
3. Lack of supporting documentation and corresponding guidelines for effective use of modeling tools
Objective of CRTI-06-0252RD
To develop protocols serving as standards and guidelines for modeling both ideal and non-ideal
explosive threats in close proximity to urban structures and environments
What are the Blast Modeling Protocols?
• Guidelines to be followed when performing/evaluating blast analyses for threats in urban environments
• A series of sequential steps which cover the blast analysis process
• Consider best-practice modeling while not restricting analyses to specific approaches
• A key feature is a set of baseline urban test cases – Database of accurate pre-computed urban scenarios
for quick analyses– Used to evaluate the range of applicability of any
blast modeling approach for a specific urban blast event
Project Roadmap
Eight Protocols Steps
Define and Interpret
Pre-Calculation Guidance
Calculation Steps
Analyze and Summarize
Who are the Protocols Users?
• Performers – Focus on performing and delivering results from a
specified blast analysis
• Consumers – Understand the context of blast problem which needs
to be solved– Provide advice to outside groups– Manage the resources on projects addressing security
issues, which may include the blast analysis
• Decision Makers – Take action based on the analysis results– Interested in how protocols reduce their risk
Pre-Calculated Scenario Matrix
• A total of 300 scenarios are planned
• Include range of targets and threats
Fundamental Urban Elements
U1: Straight Street
U3: Urban Bay U4: Urban Corner
U2: Single Building U5: Street Intersection
U6: Alley Intersection
Structural Elements
Classes of Explosives (Tentative)
1. HE (C4, TNT)2. Energetic Liquids (TATP etc.)3. Slurries (ANFO)4. Energetic Liquid/Metal Particles (NM/Al, Mg, Ti, Zr)5. Aluminized AN6. Organic Powder – Based Mixes (Corn Starch)7. Granular Explosive (pipe bombs)8. FAE (Liquid HC Fuel into Air)
Coordinated with CRTI-06-0204RD ‘Improvised Explosive Assessment’ and CRTI-07-0153RD ‘Transport of Combustible Liquids’
Preliminary User Survey Results
Type Rating (5 high)
ANFO 5.0
TNT 4.8
AN+other 4.8
Liquid Hydrocarbon 3.9
Liquid (NM, IPN) 3.3
Aluminized 3.1
TATP 3.0
Additional user surveys planned within the CRTI community
Description Rating (5 high)
4-Way Street Intersection 4.7
Parkade (small and large) 4.7
Straight Street 4
Internal Blast 3.8
Side-Street Alley 3.7
Urban Bay 3.6
Bridge Underpass 3.5
Tunnel Entrance 3.4
Single Building Façade 3.2
Bridge Tunnel 3.2
Blast Threats
Urban Environments
Blast Enhancement Table
# Walls 1 2 2 3 … 4 5 6
Elements →Free-Field
Single Building
Parkade Street … TunnelCourtyard/
MarketInterior RoomThreats ↓
TNT 1.0 6.0 10.0 11.0
C4 1.2 7.2 11.5 12.0
ANFO 0.8 4.5 7.8 8.4
Aluminized Explosive
1.5
FAE 10.0
…
Blast Enhancement Table
# Walls 1 2 2 3 … 4 5 6
Elements →Free-Field
Single Building
Parkade Street … TunnelCourtyard/
MarketInterior RoomThreats ↓
TNT 1.0 6.0 10.0 11.0
C4 1.2 7.2 11.5 12.0
ANFO 0.8 4.5 7.8 8.4
Aluminized Explosive
1.5
FAE 10.0
…
Physical Models
Required for simulating detonation and near-field blast from classes of conventional and non-ideal explosive threats, and their interaction with confined urban environments
Confined Explosive Afterburning
t = 5.7 ms
t = 10.7 ms
t = 20.7 ms
t = 50.7 ms
Donor Chamber
Acceptor Chamber
Confined Explosive Afterburning
Ea=120 kJ/mol
Ea=71 kJ/mol
Micrograph of particles
Unconfined Detonation
DDT process in a closed tube
Abrupt DDT
Aluminum Detonation in Air
Non-Ideal Explosive Analysis
Dense Multiphase Flow Mixing Models
• Particle jetting / wake and boundary layer interaction
pFr
, (drag)p xF
, (lift)p yF
D.L. Frost, MABS 19
Status and Plan
• FY08-09
– Physical models implemented (Del #3 and 4)
– Protocol prototype design complete (Del #5)
– First user meeting completed (users and scenarios)
• FY09-10
– Physical models validation underway
– Scenario calculations to begin after matrix finalization
– Protocol platform selection under review
– Additional user feedback meetings
– Protocol process requires testing and design iteration
• Final Protocols ~ June 2011
Questions?
Vulnerability Guidelines
FE M (low res) D E M S D O FS o/L
0.1 (near fie ld )
1 (m id fie ld )
10 (fa r fie ld )
h igh res FE M orana lytica l (perfect
so lu tion , assum e noerror)
%error
%error
%error
%error
err
or
tole
ran
ce
S o /L S o/L S o/L S o/L
valid
ra
ng
e
valid
ra
ng
e
valid
ra
ng
e
Combined Human Injury Chart
lines o
f equal td
upper range(destructive
timings)
lower range(constructive timings)
Structural Response for Non-Uniform and Complex Blast
Particle FragmentationDetonation Fragmentation
Impact Fragmentation
Reflection
Thermal Cracking
Aerodynamic Fragmentation
Wall Coating
Protocols Steps – Top Level
• There are 8 steps for performing blast analyses:
• Attributes
– Sequential
– Modular
– Reproducible
– Auditable
Define and Interpret
Pre-Calculation Guidance
Calculation Steps
Analyze and Summarize
Protocols Steps – Process Details