Kazisho The distances that these soil fragments travel are called the maximum ejecta radii. Write statements were inserted to print intermediate results. At the end of the test program, a full report of these results will be available. Stochastic Consideration of Cased Munitions for Casing Breakup and Airblast The buried explosion module BEM is a program designed to be used to calculate the residual velocity of fragments produced by a buried munition and the maximum ejecta radius of large soil chunks produced by the buried explosion. Due to calculation restraints division by the depth of burialif the depth of burial is zero the software assumes a depth of burial of 0. Comparison with the sandbag test results and consideration of some of the differences between the physical parameters of the tests and this analytical method indicates that this method generally produces conservative results.
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Search the history of over billion web pages on the Internet. To be consistent with the primary fragment calculations, the maximum range of the soil ejecta should be used. The question becomes how much soil does the fragment have to penetrate before escaping and what is the density of this soil?
However, it is not clear at this time for which portion of the burial depth this is true. Witness screens are used between sandbags to determine if fragments penetrate the sandbag layer and overpressure and noise measurements are taken at several distances from the center of the detonation.
USAESCH is involved in a test program to determine the thickness of sandbags necessary to defeat the primary fragments from a munition detonated on the ground surface. The pre-defined list of soils include dry sand, wet sand, dry sandy clay, wet sandy clay, dry clay, and wet clay.
The hazards to personnel and public that are of the most concern are overpressure noise and fragmentation. A munition is placed on its side on the ground surface and sandbags are placed around all four sides and the top of the munition with a 6- inch standoff from the munition. Also, where a crater is formed, the soil ejecta range is greater than the sandbag throw. A standard fragment is assumed. The soil slows down the fragments and, in some cases, may stop the fragments completely.
In most cases the explosion causes a crater. BEM does not include commands to view or print the results directly. Average soil properties are used for each of these soil types. In order to protect the disposal personnel as well as the public, a withdrawal distance from the detonation is enforced. Figure 1 — Maximum Ejecta Radii for Large Soil Chunks  Due to the nature of the equations used in BEM, the calculations will never result in a final fragment velocity and corresponding fragment range of zero.
If the depth of burial is zero surface burst the fragment does not pass through any soil and the velocity of the fragment is the initial velocity.
The results of the hand calculations and the BEM calculations are shown in Figures 2 and 3. Therefore, as a conservative estimate, all of the soil is assumed to have a density of one-half its undisturbed density for the purposes of calculating the drag coefficient on the fragment velocity.
The line shown in this figure has been specified by an equation and this equation has been included in BEM. The buried explosion module BEM is a program designed to be used to calculate the residual velocity of fragments produced by a buried munition and the maximum ejecta radius of large soil chunks produced by the buried explosion.
There was a problem providing the content you requested The results from these tests are compared to the results from BEM in Table 3. There is no added benefit to burying the munition any deeper until reaching the depth at which a camouflet is formed. The theory used in the development soe the BEM software will be discussed. The Structural Branch of the U. Therefore, dle is not full coupling between the explosive event and the sandbags whereas BEM assumes full coupling between the explosive event and the soil.
Soil from the crater is also thrown away from the center of the explosion becoming hazardous. At the end of the test program, a full report of these results will be available. These radii are shown in Figure 5. The theory used in BEM is discussed. If X is less than Y, a crater will be formed. For most unexploded ordnance the fragmentation range is much larger than the itc building distance IBD for overpressure. ABS Group Training Instructors Chris Leboeuf Some commonly found munitions have been analyzed and the explosive weight, initial velocity and maximum fragment weights are shown in Table 1.
Preliminary calculations for a variety of munitions show that by a distance of one foot from the center of the explosion, the fragment velocity is approximately twice that of the soil particles. If the energy release is relatively close to the surface, the cavity or void vents to the atmosphere and a crater is formed.
Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, de Washington Headquarters Services, Directorate for Information Operations and Reports, Jefferson Davis Highway, SuiteArlington VA Camouflet is formed 4. The user is prompted to input the following values. The input required for the software is detailed and two example problems are given.
Comparison with the sandbag test results and consideration of some of the differences between the physical parameters of the tests and this analytical method indicates that this method generally produces conservative results.
Is a crater or a camouflet formed? If the energy release is sufficiently deep below surface a void, called a camouflet, is formed. Also, BEM will never result in a zero fragment velocity and fragment range. The results from the BEM software for mitigation of primary fragments by tamped earth are compared to the results of the sandbag tests completed to date.
The burial depths determined using BEM are approximately twice the required thickness of sandbags from the sandbag tests. Toc BEM software produces the same results as when the method is applied by hand. Most Related.
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Maran Average soil properties are used for each of these soil types. The user is prompted to input the following values. A standard fragment is assumed. Write statements were inserted to print intermediate results.