Computer simulation of explosive

Computer simulation of explosive fracture of rock can be carried out with finite difference stress wave propagation codes, such as the YAQUI code (2). YAQUI integrates in time the coupled partial differential equations for the conservation of mass, momentum, and energy. For a compressible fluid, these equations are... 

Hjertager, B. H., T. Solberg, and J. E. Fprrisdahl. 1991b. Computer simulation of the Piper Alpha gas explosion accident. ... 

Figure 4. Damage distribution and mean stress contour plot at 2.0 ms in computer simulation of Experiment 79S. The contour level and plot dimensions are the same as in Figure 1. At this time, a layer of spall damage can be seen near the free surface. It developed as the tensile relief wave propagated downward following the interaction of the explosively generated shock with the free surface. This figure shows the final computed damage distribution.

The computer simulation of the experiments in the frame work of two-phase single-velocity model [7] has been carried out in order to clear up the mechanism leading to the formation and irreversible development of the cavitation zone. The one-dimensional problem was solved in the cylindrical coordinate system ( T, 0,2 ). The impulsive energy release occurs in time moment t=0 along the axis Z. When t > 0 three areas are singled out in the problem are the explosive products (0 < p < ),... 

Numerical simulation of a complex dynamic fracture application can be illustrated by calculations of impact induced damage in a ceramic cylinder. The computer model used was originally developed for oil shale explosive fragmentation (Grady and Kipp, 1980), with various extended applications considered by Boade et al. (1981) and Chen et al. (1983). In this model, stress and strain are related through... 

In general, discontinuities constitute a problem for numerical methods. Numerical simulation of a blast flow field by conventional, finite-difference schemes results in a solution that becomes increasingly inaccurate. To overcome such problems and to achieve a proper description of gas dynamic discontinuities, extra computational effort is required. Two approaches to this problem are found in the literature on vapor cloud explosions. These approaches differ mainly in the way in which the extra computational effort is spent. 

Blast effects can be represented by a number of blast models. Generally, blast effects from vapor cloud explosions are directional. Such effects, however, cannot be modeled without conducting detailed numerical simulations of phenomena. If simplifying assumptions are made, that is, the idealized, symmetrical representation of blast effects, the computational burden is eased. An idealized gas-explosion blast model was generated by computation results are represented in Figure 4.24. Steady flame-speed gas explosions were numerically simulated with the BLAST-code (Van den Berg 1980), and their blast effects were calculated. 

Information gained from simulations can reveal key insights that explain gaps or contradictions in information. The time line is a useful tool in this development. For incidents of unexpected chemical reactions, it is common to attempt a lab scale simulation of the conditions involved in the exotherm or explosion. Many chemical processes can be modeled and duplicated dynamically by computer algorithms. Accelerated rate calorimeters (ARC) have proven to he highly useful tools for studying exothermic or overpressure runaway reactions. 

Availability of supercomputers and development of elegant molecular methods of dynamics simulation have been made a basis for the employment of explosive methods and a wide range of successful applications (Karplus and Petsko, 1990). The computer simulation produces individual particle motions as a function of time followed by the examination of specific contributions to the process. 

Chlipala, J.D., Scarfome, L.M., and Lu, C.Y. (1989) Computer-Simulated Explosion of Poly-Silicide Links in Laser-Programmable Redundancy for VLSI Memory Repair, IEEE Trans, on Electron Devices, Vol. 36, pp. 2433-... 

Large safety factors have been built into the design of the EDS vessel and the procedures for its operation. The mechanical integrity of the vessel was evaluated by Sandia National Laboratories using a combination of small-scale failure analysis tests and computer simulations. This evaluation indicated that the EDS-1 containment vessel could withstand several thousand detonations with more than 1 pound of explosive, providing a significant margin of safety for a system with an intended life of 500 detonations (SNL, 2000). 

The steps in assembling the computational tools needed to simulate the explosive fracture of oil shale have been described. The resulting code, with its input data, was then used to simulate three explosive field experiments. The results of the calculations are in good agreement with what actually occurred in the field. Further detailed comparisons are in progress for these experiments and the others that have been conducted. As this is done, improvements will be made in the input data and in the code physics. 

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