Explosives Engineering Commons^™

Effect Of Explosive Charge Geometry On Shockwave Propagation, Catherine E. Johnson, Phillip R. Mulligan, Kelly Williams, Martin Langenderfer, Jeffrey Heniff

Mining Engineering Faculty Research & Creative Works

With advancements in the 3D printing of explosives, the understanding how the shape of an explosive charge influences the energy expansion and subsequently the focusing of energy is becoming increasingly more important. Theoretically, explosive charges could be printed to focus the energy on targets of interest or to synthesize nanomaterials. The first step to quantifying the energy expansion and shock wave convergences for a 3D printed charge is to examine simple geometries of traditional explosive charges (non-3D printed). Detonation of 15 PETN-based primasheet charges in the spherical, cubic, cylindrical, and tetrahedral configurations have been examined in this study. Qualitative data …

Shockwave Interaction With A Cylindrical Structure, Phillip R. Mulligan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

An increased understanding of the shockwave interaction with a cylindrical structure is the foundation for developing a method to explosively seal a pipe similar to the Deepwater Horizon accident in the Gulf of Mexico. Shockwave interactions with a cylindrical structure have been a reoccurring focus of energetics research. Some of the most notable contributions of non-destructive tests are described in ``The Effects of Nuclear Weapons'' (Glasstone, 1962). The work presented by Glasstone examines shockwave interaction from a 20-megaton bomb with a cylindrical structure. However, the data is limited to a peak overpressure of less than 25 psi, requiring several miles …

The Influence Of Caprock On Blast Fragmentation Distribution, Matthew Kurtis Coy

Doctoral Dissertations

"This dissertation describes the development of a small-scale model of a caprock-laden quarry blast and discusses the results from that testing. The purpose of this testing was to provide insight into the reasons for poor caprock breakage during blasting.

Small-scale test blocks were poured using a weak mortar mix to represent a limestone formation at a small scale. A cold joint was created in the upper portion of the test specimens to represent the bedding plane that separates caprock and substrate layers in a caprock-laden limestone bench. The scale-model test blocks were blasted using detonating cord. The primary configuration for …

Material Properties Affecting The Penetration Of Metal Targets By Copper Linear Shaped Charges, Kevin Lee Phelps

Masters Theses

"A linear shaped charge (LSC) is an explosive device used in demolition, aerospace, and in other applications that require the cutting of metal. Users of LSC's typically know the size of shaped charge needed to cut their target but commonly encounter previously untested materials. The motivation for this thesis is to provide an understanding as to what target material properties are good indicators of cutting performance so the selection of LSC can be more efficient. The author found that penetration theories for other types shaped charges were insufficient for the LSC, possibly because of the relatively slow projectile created by …

Modeling Explosive Lensing On A Cylindrical Body In Air: A First Step Towards Sealing An Underwater Offshore Oil Spill, Phillip R. Mulligan

Doctoral Dissertations

"In 2010, the British Petroleum (BP) Deepwater Horizon accident leaked oil into the Gulf of Mexico for 87 days. A fast response method that can seal an oil pipe and stop the release of oil is needed in order to prevent future oil leaks from turning into ecological and financial disasters. Explosives can serve this need.

This research examined how a circular implosive discontinuous explosive lens interacts with a cylindrical surface. The following research was designed to study the applicability of the Method this author developed to predict the peak pressure from multiple shockwaves converging on a centrally located cylinder. …

The Effects Of Physical Flash Hole Deviations On Factory-Grade Rifle Ammunition, Nicolaas Martin Schrier

Masters Theses

"The objective of this research is to determine the effect of dimensional and positional changes of the primer flash hole on the performance of factory-grade rifle ammunition. The studied variables were flash hole diameter, offset from center, and orientation of the offset in the primer pocket. Cartridge performance was quantified by measuring muzzle velocity, chamber pressure, and target grouping size (precision).

Five different flash hole diameters were tested for both the Remington .223 and Winchester .308 calibers: 1.4mm, 2.0mm (the Fiocchi standard), 2.4mm, 2.8mm, and 3.0mm. Each diameter was tested at three offsets: centered (no offset), 0.5mm from center, and …

Analysis Of Effects Of Surface Roughness And Local Surface Imperfections On Measured Pressure, Laurin Ashley Bookout

Doctoral Dissertations

"When tests using pressure to characterize the performance or effects of an explosive are conducted in laboratory or other small scale, highly controlled settings, it is expected that any gages will be ideally mounted and there will not be any surface imperfections or roughness near the gage location. However, when explosive tests are scaled up, the test beds typically do not have perfect surfaces. Instead there may be rough surfaces with various types of geometry or situations where it is extremely difficult to get the gage flush mounted with a flat surface. In a time where tests with multiple replications …

The Effects Of Short Delay Times On Rock Fragmentation In Bench Blasts, Margaret Ruth Hettinger

Masters Theses

"Optimized rock fragmentation is essential for minimizing downstream costs to mining operations. Photographic fragmentation analysis, vibration monitoring, and high-speed video all provide measurements of blast effectiveness and supply data that allows operations to modify blasts to achieve downstream goals.

This study evaluates the effects of short hole-to-hole delay times on rock fragmentation. Photographic fragmentation analysis and various delay times were used on the same bench blast, the effects of timing on fragmentation were determined. This analysis provides a representative understanding of timing effects on fragmentation in the field, different from previous blast models which either negate the effects of timing …

A Modified Initiation And Cut Profile Study Of The 10500 Grain Per Foot Linear Shaped Charge, Matthew Ortel

Masters Theses

"A 10,500 grain per foot (gr/ft.) linear shaped charge (LSC) was developed to cut targets that were too thick for smaller LSC. The manufacturer observed shallower penetration from the 10,500 gr/ft. LSC than was expected. This prompted investigations to uncover the cause of the perceived reduced performance.

A study performed at the Missouri University of Science and Technology changed the initiation method of the 10,500 gr/ft. charge to increase the cut performance of the charge. A modified two point, single end initiation method was devised and tested. This initiation method was termed "dual initiation" and focused on creating a planar …

Test Development To Determine The Feasibility Of Rubber Tractor Treads For Use As Blasting Mats, Matthew Kurtis Coy

Masters Theses

"The objective of this thesis was to determine if rubber tractor treads could be used as an alternative material for blasting mats. These treads are made from steel cable and vulcanized rubber and are very tough. However, once they reach the end of their life on mobile equipment, they are destined for a landfill, or dump site because they are too tough to recycle. A potential alternative use for them is as blasting mats.

An examination of existing mat designs was conducted to better understand the matting methods used by the blasting industry today, to learn from those designs allow …

The Effects Of Advanced Structural Materials To Mitigate Explosive And Impact Threats, Caleb Michael Baumgart

Masters Theses

"In a world of ever newer and modified improvised explosive devices (IEDs) that are very common in certain parts of the world, it is always more important to improve the devices used for protection. This research endeavors to design and analyze a blast barrier using three different media types to mitigate the high pressures from an IED or a car bomb. The three media types used in this research are pumice, steel grit, and foam. Six barriers were built to test the three media types and account for the changes from a standard solid concrete barrier to a barrier with …

Determining And Mitigating The Effects Of Firing A Linear Shaped Charge Under Water, Brian Burch

Masters Theses

"When fired under water, a Linear Shaped Charge (LSC) does not penetrate a steel target as well as in air. This lack of performance has been a problem for shaped charge manufacturers and their clients. It was obvious that this degradation of performance is due to water having a higher density than air and water being incompressible compared to air. This study aimed to better determine how the water was affecting the LSC and to provide a method of mitigation.

LSCs of different sizes were submerged under water and fired through the water with and without a target. It was …

An Analysis Of Burn Cut Pull Optimization Through Varying Relief Hole Depths, Michael Robert Allen

Masters Theses

"In underground blasting, the pull of the initial cut is the limiting factor for the success of the rest of the round. By improving the pull of the first cut, a critical step is made towards improving the entire round. This project attempted to optimize a burn cut's effective pull by varying the depths of the relief holes in the burn, and then analyzing the results. In testing, relief holes were drilled to depths both shorter and longer than that of the cut's charged holes. The overall objective was to consistently achieve greater pull than in a standard burn, using …

Explosively Formed Projectile Soft-Recovery Force Analysis, Laurin Bookout, Phillip R. Mulligan, Jason Baird

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The design of a soft-recovery system is critical to a researcher's ability to analyze hypervelocity projectiles. The researcher may decide to use one method over another based on several criteria, including whether or not non-deformed projectile measurements are required. This report analyzes the forces two different soft-recovery methods impart on the projectiles collected. Method 1 utilized three polyethylene water barrels placed “end-to-end” horizontally, providing 2.6 meters (9 feet) of water to stop the projectile. Method 2 is a modification of the soft-recovery method utilized in “Soft-Recovery of Explosively Formed Penetrators” by Lambert and Pope. This method utilizes a series of …

Note: Utilizing Pb(Zr 0.95ti 0.05)O₃ Ferroelectric Ceramics To Scale Down Autonomous Explosive-Driven Shock-Wave Ferroelectric Generators, S. I. Shkuratov, Jason Baird, E. F. Talantsev

Mining Engineering Faculty Research & Creative Works

Further miniaturization of recently designed autonomous ferroelectric generators (FEGs) S. I. Shkuratov, J. Baird, and E. F. Talantsev, Rev. Sci. Instrum. 82, 086107 (2011), which are based on the effect of explosive-shock-wave depolarization of poled ferroelectrics is achieved. The key miniaturization factor was the utilization of high-energy density Pb(Zr_0.95Ti_0.05)O₃ (PZT 955) ferroelectric ceramics as energy-carrying elements of FEGs instead of the previously used Pb(Zr_0.52Ti_0.48)O₃ (PZT 5248). A series of experiments demonstrated that FEGs based on smaller PZT 955 ferroelectric elements are capable of producing the same output voltage as those …

The Effects Of The Flyer Plate's Radius Of Curvature On The Performance Of An Explosively Formed Projectile, Phillip R. Mulligan, Jason Baird, Joshua Hoffman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

An explosively formed projectile (EFP) is known for its ability to penetrate vehicle armor effectively. Understanding how an EFP’s physical parameters affect its performance is crucial to development of armor capable of defeating such devices. The present study uses two flyer plate radii of curvature to identify the experimental effects of the flyer plate’s radius of curvature on the measured projectile velocity, depth of penetration, and projectile shape. The Gurney equation is an algebraic relationship for estimating the velocity imparted to a metal plate in contact with detonating explosives. The authors of this research used a form of the Gurney …

The Effects Of Water On Sympathetic Detonation And Dead Pressing Of Dynamite And Emulsions, Adam Michael Doerfler

Masters Theses

Dynamite and emulsions are very effective explosives in blasting; however they do have some shortcomings. Dynamite is prone to sympathetic detonation whereas emulsions are prone to dead pressing. While this does not happen all the time, the conditions in which the explosives are used do have an effect on whether or not they will sympathetically detonate or dead press.

Numerous researchers have investigated sympathetic detonation for a relationship between the distance between charges, hole separation distance, and size of explosive. This research aimed to look at how hole separation distance was affected when water was introduced into the boreholes for …

Pressed Powdered Titanium And Aluminum Conical Shaped Charge Penetration Of Geological Targets, Dominique John Nolan

Masters Theses

"Conical Shaped Charge penetration into rock is dependent on the physical characteristics of the rock itself and the design and composition of the shaped charge conducting the work. This study looks at the effects of a non-typical conical shaped charge and its penetration into four different rock targets. The shaped charge is made of a liner, which is not a typical solid but instead is a pressed powdered metallic compound of Titanium (Ti) and Aluminum (AI).

The study presents the raw data from testing against rock targets that range in density, uniaxial compressive strength (UCS), tensile strength, hardness scales, and …

The Effects Select Physical Parameters Have On An Explosively Formed Projectile's Performance, Phillip R. Mulligan

Masters Theses

"Identifying how changes in the physical parameters of an Explosively Formed Projectile (EFP) affect its performance is crucial in determining what physical parameters could be changed to achieve a desired performance. This research analyzes five of the physical parameters of an EFP, similar to an Iranian design (Worsey, 2009), and the effects on performance. The five physical parameters selected for this research were charge weight, confining geometry, flyer thickness, flyer curvature, and explosives-type. Eighteen different EFP designs were used to test the penetration, measured velocity, production of a dominant projectile, and kinetic energy of these five physical parameters. Of the …

Impact Effects Of Explosively Formed Projectiles On Normal And High Strength Concrete, Laurin Ashley Bookout

Masters Theses

"The ability to quickly estimate the damage that a projectile will do to a structure is highly desired for structures that will be required to resist threats of this nature. There are several formulas for concrete penetration due to projectile impact that are based on empirical data. However, there is a lack of publicly available data for projectile impacts with striking velocities that exceed 1 km/s and have weights greater than a few grams. This research is intended to expand the available data on explosively formed projectile impacts and determine which, if any, of the existing equations can be used …