Impact sensitivity of explosives

Correlations between the impact sensitivity of liquid hes and the maximum volumetric heat of explosion were obtained, allowing one to predict the sensitivity of liquid hes based on the physicochemical properties and element composition of hes. He friction sensitivity oblique impact sensitivity of. It started out with, can we take a common initiating explosive pentaerythritol tetranitrate petn and replace parts of it to change sensitivity properties, said explosives chemist virginia. A device for testing thermal impact sensitivity of high explosives. Spectroscopic determination of impact sensitivities of.

Ranking the dropweight impact sensitivity of common explosives. The overriding interest in this area has been the study of impact sensitivity. Shock sensitivity is a comparative measure of the sensitivity to sudden compression by impact or blast of an explosive chemical compound. During production, storage, transport, and similar activities, explosives are frequently exposed to various external stimuli such as friction, impact, heat, etc. The theory uses raman spectra of energetic materials to construct vibrational energy level diagrams, which are then used as input for a model designed to calculate the rate of energy transfer from phonon and nearphonon vibrational. Sensitivity of explosives to friction is one of the fundamental sensitivity parameters. For nto device 2 84%, it corresponds to the petn level. Impact sensitivity is one of the most important characteristics of energetic materials defining their safety in handling.

An experimental study has been made of the physical conditions which occur during the impact of solids on liquid explosives. Properties of energetic materials are characterised by a set of attributes and values which are necessary for the application and general safety of these materials. The journal of physical chemistry a 2011, 115 38, 1061010616. The aim of this agreement is to standardize test apparatus and test procedures for the determination of the impact sensitivity of explosives. Super impact stable tatb explosives recrystallized by. Static charge development and impact sensitivity of high. Crystal lattice free volume in a study of initiation. Primary explosives are extremely sensitive to mechanical shock, friction, and heat, to which they will respond by burning rapidly or detonating. The tex sensitivity to electrostatic spark was determined and tests for transportation were performed. Preparation and characterization of a new highperformance. Evaluation of material sensitivity over time does sensitivity increase or decrease. Sensitivity, stability and brisance are three of the most.

For classes of explosives with similar decomposition mechanisms, there appear to be statistically significant linear relationships sensitivity. Impact sensitivity test of liquid energetic materials a tiutiaev, a dolzhikov and i zverevarecent citations studies on cl20hmx 2. Explosives, impact sensitivity tests aim the aim of this agreement is to standardize test apparatus and test procedures for the determination of the impact sensitivity of explosives. Binary impact sensitive explosives chemistry apc forum. Common tatb explosive owns a low mechanical sensitivity with 50 j to impact and 360 n to friction. A large number of researches shown that the probability of explosion initiating of liquid explosives by impact depends on the chemical nature and the various external characteristics. Prediction of the impact sensitivity of aluminized. Impact sensitivity of liquid explosives springerlink. Abstract pressures generated on the explosive layer under conditions of experiments on the impact sensitivity of explosives have been calculated making use of the basic assumptions embodied in the hertz theory of impact, taking data from certain experiments on explosion. The ability of an explosive to react to these stimuli, resulting in either combustion or detonation, is defined as its sensitivity. In russia, the impact sensitivity of energetic materials and explosives is tested. For free running explosives, the density is often specified as the pounds of explosives per foot of charge length in a given size borehole. Impact sensitivities of organic high explosives are primarily functions of the rates of the thermal decomposition processes taking place in the temperature regimes generated under the impact hammer. The sensitivity of stacked small grains of the propellant to projectile impact was also determined.

Impact sensitivity of azide polymer composite propellants. In the 6080s, a great contribution to the studies on the explosive sensitivity and. Impact sensitivity test of liquid energetic materials. Oblique impact tests were performed on rx04ds and on the extrusion cast explosive rx08az. The sensitivity of explosives is controlled by factors that span from. Full text of impact sensitivity of primer explosives. Experimental methodologies and instruments that underlie the assessment of their production and handling safety have been described. On september 1, 1976, coburn filed a patent on the heat resistant explosive ammonium 2,4,5trinitroimidazole, atni for short. This report examines the drop weight impact test as it is currently used, describes its major flaw, and suggests an alternative test that holds the promise of.

The characteristic of an explosive is an attribute measured as a performance value after or during the chemical reaction. In this video, we will be making a impact sensitive explosive with an inexpensive household item. It was concluded that the velocity of detonation of epx2r was higher than the studied samples except composition c4, while its sensitivity is the lowest. Material sensitivity there are many uses for knowing the sensitivity of a material to impact, friction or electrostatic discharge esd. With an impact sensitivity of 50 centimeters, and a detonation velocity of 8,560 meters per second, atni has the power of rdx, but much better thermal stability. The data obtained from sensitivity tests play a fundamental role in decisions on the he applicability in general or any possible uses. Impact sensitivity of liquid explosives researchgate. Table 1 lowering impact sensitivity of tatb is still of vital importance for ihe. One step closer to understanding explosive sensitivity. There was no difference in the sensitivity to the card gap test between the azide polymer and htpb binder. Density is an important consideration when choosing an explosive. Shock wave high explosive explosive charge drop height impact sensitivity. Impact and friction sensitivity of energetic materials. It is shown that the lovax1a propellant is relatively insensitive to initiation compared to most cast explosives and propellants in use today.

We decided to evaluate the impact sensitivity of pure and asphaltcontaminated tnt through the application of the drop weight impact test and their shock sensitivity or explosionbyinfluence through the application of the card gap test, while differential scanning calorimetry was used for the evaluation of the thermal sensitivity. The critical initiating shock pressure and critical ignition energy are estimated. But the sensitivity of liquid explosive in the presence of gas bubbles increases many times as. Deltima precision provides a range of testing instruments for characteristics of energetic materials in research, production or quality inspection of finished products. The impact sensitivity of 58 liquid explosives hes and melts of solid hes were determined. In contrast, improvised explosives are designed to be easy to make and. Esd stationary electrode j data simulates in process conditions modified bureau of mines impact machine jm. Determination of the mechanical and thermal properties. Comparison of sensitivity of two materials to determine if one material could replace another in a particular process. In dependence on direction of the impact action on main crystal planes also sliding shear slide with fixed volume might have share in initiation.

The drop weight impact test is the simplest and easiest test that can be performed on small quantities of explosives or propellants, and yet it has only a minimal role in assessing explosive sensitivity or performance. Measurement of critical diameter, shock and impact. Impact sensitivity determines the minimum energy at which a falling weight will cause a sample explosive material under total confinement to react violently. Vertical drop tests were performed on 6 inchdiameter hemispheres of lx041. Statistical theory of initiation of explosives by impact. Although a considerable amount of experimental work has been done on the impact sensitivity of liquid explosives, the mechanism of initiation by mechanical shock is not fully understood. The friction energy played a more important role in the initiation than did the impact energy. Correlations between the impact sensitivity of liquid hes and the maximum volumetric heat of. It is shown that the high impact sensitivity of liquid or gelatinous explosives is due to the entrapping of minute gas spaces during the impact. Detonation velocity, detonation pressure, velocity of detonation formulae, shock sensitivity, laser initiation sensitivity, tnt equivalency, brisance, impact and friction are categorized as characteristics. I have been making binary exploding targets for long range rifle shoots. Quantum chemistry derived criteria for impact sensitivity.

My primary recipe is a mixture of blackhead, ammonium perchlorate and ammonium nitrate. This testing is typically done to discover potential handling problems for either. There are four devices used to measure impact sensitivity, l bureau of explosive apparatus boe, 2 bureau of mines apparatus bom, 3 picatinny arsenal apparatus pa, and 4 the explosive research laboratory apparatus erl. For classes of explosives with similar decomposition mechanisms, there appear to be statistically significant linear relationships.

When a given weight dropped onto an explosive charge, explosion or not is. So to test impact sensitivity of the spin states, they dropped weights on the material inside an anvil cell at. Currently, there have been a lot of impact sensitivity tests of he developed and used in many countries. A dropweight instrument is described to investigate the impact sensitivity of high explosives at elevated temperatures. Does anyone else have any experience making targets as such.

The use of increasingly less sensitive explosive materials to create an escalating chain reaction is known as an explosive train, initiation sequence, or firing train. Primary explosives form a group of explosives that are considered to be highly sensitive to some mechanical stimuli such as impact, friction, stab, heat, static electricity, flame etc. The use of the test apparatus and test procedures should facilitate the exchange and direct comparison of test data in conjunction with qualification testing according to stanag 4170. With few exceptions, denser explosives give higher detonation velocities and pressures. Sensitivity of explosives is the degree to which an explosive can be initiated by impact, heat, or friction. This paper presents new experimental method for sensitivity evaluation at the impact. The detonation of liquid explosives by gentle impact. Page 1 of 10 binary impact sensitive explosives posted in chemistry. Two theories of initiation by impact have been proposed to explore the mechanism. Switchable compound shows promise for safer explosives. Investigation of explosives mechanic impact sensitivity on.

The relationship of impact sensitivity with structure of. Sensitivity and performance properties of tex explosives. Performance and sensitivity of explosives request pdf. However, some studies have presented opposing results, showing that reducing the particle size increases the impact sensitivity 1014. Sensitivity of explosives sensitivity a physical characteristic of an explosive material classifying its ability to be initiated upon receiving ab external impulse such as impact, shock, flame, friction, or other influences that can cause explosive decomposition. In determining the uses of explosive materials and the necessary safe handling practices, many tests have been devised. Llnl smallscale drophammer impact sensitivity test. Hence, quantumbased reactive molecular dynamics simulations are potentially a tool for ranking the dropweight impact sensitivity and handling. The bam fall hammer also known as bam impact tester or drop hammer is designed to determine the sensitivity of high explosives, propellants, pyrotechnics and primary explosives to the impact stimuli of a fallen drop weight in accordance with the bam procedure. High explosives are conventionally subdivided into two explosives classes, differentiated by sensitivity. The literature indicates that impact sensitivities of organic high explosives are primarily a function of the rates of thermal decomposition processes occurring in the temperature 4j. A study of static charge development and impact sensitivity of high explosives was conducted. Key methods developed and used in the ussr and in the russian federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed. Bound explosives under nanosecond shock conditions.

On the shock sensitivity of explosive compounds with smallscale gap test. Research topics in explosives a look at explosives behaviors. The most important property of commercial he is their impact sensitivity. Determination of the shock sensitivity of a material intended for practical use is one important aspect of safety testing of explosives.

Impact sensitivity testers serves for measuring impact sensitivity of solid high explosives, propellants, pyrotechnics and also primary explosives. Sensitivity to friction for primary explosives sciencedirect. Relative sensitivity impact bureau of explosives cm modified type 12 impact cm rotter test 30 kg. Fallhammer m friction bam friction apparatus rotary friction test. A simple theory is developed which predicts impact sensitivities in crystalline explosives from vibrational spectra measured at room temperature. Material sensitivity safety management services, inc. Smallscale safety testing of explosives and other energetic materials is done to determine their sensitivity to various stimuli including friction, static spark, and impact. Examining the chemical and structural properties that influence the. Some sensitivity and performance properties of tex were studied experimentally and theoretically. Request pdf performance and sensitivity of explosives experimental data from. The piezoelectric coefficients, dielectric constants, capacitance per cubic centimeter, static electric fields, and youngs moduli were measured along axes perpendicular to the 110, 001, 100, 010, or 011 faces of single crystals of pentaerythritoltetranitrate 78115 petn. One of the most widely used tests for the determining the sensitivity of explosives is the impact test.