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THE SUPPORT OF THE MINISTRY OF SCIENCE AND HIGHER EDUCATION UNDER THE GRANTS N519-419435 AND R00-0097-12 IS KINDLY ACKNOWLEDGED www.put.poznan.pl http://www.cmm.il.pw.edu.pl/
THE SUPPORT OF THE MINISTRY OF SCIENCE AND HIGHER EDUCATION UNDER THE GRANTSN519-419435 AND R00-0097-12 IS KINDLY ACKNOWLEDGED
www.put.poznan.pl
http://www.cmm.il.pw.edu.pl/
Outline:
- Motivation
- Introductory remarks
- Objectives and numerical analysis:
- Structural safety
- Public safety
- Results
- Conclusions
http://www.cmm.il.pw.edu.pl/
THE SUPPORT OF THE MINISTRY OF SCIENCE AND HIGHER EDUCATION UNDER THE GRANTSN519-419435 AND R00-0097-12 IS KINDLY ACKNOWLEDGED
Motivation:
The elements of critical infrastructure are often under explosive risk, and must be protected
- Airports
- Railway Stations
- Trade & Business centers
- Banks
- Fuel depots and storages
- Government agencies
Objective: Pressure distribution and structural damage
Introductory Remarks:
- The office structure (the main structure) is subjected to explosion
- The analysis demands a compelx caluculations (complexity, dof). This time the general problem of safety is uncoupled into three jobs:
A) STRUCTURAL ELEMENT SAFETY (steel column)
B) GLOBAL STRUCURE SAFETY (whole RC structure)
C) PERSONEL SAFETY (pressure evolution)
Introductory Remarks:
Structural safety criteria1. Acceleration for equipment3g, t > 1200s; 5g, t > 60s;8g, t > 10s; 18g, t > 0.2s;25g, t > 0.001s; 60g (database server)2. Stress & Strain for structural elementsDepending on material kind, compression, tension, strain rate, loading peaks and impulses
Public safety criteriaHuman tolerance to the blast output of an explosion is relatively high. However, the orientation of a person (standing, sitting, etc.) is really important. The pressure tolerance for short-duration blast loads is significantly higher than that for long-duration blast loads. There are used two separate criteria, in agreement US standard i.e. Unified Facilities Criteria (UFC 3-340-02), for assessment public safety.
1. Eardrums rupture for overpressure above 40 000 [Pa], and impulse duration 0.2 [Pa·s]2. Lung damage depends on overpressure-impulse and person weight
Objectives and Numerical Analysis: Structural safety
Case A – Steel column
Objective: To find a limit value of scaled distance (Z) for safety design
GeometrySteel column (H-section), IPE300, 3m high, fixed-joint boundariesMaterialJohnson-Cook model for stainless steel [Akbari, Joodaki 2005]
Numerical job72e3 S4R elements (0.005x0.005m2), time of the analysis is 52e3s (1CPU 2.6XEON)
1. Initial Static loading (10s)Dominant is vertical force (effort below 90%)2. Explosive loading CONWEP (0.01s)0.1kg of TNT in 0.25m distance3. Assessment of limit loading (10s)Upper boundary movement (1cm/10s)
54.01.0
25.0333
kgm
WLZ
F0 F0 F0
expl
osiv
e lo
adin
g
Δ
Objectives and Numerical Analysis: Structural safety
Case A – Steel column
Results IPE300
The results for the 1kg of TNT in 0.25m distance
The FE mesh is decreased in to 0.05 by 0.05 m2 element size
Objectives and Numerical Analysis: Structural safety
Case A – Steel column
Different failure criteria for steel elements
Objectives and Numerical Analysis: Structural safety
Case A – Steel column
Results IPE300 for close (distance <1m) explosions
The different high of the columns are analyzed, under different explosions (4x16 examples)
Zmin = 0.22 Zmin = 0.16
Limit vertical load must be lower than 90% of limit loading
Maximum support rotation for beams is 2 deg (TM5-1300)
Objectives and Numerical Analysis: Structural safety
Case A – Steel column
Results HEB600 for close explosions (distance <1m)
The different high of the columns are analyzed, under different explosions (3x19 examples)
Zmin = 0.14 Zmin = 0.17
Limit vertical load must be lower than 90% of limit loading
Maximum support rotation for beams is 2 deg
Objectives and Numerical Analysis: Structural safety
Case B – Whole structure
Objective: General assessment of whole structure safety
The explosive pressure is subjected to reinforced concrete structure. The homogenous RC material is loaded by the overpressure.GeometryRC structure 30x30m2 and 20m high (6 floors)MaterialElastic RC concrete with stress limit (FE deletion)Ideal Gas Equation of the state for the Ambient AirJWL Equation of the state for the ExplosiveNumerical jobEOS ~5e6 EC3D8 finite elements (0.2x0.2x0.2m3), Def. ~2e6 C3D8 finite elements (0.1x0.1x0.1m3)Time of the analysis is 26h (8CPU 2.6XEON)
1. Initial Static loading450kg/m2
2. Explosive loading CEL1000kg of TNT in 2.0m distance form the frontal facade
Objectives and Numerical Analysis: Structural safety
Case B – Whole structure
The results
FE failure criteria
Compression -80.0MPaTension +1.0MPa
t=0.001s after detonation
t= 0.01s after detonation
Objectives and Numerical Analysis: Structural safety
Case C – Public safety
Objective: Overpressure distribution inside a building
GeometryRigid geometry of the building simulates the reflection of the blast wave MaterialIdeal Gas Equation of the state for the Ambient AirJWL Equation of the state for the ExplosiveNumerical job~5e6 C3D8 finite elements (0.2x0.2x0.2m3), time of the analysis is 8h (8CPU 2.6XEON)
1. Initial Static loading450kg/m22. Explosive loading CEL100kg of TNT in 2.0m distance form the frontal facade
Objectives and Numerical Analysis: Structural safety
Case C – Public safety
The blast wave reflection from the rigid body
Objectives and Numerical Analysis: Structural safety
Case C – Public safety
Personnel safety criteria (TM5-1300, UFC), for SI units
Lung Damage Ear drums rupture
Objectives and Numerical Analysis: Structural safety
Case C – Public safety
Results The limit value for personnel safety has been set on 250000Pa (grey elements)The blast wave front (>150000Pa) propagates through the structure
Conclusions
A1. Limit values of scaled distance are obtained for steel columns
A2. Scaled distance is different for close and far field explosive action
A3. Further study enforces using of advanced material behavior
B1. Analysis of whole RC structure + steel reinforcement !
B2. Air discretisation vs. the results
C1. Personnel safety is analyzed, what about fragmentation ?
Thank you for your attention !
e-mail: [email protected] [email protected]
Poznan University of Technology
