Scientists from South Ural State University have patented a program for determining the conditions of explosives ignition in case of mechanical loads. The developed software package will help quickly assess at which conditions a material can explode, in order to enhance the control over the movement of such materials.
The researchers have studied the mechanisms that could potentially lead to detonation of explosive substances during their transportation, handling and storing in warehouses. By artificially initiating physical effects (for instance, shocks or friction), the scientists are searching for the ways to neutralize the explosion hazards for high-energy substances.
“We have developed a software package in order to study the friction mechanism of emerging of the material’s zones of local heating, that is, to examine the influence of friction occurring on the boundary of contact between the iron projectile and the energetic material,” shares Evgeny Pomykalov, senior lecturer at the SUSU Department of Computational Mechanics. “Namely the friction mechanism is among those few that can lead to an explosion in case of low-speed mechanical impacts. In essence, our software package simulates the behaviour of an explosive substance as a result of such an impact. Using numerical modelling, we can calculate the local hotspots that emerge when the spherical projectile penetrates into the energetic material at the loading rates of less than 30 m/s; these are the exact conditions when an explosion could theoretically be initiated.”
The unique mathematical model takes into consideration the friction force and heat fluxes, which propagate both in the energetic material and in the iron projectile. After full-scale experiments, the scientists were able to calculate the distribution of temperature in the thin contact layer, and this allowed to evaluate the explosive ignition delay (that is, time) in case of friction.
The patented software was tested on full-scale experiment releases that confirmed its efficiency and computational accuracy.
The distinguishing feature of this software package, developed using the FORTRAN language, is that the mathematical model is based on the laws of continuum mechanics, where the equation of motion of the projectile and the equation of motion of the energetic material are solved simultaneously.
The system allows to calculate the thermodynamic parameters of the material under study, as well as the deformation rate, temperature, etc., on the contact boundary, and even to determine the geometry of the deformed energetic material depending on the conditions of percussion.
By only performing a computer-aided calculation, it becomes possible to quickly assess at which conditions an object can explode, in order to enhance the control over its movement. This development by the scientists from Chelyabinsk can be used at enterprises dealing with storing and handling various high-energy substances, as well as for their transportation.