ANFO Surface-Burst Blast Wave Properties Interface

The measurements from this explosion were chosen as the default values for the interface because of their uniformity when compared with those from several different agencies using a variety of measurement techniques. Excel© has been chosen as the interface platform because it is a component of most computer systems and has proved to be compatible with all operating systems as they have been upgraded over several decades.

Some of the functions used in the interface may not be included with all versions of Excel©, but if missing, they can be downloaded from Microsoft. ANFOSBI 1.0c consists of four spreadsheets. The first, Input Values, allows the user to input: the charge mass in kilograms; the ambient atmospheric pressure in kiloPascals, and the ambient temperature in Celsius.

The input values are used to calculate the Hopkinson (1915) and Sachs (1944), (Dewey 2000, 2016) scaling factors for radius and time. These scaling factors are used in the subsequent spreadsheets to determine the physical properties of the blast wave as functions of radial distance and time without further application by the user. The second spreadsheet, Peak Values, displays the physical properties immediately behind the primary shock at a series of radial distances from the centre of the blast wave defined by the input values.

The range of distances covers those for which reliable experimental measurements of the physical properties are available. The third spreadsheet, Time Histories, displays the physical properties of the blast wave at a series of times after the arrival of the primary shock at the radial distance input by the user. The integrals of the physical properties during their positive phases are also displayed.

The fourth and final spreadsheet, Wave Profiles, displays the physical properties of the blast wave at a series of radial distances behind the primary shock at the time after detonation input by the user. The integrals of the physical properties during their positive phases are also displayed. The spreadsheets can be downloaded as ANFOSBI 1.0c.xlsx and a Users’ Guide, ANFOSBI Users’ Guide.pdf, which describes the spreadsheets in more detail and how they may be used.

Similar interfaces have been published providing the physical properties of the blast waves produced by free-field TNT, Dewey (2021,2022a), surface-burst TNT, Dewey (2022b, c), and surface-burst propane/oxygen, Dewey (2018, 2019).