Friction-induced ignition modeling of energetic materials

Abstract

The heat released during the external frictional motion is a factor responsible for initiating energetic materials under all types of mechanical stimuli including impact, drop, or penetration. We model the friction-induced ignition of cyclotrimethylenetrinitramine (RDX), cyclotetramethylene-tetranitramine (HMX), and ammonium-perchlorate/ hydroxylterminated-polybutadiene (AP/HTPB) propellant using the BAM friction apparatus and one-dimensional time to explosion (ODTX) apparatus whose results are used to validate the friction ignition mechanism and the deflagration kinetics of energetic materials, respectively. A procedure to obtain the time-to-ignition for each energetic sample due to friction is outlined.

Cook-off test and numerical simulation of AP/HTPB composite solid propellant

“…(9). The physical properties and chemical reaction kinetic parameters from the references (Gwak et al, 2009;Kim et al, 2011) are listed in Tables 1 and 2.…”

“…The calculation model based on the above cook-off test is established by using the flowing simplified assumptions (Gwak et al, 2009): (a) AP/HTPB propellant is homogeneous and isotropic densification material, and approximately regarded as a two-dimensional axisymmetry unsteady heat conduction problem. (b) Physical properties of density, specific heat capacity and thermal conductivity as well as chemical reaction kinetic parameters are constant and cannot change with the temperature.…”

“…Chen et al (Chen et al, 2009) simulated the cook-off characteristics of TNT explosive at different heating rates. Additionally, Gwak et al (Gwak et al, 2009;Kim et al, 2011;Gillard and Longuet, 2013) also conducted corresponding numerical simulation analysis of cook-off process for several composite solid propellants. From the current research situation, the method of combining experimental analysis and numerical simulation to study the cook-off properties of energetic materials will be more comprehensive and through.…”

Surface Chemistry Dependence of Mechanochemical Reaction of Adsorbed Molecules—An Experimental Study on Tribopolymerization of α-Pinene on Metal, Metal Oxide, and Carbon Surfaces

“…Mechanochemistry refers to reactions activated by mechanical forces. − Compared to conventional thermochemistry, electrochemistry, and photochemistry where reactions are induced by heat, potential bias, or light irradiation, the molecular mechanisms or key parameters governing yield or selectivity of mechanochemical reactions are much less studied and understood. When a substantial amount of frictional heat is generated at high sliding speeds and not dissipated fast enough through conduction to the solid substrate, the thermal activations of interfacial molecules can be considered to play important roles. , When severe wear of solid materials occurs at high applied loads or under poorly lubricated conditions, then reactive surface sites such as dangling bonds or emission of charged particles (electrons or ions) or photons could be involved in the initiation of chemical reactions of molecules present on the wearing surface. − At a relatively low load and/or under slow sliding speed conditions, frictional heating and triboemissions are insignificant, but mechanochemical reactions can still take place. − …”

Investigation on the Friction Sensitivity of a Matchhead Composition Influenced by the Surface Roughness of Contact Materials

“…The parameters that influence flash temperature rise are vertical load, sliding speed, and surface roughness at contact. This flash temperature rise is likely to induce thermal expansion and runaway reaction of energetic mixtures in contact 13. Studies 7–12 on energy transfer between material contacts and surface roughness, the susceptibility of energetic mixtures to undergo explosion as a result of contact materials and their roughness are but a few.…”