dr. mohammad taji - fragblast11€¦ · abstract 3 in this study, experimental tests on steel beam...

Dr. Mohammad Taji

24-26 August 2015 Sydney, Australia

In the Name of God

th International Symposium on Rock Fragmentation by Blasting

Content

• Introduction

• History

• Abstract of paper

• Practical Experiment of Blast Loading

• Numerical Simulation

• Output of simulation experiment

• Conclusion

2 th International Symposium on Rock Fragmentation by Blasting

Abstract

3

In this study, experimental tests on steel beam under blast loading, and

also numerical simulation by the AUTODYN software to analyze these

structures is discussed. Experiments on steel beam size of 12 by Emulite

explosive with 30 millimeters diameter and cortex is done.


Introduction

The analysis of constructs' elements against explosive loading is related

to the field of construct engineering and design engineering.

These analyses are done in the two stages of experiments and numerical

simulations with the help of related soft wares.


History

Katamaya and his colleagues (2007)

Balden and Nourik (2005)

5

Bonorchis and Nourik (2010)

Dehghan and Mohanty (2012)

Chung Kim Yuen and Nurick (1998)

Han Soo Kim (2013)


Practical Expriment of Blast Loading

6

Steel Beam Used:

A wide half-flange steel beam no. 12 was prepared with IPE – DIN 1025/5

standard & Steel S355

Fig 1. IPE standard in steel beam th International Symposium on Rock Fragmentation by Blasting


7

Table 1. Dimensions and weight of a half wide flange steel beam of size 12

Steel Beam Size

Hight

h(mm)

Flange width b

Web thickness

S

Flange thickness

t

cornersr curvature

radius

one meter wing weight G(Kg/M)

Nominal

Tolerances

Nominal

Tolerances

Nominal

Tolerances

Nominal

Tolerances

اNominal

Tolerances

12 120 2.0± 64 2.0± 4.4 0.5± 6.3 1.0± 4 10.4 6±



8

Explosive Used:

Emulite explosive (Emulsion With 4 to 6 percent aluminum powder )

with diameter 30 millimeter and Cortex.

Fig 2. Emulite 30mm and Cortex th International Symposium on Rock Fragmentation by Blasting


9

Table 2. Specifications of Emulite

Diameter Density Explosive Velocity Explosive Pressure Name

30mm 1.2g/cm3 5250m/s 9.12×106kpa Emulite



10

Fig 3. Placement of Emulite and cortex in steel beam 12



11 Fig 4. Effect of explosive loading on the steel beam 12


Effect of explosive loading on the steel beam 12

12

The resulting cut pattern in Emulite loaded site, a bend on beams'

flanges as well as a bend in the middle of beams indicate high

explosive power and pressure on contact surface. In order to examine

the resulting cut pattern, we repeated the experiment on five steel

beams no.12, 5 steel beams no.16 and five other steel beams no.18. The

same cut pattern was observed for all the beams


Numerical Simulation


Numerical Similation

14

Table 3. Coefficients of Emulite JWL equation of state

Parameters of JWL EO

1.2 (g/cm3 ) Density 2.4×108 (kPa ) A Parameter 4.6×106 (kPa ) B Parameter

5 (none ) R1 Parameter 1.45 (none ) R2 Parameter

4.25×103 (m/s ) Explosive Velocity

3.24×106 (kJ/m3 ) Energy unit volume

9.12×106 (kPa ) Pressure



15

Step 1. Material Definition: Steel S355



17

Linear Equation of State 7.8 (g/cm3 ) Reference density 1.77×108 (kPa ) Bulk Modulus 2.93 (K ) Reference Temperature Piecewise JC Strength 7.9×107 (kPa ) Shear Modulus 3.55×105 (kPa ) Yield Stress (zero plastic strain)

1.18×105 (none ) Eff. Plastic Strain #1 0.22 (none ) Eff. Plastic Strain #2 4.8×105 (kPa ) Yield Stress #1 6×105 (kPa ) Yield Stress #2

Table 7. Coefficients of the equation of state of steel S355



18

Step 2. Geometric Model: Emulite

Fig 6. Useless model of emulite



19

Fig 7. Emulite model used in simulation experiments



20

Fig 8. Geometric models of steel beam 12



21

Fig 9. Placement of emulite on steel beam size 12


Output of simulation experiment

22

Fig 10. Effect of explosive loading on steel beam 12 in the simulation tests at moment 3.5ms



23 Fig 11. Comparison of explosive loading on the beam size 12 in both experiment and simulation tests


24

Fig 12. Van mis stress distribution in steel beam size 12

351700KP

1243KP



25

Fig 13. Produced energy diagram in emulite versus time


26

Fig 14. Momentum in various parts of the steel beam size 12 versus time

Conclusion

27

In the present article, the effect of Emulate explosive loading was examined on

steel beam no.12. A numerical simulation and an experiment were done with the

help of AUTODYN software. The experiment was conducted on 5 steel beams.

Some other experiments were done on steel beam no. 16 and 18 for closer

examinations, but they're not explained here.


Conclusion

28

The following results were obtained:

● A similar cut pattern and bend on steel beams in both the experiment and

simulation. The effect of explosive loading on steel beams included a deep cut on the

surface of beams' web and bends on flanges. The length of cuts on steel beam's web

was approximately 124 and 200 millimeter on X axis in simulation and in the

experiment respectively.

● Emulite time- energy diagram indicates high energy of this explosive substance at

the very first moments (6.7×1011 uJ), suggesting high destructive power of high

explosive substances. th International Symposium on Rock Fragmentation by Blasting

Conclusion

29

● Color contours related to Von Mises Stress suggests strong stress imposed on

different parts of steel beams. Maximum stress at 0.66 ms is about 351700

kilopascal. This indicates high destructive power of high explosive substances.

● Time - momentum diagram shows the biggest momentum at early moments.

Therefore, we can conclude that there's a direct and one-way relationship

between the energy produced by emulite and the stress imposed on different

parts of steel beams and also between the momentum and stress imposed on

beams.


Conclusion

30

A comparison of patterns in the two experiments suggests a considerable

similarity between them. This similarity represents the precision of numerical

simulation and the reliability of AUTODYN. Of course, slight differences were

obvious in the two experiments including:

1) the percentage of coefficient errors related to the definition of substances

in simulation experiment such as errors in coefficients which are obtained

from state equation.

2) the differences between geometrical modeling of elements used in the

experiment and what is seen in the reality.

3) errors related to computer software analysis.

4) computer analysis power. th International Symposium on Rock Fragmentation by Blasting

Thanks for your attention


dr. mohammad taji - fragblast11€¦ · abstract 3 in this study, experimental tests on steel beam...

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