• Explosives and Blasting
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• v.34 no.2
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• pp.31-38
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• 2016

The hydrodynamics code is a numerical tool developed for modeling high velocity impacts where the materials are assumed to behave like fluids. The hydrodynamics code is widely used for solving impact problems, such as rock blasting using explosives. For a realistic simulation of rock blasting, it is necessary to model explosives numerically so that the interaction problem between rock and explosives can be solved in a fully coupled manner. The equation of state of explosives, which describes the state of the material under given physical conditions, should be established. In this paper, we introduced the hydrodynamics code used for explosion process modeling, the equation of state of explosives, and the determination of associated parameters.

• Proceedings of the KSEE Conference
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• 2008.04a
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• pp.45-58
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• 2008

• Explosives and Blasting
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• v.21 no.4
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• pp.37-42
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• 2003

The source of rock breakage by explosive blasting is the energy released from an explosive. It is transmitted to the surrounding rock mass causing various types of fracture of rock material. The reaction of explosives and the resulting action on the surrounding rock mass are completed in very short tine, making it almost impossible to observe the processes occurring in the interior of the rock mass. In this study several input parameters are investigated by numerical modelling of blast source and dynamic response of rock mass. It is shown that damping coefficient and rising time are major parameters affecting dynamics response of rock mass.

• Explosives and Blasting
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• v.33 no.4
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• pp.7-13
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• 2015

Recently, as the demand for development and utilization of underground space is increasing worldwide, the blast damaged zone has become a major issue in constructing underground structures. In this study, to verify the explosion modelling method for blast-damaged zone (BDZ) around underground cavern, a series of small-scale test blasts was conducted using the concept of momentum trap. According to the test results, the input parameters to the numerical model (ANSYS LS-DYNA) were corrected. It is concluded that the suggested method of miniature blasting and numerical modelling using the MT concept well simulates the velocity of the MT projectile under given conditions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.462-468
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• 2017

KYP model is a pressure-based chemical kinetics that describes shock to detonation transition of energetic materials. In this research, the parameters of KYP model and JWL EOS for PETN-based explosive, namely PBXN-301, were determined. A series of unconfined rate stick tests and two dimensional hydrodynamic simulation were conducted to obtain the size effect behaviour of the explosive. As a result, it was confirmed that the parameters obtained from KYP modeling have more accuracy to predict the detonation velocities according to the inverse radius of PBXN-301 than the qualitatively obtained LLNL constitutive equations.

• Explosives and Blasting
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• v.22 no.4
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• pp.7-15
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• 2004

An explosion modeling technique was developed by using the spherical discrete element code, PFC3D, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a PFC3D particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). According to this concept, the explosion pressure is applied to the wall particles by the scheme of radius expansion/contraction of inner-hole particles. The output wall force is compared to the input hole pressure in every time step, and a correction routine is activated to control the radius multiplier of the inner-hole particles. A comparative blast simulation far a cement mortar block of $80\times90\times80mm$ was conducted by using the conventional explosion modeling method and the new one. The results of the simulation are presented in a qualitative fashion.

• Explosives and Blasting
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• v.23 no.1
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• pp.47-54
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• 2005

An explosion modeling technique was developed by using the spherical discrete element code, $PFC^{3D}$, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a $PFC^{3D}$ particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). A test blast was conducted for a RC column, whose dimension was $600\times300\times1800$ in millimeters. The initial velocities of the surface movements were measured to be in the range of $14\~18\;m/s$ with the initiation times of $1.5\~2.0m$. Then the blasting procedure was simulated by using the modeling technique. The particle assembly representing the concrete was made of cement mortar and coarse aggregates, whose mirco-properties were obtained from the calibration processes. As a result, the modeling technique developed in this study made it possible for the burden to move with the velocity of $17\~24\;m/s$, which are slightly higher values compared to those of the test blast.

• Explosives and Blasting
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• v.23 no.3
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• pp.27-42
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• 2005

An explosion modeling technique was developed by using the spherical discrete element code, $PFC^{3D}$, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a $PFC^{3D}$ particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). The stress wave propagation modeling was conducted by simulating the experimental approach based on the Hopkinson's effect combined with the spatting phenomenon that had previously been developed to determine the dynamic tensile strength of Inada granite. As a result, the stress wave velocity obtained by the proposed modeling technique was 4167 m/s, which is merely $3\%$ lower than the actual wave velocity of 4300 m/s for an Inada granite.

• Explosives and Blasting
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• v.32 no.2
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• pp.25-30
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• 2014

Although the construction noise and vibration are transient and intermittent, their impact on the surrounding environment is huge. Since the construction equipment noise and vibration is usually transmitted because of the long distance, the sound insulation and the proper design of anti-vibration measures are very difficult. The regulation requires that the noise and vibration caused by the construction equipments should be measured within 30m from the source, whereas the blasting noise and vibration should be measured at least 60m and 160m away from the source, respectively. Instead of the 2D modelling mainly conducted so far, the 3D analysis of noise and vibration with the consideration of the height and size of the building, mountains and hills in the vicinity of the source is necessary.

• Explosives and Blasting
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• v.35 no.1
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• pp.27-33
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• 2017

In this study, two fracture toughness test procedures are modelled for selected metal and rock on LS-DYNA, which is a commercial finite element code. The tests are conducted by using the 3-point bend test procedure for rectangular bar specimen. Because it takes a relatively long time to conduct the test, the implicit solver based on the Newmark method is adopted for the analyses. The values of stress intensity factor obtained from the analyses are 73 and $0.3MPa.m^{0.5}$ for the metal and rock material, respectively. It can be thought that the resulting small value of the fracture toughness of the rock material model well represents the brittleness of rock material.