Brady Aydelotte

• Doctor of Philosophy
• Engineer at Idaho National Laboratory

Boron carbide is a ceramic of great interest due to its high strength, low density, high hardness, and of course, its tendency to undergo amorphization during failure. Commercial boron carbide commonly contains a variety of defects including pores, carbon inclusions, and aluminum nitride and boron nitride inclusions, but what role do the defects pl...

We conducted simplified long rod impact experiments which were instrumented with flash X-ray and Photon Doppler Velocimetry (PDV). The time resolved experimental data was used to fit a geomaterials model using both 2D and 3D simulations. It was found that the 2D simulations could not fit the experimental data satisfactorily. The 3D simulations were...

Brittle materials such as ceramics and oxide glasses are widely employed because they possess a variety of useful properties including hardness, strength, wear resistance and/or transparency. Normal and oblique impacts of spherical projectiles on brittle materials are similar to the classical Hertzian sphere indentation problem, yet different in si...

This chapter examines how ballistic impacts on ceramics generate different types of damage including varying levels of comminution, cone cracking, and radial cracking through experiments on fused silica glass targets. The chapter shows how measurements of the fracture cone angle on a plane perpendicular to the plane containing the shot-line vector...

Time-resolved terminal ballistic experiments were performed to examine the crack formation and progression in glass materials due to rod impact. Damage evolution in glass was quantified at a range of striking velocities and target obliquities. It was found that minimal obliquity resulted in significant rotation of the cone relative to the surface n...

The initiation of aluminized fluorinated acrylic (AlFA) nanocomposites during modified Taylor impact tests was investigated. Samples were impacted against a steel or sapphire anvil at a nominal velocity of 150 m/s. A framing camera was used to capture head-on and side-profile impact images for the sapphire window and steel plate rigid anvils, respe...

Ceramics undergo a complex failure process when subjected to impact by a projectile. Projectile impacts on thick ceramic targets produce varying levels of comminution, cone cracking, and radial cracking. Sphere impacts result in limited penetration and comminution relative to projectiles with a longer aspect ratio, yet significant radial and cone c...

The phenomenon of dwell during projectile impact on ceramics has been an active area of research for several decades. Dwell in confined ceramics has received much attention, particularly the role of cover plates and their influence over the dwell to penetration transition. Dwell during long rod impact on unconfined ceramics has received relatively...

We present a methodology for concurrent Photon Doppler Velocimetry (PDV) and in-situ flash X-ray imaging during ballistic impact of metallic penetrators into monolithic armor grade ceramic targets. Tungsten heavy alloy long rod penetrators were launched from a smooth bore cannon into silicon carbide targets at velocities of 0.753 and 1.403 mm/μs. P...

A series of experiments were performed to probe the tensile behaviour of a cold sprayed reactive metal composite material containing a mixture of nickel and aluminium. Data were acquired at two different strain rates and were collected using high speed photography, strain gauges, force-extension measurements and were analysed using digital image co...

Fragmentation results for structural energetic materials based on intermetallic forming mixtures are reviewed and the implications of the fragment populations are discussed. Cold sprayed Ni+Al and explosively compacted mixtures of Ni+Al+W and Ni+Al+W+Zr powders were fabricated into ring shaped samples and explosively fragmented. Ring velocity was m...

The mechanisms influencing impact initiation of reactions in structural energetic materials formed by explosive compaction of pure Ni, Ta, or W powders mixed with Al powder are investigated in this work. High speed images of rod-on-anvil impact tests indicate that the energy requirements for initiating reaction in Ta+Al compacts are lower than thos...

A comparison of different Ni+Al reactive materials is conducted to elucidate the effects of microstructure morphology on performance. CTH, a multi-material Eulerian hydrocode, was utilized to study mesoscale deformation during simulated rod-on-anvil experiments. It is found that the cold sprayed Ni+Al, which has a more topologically connected nicke...

Some recent results from a project examining the use of novel energetic materials for structural components are presented. The aim of the research is to gain understanding as to how compressed metal powders could potentially boost performance in munitions cas-ings. Specifically the experiments concerned involve loading rings of pressed tungsten-alu...

A study of fragmentation behavior of a Ni-Al structural energetic material was undertaken to determine fragment size and distribution as well as study the impact of material microstructure on the fragmentation process. Rings were fabricated from a nearly 100% TMD Ni-Al structural energetic material and subjected to explosive fragmentation experimen...

The mechanisms of combustion reaction occurring under impact loading of aluminum powder compacts are studied using UV/Vis spectroscopy to gain time-resolved chemical information. Impact experiments performed on aluminum powder compacts reveal light emission due to reaction at velocities greater than 400m/s in air, while no reaction is observed in a...

A series of experiments were conducted on explosively loaded rings for the purpose of studying fragmentation. In addition to the collection of fragments for analysis, the radial velocity of the expanding ring was measured with PDV and the arrangement was imaged using a high speed camera. Both the ring material and the material used as the explosive...

A double-tube implosion geometry is used to explosively shock consolidate intermetallic-forming Ni-Al, Ta-Al, Nb-Al, Mo-Al and W-Al powder mixtures for fabricating bulk structural energetic materials, with mechanical strength and ability to undergo impact-initiated exothermic reactions. The compacts are characterized based on uniformity of micro st...

A new theory for processing polycrystalline materials by rotation and lamination is presented. The processing is realized by ultrasonic consolidation that can achieve welded interfaces with minimal (and in some respects, negligible) disturbance of the microstructure due to plastic deformation. Evidence of minimal plastic disturbance is presented fo...

The quality of ultrasonically consolidated parts critically depends on the bond quality between individual metal foils. This necessitates a detailed understanding of interface microstructures and ultrasonic bonding mechanism. There is a lack of information on interface microstructures in ultrasonically consolidated parts as well as a lack of consen...