Study on the Formation of Reactive Material Shaped Charge Jet by Trans-Scale Discretization Method

The formation process of reactive materials shaped charge is investigated by X-ray photographs and numerical simulation. In order to study the formation process, a trans-scale discretization method is proposed. A two-dimensional finite element model of shaped charge and reactive material liner is established and the jet formation process, granule size difference induced particle dispersion and granule distribution induced jet particle distribution are analyzed based on Autodyn-2D platform and Euler solver. The result shows that, under shock loading of shaped charge, the Al particle content decreases from the end to the tip of the jet, and increases as the particle size decreases. Besides, the quantity of Al particles at the bottom part of the liner has more prominent influence on the jet head density than that in the other parts, and the Al particle content in the high-speed section of jet shows inversely proportional relationship to the ratio of the particle quantity in the top area to that in the bottom area of liner.

Effect of fragment impact on shaped charge jet formation and penetration into steel target

Purpose This paper aims to investigate the effects of fragment impacts to shaped charge warheads in terms of shaped charge jet formation geometries and penetration performances. Design/methodology/approach In experimental process, a fragment was accelerated to a shaped charge warhead by means of a powder gun to a velocity more than 1,000 m/s, and this impact led to conical damage in the explosive of the warhead. Deformation on the warhead was visualized using X-ray technique to observe holes generated during fragment impact. Penetration test was performed against AISI 1040 steel plates with the damaged shaped charge warhead. Penetration performance of shaped charge jet, which deviated from the symmetry axis, was simulated by using SPEED software with 3-D Eulerian method to validate the numerical modelling method by comparing penetration test and simulation results of damaged warhead. Findings Simulation and test results showed good correlation for the warhead in terms of penetration depth and hole geometry at the impact surface of steel plates. In addition, the effects of the numbers and the geometries of fragment holes on shaped charge jet penetration performances were investigated with validated numerical methods. Simulation results showed that the increase in the number of fragment holes in the explosive of the warhead led to particulation of shaped charge jet that diminished penetration depth in the target plate. Additionally, simulation results also showed that the fragment hole geometry in the explosive after different fragment impact angles affected the amount of jet deviation from the symmetry axis as well as penetration depth in the target plate. Practical implications The results obtained from the current study revealed that fragment impact angle and different number of fragment impact reduced the penetration performance of shaped charge warhead by influencing the symmetry of shaped charge jet negatively. Originality/value The current study fulfils the need to investigate how fragment impact on the shaped charge warhead affect the formation symmetry of shaped charge jet as well as penetration performance by experimental and numerical methods. Penetration performance result of asymmetric jet is compared by experimental and numerical studies. A detailed methodology on numerically modelling of the effect of fragment impact angle and number of fragment impact on shaped charge jet performance is given in this study.

The Penetration–Explosion Effects of Differently Distributed Inactive/Active Composite Shaped Charge Jets

An analysis of the penetration–explosion (PE) effects of four distributions of inactive/active composite jets shows that a well-designed inactive/active double-layer liner can promote composite jet damage. Penetration experiments were then carried out for shaped charge jets having a single inactive (Cu) liner or an inactive/active (Cu/Al) double-layer liner with variable liner height. The behaviors and firelight patterns of the different jets were captured by high-speed photography. The perforation, deformation area, and deflection were measured for each plate, showing that the Cu/Al jets have stronger PE effects. Numerical simulation shows that the tip of the composite jet generated from the full-height liner is only Cu, whereas for the other jet, from the double-layer liner, Cu is almost wrapped entirely by Al.

Numerical Simulation of Rod Jet Formed by Shaped Charge under Rigid Constraint

In order to study the forming law of rod jet formed by shaped charge under rigid boundary constraint, ANSYS/LSDYNA finite element software is used to simulate the forming process of rod jet with ALE essential boundary, and the influence of structural parameters of shaped charge on rod jet forming is studied. The results show that compared with the free boundary constraint, the head velocity of rod jet increases by 63.5 % and the tail velocity increases by 59.3 % under the rigid boundary constraint. The head velocity and length-diameter ratio of rod jet decrease with the increase of the outside curvature radius of the liner, the thickness of the liner central position and the variable ratio of wall thickness. Furthermore, the tail velocity increases with the increase of the outside curvature radius of the liner, and decreases with the increase of the thickness of the liner central position and the variable ratio of wall thickness.

A Novel Shaped Charge Engineered from Nano-metallic Glass Composite / High Entropy Alloy Liner for Debris Free Perforation Tunnel with Improved Reservoir Conductivity Leading to Enhanced Production

There is an unmet need for a clean perforating tunnel, for deep-water natural completions that reduces fluid friction, providing better reservoir connectivity and thus enhanced production. As a disruptive innovator in the technology space, particularly in the energy sector, we have now bridged this technology gap through the synthesis of a novel alloy, which when cold isostatic pressed into a conical shaped charge liner enables a unique response. During the detonation event, the jet created from our novel degradable liner punctures the casing and progresses to penetrate the formation until an eventual collapse. Our novel material is designed such that, during detonation, reaction products, bulk metallic glasses (BMG) and/or high entropy alloys (HEA), are formed which disintegrate into a fine powdery debris in contact with water. These degradable BMG/HEA or complexions are preferentially segregated at interfaces with high free energy. They tend to decorate the grain boundaries and domain interfaces of the impermeable skin lining the crushed zone of the perforation tunnel as amorphous intergranular films (AIFs) and plug at end of the pathway. Interacting with flowback fluids the complexions promote grain dropping, disintegrating the liner and carrot leaving behind a clean perforation tunnel. As a result, it is projected that fracture conductivity is significantly improved, resulting in enhanced productivity. In addition, a clear perf-tunnel has zero skin value. As such, when compared to a coated tunnel with gun and charge debris, it needs little or no acid to clean-up. In addition, it is anticipated that this will reduce the formation breakdown and opening pressures offering improved economics for the client. Last but not least, this leads to cost reduction of authorized field expenditure (AFE) to support optimized performance of completion designs allowing for increased production. The additional novelty of our liner designed through powder metallurgy (PM) techniques is a sub-sonic deflagration of the jet, during its collapse, resulting in sputtering of complexions and BMG/HEA residue along the perforation tunnel. These sputter-deposited jet complexions react with fluids during flowback, selectively being etched, barely needing water for the clean-up. The disintegration of this skin and slug, if any, in the perf-tunnel into fine particulates, subsequently being removed, leaves behind a clear, clean tunnel. CLEAR shaped charges have now been qualified to customer specifications in field conditions and are ready to be commercialized. Our journey of innovation does not end here. In fact, this is not even the beginning of the end, but it is, perhaps, the end of the beginning. To offset our carbon footprint and having embraced environmental and natural resources stewardship as one of our core values we are committed to contributing, as individuals and as an organization, to a flourishing human-ecological system. Through technology synthesis we have developed the concept of engineering seedpods for sustainable reforestation and Agri-tech. This had led to an endeavor for rapid tree planting through areal drones and UAVs’ to offset the effects of deforestation caused by human activities and natural disasters. In our paper we will additionally highlight this innovative technology cross-pollination and our efforts in low carbon and ESG endeavors.

Comparison of Shaped Charge Jet Performance Generated by Machined and Additively Manufactured CuSn10 Liners

The Selective Laser Melting (SLM) technique has attracted attention in a wide range of manufacturing research areas, including the defense industry because of its high efficiency and good consistency of manufactured material properties. Shaped charge liner is the crucial unit in the shaped charge warhead. However, jet performance formed by SLM-produced liner remains to be studied systematically. In the present research work, the SLM technique was applied to manufacture CuSn10 shaped charge liners. Casted CuSn10 liners were also fabricated using the classical turning method for comparison. The grain size of the SLM-produced liner was found to be much smaller than the machined liner due to the rapid heating and cooling rate during the SLM manufacturing process. This contributed to improved jet performance. A flash X-ray photography system was applied to capture jet stretching appearances. Necking appears at the jet tip formed by the machined liner, while the jet formed by the SLM-produced liner remains continuous. Penetration test results show that the penetration depth of the jet formed by the SLM-produced liner is around 27% larger than that formed by the machined liner. Segments along the sidewall of the penetration tunnels were selected for in-depth micro analysis. Energy dispersed spectrum (EDS) surface scanning results indicate the composition at the side wall of the penetrated tunnel. Metallurgical microscope was applied to distinguish four different phase zones of the target. The width of these different zones indicates the severity of the lateral interaction between the jet and target, which can be adopted to evaluate jet penetration capability. The present study analyzes the factors that influence jet performances and proves that SLM technology is well-adapted in the manufacturing of shaped charge liners.

Study on Penetration Performance of Rear Shaped Charge Warhead

In guided munitions, the shaped charge jet (SCJ) warhead is located behind the simulation compartment (including the control cabin, the steering gear cabin, and the guidance cabin). Therefore, the order of penetration of the SCJ is the simulation cabin and the target. To study the penetration performance of the SCJ to the target plate, the numerical simulation method is used to study the penetration performance of the designed warhead for the steel target at different standoffs, and the depth of penetration (DOP) at the best standoff is obtained, that is, the DOP of the steel target is about 128 mm. Additionally, the penetration performance of the SCJ warhead to target is studied by numerical simulation and experimental verification. Numerical simulation and experimental results show that the DOP of the SCJ warhead to the steel target is 50 mm without the simulation cabin, and about 30 mm with the simulation cabin. The results show that the penetration performance of SCJ is greatly weakened under the condition of non-optimal standoff, but the rear shaped charge warhead still has a strong penetration performance after completing the penetration of the simulated cabin.