Blast Effects Research Articles

Optimization of high performance hybrid composite under ballistic test and performance of the hybrid composite under IED blast

Abstract In this investigation a novel material has been developed comprising of Silicon Carbide (ceramic), Aluminium honeycomb (metal) and Poly Ether Ketone (PEK)—Poly Phynelene Benzobisoxaole (PBO) fiber based blast proof composite. The experimental results proved that this polymeric composite is highly suitable for 9 mm pistol bullet with 430 m s−1 at distance of 5 m as well as for improvised explosive devices blast to absorb the sharpnels/splinters. This investigation also highlights an efficient back layer for a blast-proof sandwich composite. Layer optimization was carried out by finite element method (FEM) analysis of blast effect on the multi-layer polymer composite panel by ANSYS Explicit Dynamics (LS DYNA Solver). The resultant optimal layers of PEK-PBO composites then tested to validate results of FEM analysis. Experimentally it is proved that polymeric composite with 10 layers of PBO fabric when test fired under 9 mm pistol bullet with 430 m s–1 at distance of 5 m, the bullet penetrates, however, when the polymeric composite is made with a total of 20 layers of PEK-PBO fabric, all the test fired bullets are stopped. Therefore, under SNANAG 4569 blast test, the polymeric composite was essentially made with 20 layers of PBO fabric and it is experimentally proved that PEK-PBO composite is highly efficient as the back layer of hybrid composite and all the sharpnels of IED blast are completely absorbed.

Structural response of steel-concrete composite panels to near field simultaneous blast and fragmentation loading

Steel-concrete composite sandwich panels are used in blast doors or blast walls to protect personnel and equipment in explosive environments due to their superior performance against blast effects. In the design of such panels, most design methods treat blast and fragment loading independently for far-field explosions. However, the synergistic effects of combined blast and fragments loading should be accounted for in close-in explosion scenarios. In this study, a field test program was conducted to assess the damage of the steel-concrete composite panels subjected to close-in explosion of cased charges at various scaled distance between 0.39 and 0.78 m/kg1/3. Characterization test of cased charge detonation was performed to explore the combined loading effect. The analysis includes the pressure-time history from the cased charge detonation, distribution of the fragment masses and velocities over the test panels. The structural damage and response of the composite panels against the combined loading effects was measured. The results indicated that in addition to the damage from the blast wave, the panel was remarkably damaged by the fragment impact. Despite the significant structural damage, the panels maintained its structural integrity after the tests. Additionally, quasi-static load tests were conducted on the panels to quantify their load resistant differences in pristine condition and various damaged conditions due to the explosive effects.

THE USE OF UNMANNED AIRCRAFT IN THE PRODUCTION PROCESS OF DRILLING AND BLASTING AT SURFACE MINES

Surface mines that have solid rocks in their geological structure require considerable dedication to the work processes of drilling and blasting. Drilling and blasting, as one of the first work processes in surface mines - quarries, affects all subsequent work processes (loading, transport and crushing) as a result. By improving the effects of drilling and blasting, KPI results are significantly improved on all subsequent work processes, as well as on the reduced impact of mining on the environment. The paper shows the use of UAVs (unmanned aerial vehicles) for the purpose of optimizing the results of drilling and blasting in the Anhovo quarry (carbonate mineral - R. Slovenia), whose entire annual production of 1.5×106 t goes to the cement industry (Alpacem cement d.d. Slovenia). The equipment used in the aforementioned quarry is a handheld Leica GNSS RTK device, a DJI Mavic 3E drone with RTK positioning, a Sandvik Ranger DX800i drilling rig with RTK positioning, as well as BlastMetrix software for processing data obtained from drone images and projecting minefields.

Case Report and Literature Review: A Severe Case of Blast-Related Traumatic Brain Injury

AbstractBlast-related traumatic brain injuries (bTBIs), once considered the signature wound of wars, have increasingly affected civilian populations due to the rise in terrorist attacks and industrial accidents. These injuries are complex, resulting from a combination of primary blast effects, secondary projectiles, tertiary impacts, and quaternary injuries from burns and toxic gas inhalation. Understanding the clinical presentation, management strategies, and outcomes of bTBIs is essential for enhancing patient care and improving prognosis. We report a case of industrial-related severe bTBI with opened depressed skull fracture and intracranial hematoma. The patient underwent decompressive craniectomy and evacuation of clot but postoperatively had a stormy recovery and multiple complications. He eventually succumbed due to his complications. This underscores the complexity of bTBIs and highlights the importance of a multidisciplinary approach in the management of bTBIs. Further research is needed to optimize treatment protocols and rehabilitation strategies for individuals with bTBIs.

Enhancing Anti-Blast Capabilities of Pipelines with High-Performance Composite CFRP Laminate: Computational Fluid Dynamics-Based Predictive Analysis

Abstract Recent explosions highlighted the need for a thorough investigation to understand the impact of these explosions on critical infrastructural systems and networks like pipelines. This paper provides an essential understanding for developing safety protocols and interventions, strengthening resilience, enhancing public safety, mitigating socio-economic consequences, and ensuring sustained progress. Shallow buried conduits, crucial for transporting water, oil, and gas over long distances, face explosion risks due to conflicts, sabotage, terrorism, corrosion, and accidental damage. Recent blast incidents in San Francisco and Lagos underscore the devastating effects of conduit malfunctions, necessitating rigorous safety measures and technological innovations. In this research, an empty pipeline measuring 26.20 mm in thickness and subjected to a detonation initiated upon its uppermost surface is emulated, utilising the sophisticated computational capabilities of Abaqus software, integrating principles of computational fluid dynamics. Following a meticulous validation process achieved via mesh refinement analysis, the study expands to scrutinise two additional detonation scenarios — positioned above and below the pipe’s surface — while adhering to a steadfast standoff distance of 25mm. The primary objective of this scholarly endeavour is to ameliorate the deleterious repercussions inflicted upon the conduit by explosive forces, envisioning a scenario where deformation occurs without immediate rupture. To this end, a 0.15 mm thick and 200mm wide laminate composed of composite CFRP with 0°/90° fibre orientation is strategically affixed onto the upper half segment of each pipe model at the impacted region, serving as a fortification measure aimed at bolstering areas of susceptibility and potentially diminishing the magnitude of ensuing blast-induced impairment. Comparative analysis of the pipe’s performance, both with and without the applied laminate, is meticulously conducted to discern the effectiveness of this intervention. The results demonstrate a significant reduction in plastic damage with the utilisation of laminate, with models integrating CFRP experiencing an average decrease of approximately 39.94% compared to those without it. It highlights the efficacy of CFRP in protecting pipeline structural integrity against blast events.

Analysis of Reinforced Concrete Structure Subjected to Blast Load

The research focuses on a specific standoff distance of 15m & 20m , a critical parameter in blast analysis, to gain a understanding of the building's behavior under static loading conditions of blast load weight of 150kgs & 100kgs of TNT. To simulate realistic scenarios, the models are subjected to appropriate boundary conditions, including foundation constraints to account for the building's interaction with the ground. The blast load is assigned as joint loads, considering the standoff distance of the blast from the source. The standoff distance significantly influences the building's response to the blast, with profound implications for structural integrity and security. The Analysis of the Bare frame with blast load added as Joint Load, the deflection is controlled by adding Shear walls along various location along the periphery & core for 10 Story RCC Structures. The analysis is conducted using linear time history analysis (Response Spectrum Analysis) within ETABS, capturing the response of the building. Roof Displacement, Base Shear, Story Drift, Stiffness, Time period & Modal participation mass ratios are monitored during the analysis. The outcomes of this study contribute valuable insights into the structural responses of buildings to blast loads at specific standoff distances. This research advances our understanding of blast effects on buildings thereby enhancing the security and resilience of vital infrastructure in the face of evolving threats. Keywords: Blast Load, Response Spectrum Method, Roof Displacement, Base Shear, Story Drift, Stiffness, Time period & Modal participation mass ratios.

Numerical and experimental blast response of multilayer laminated glass panels

Laminated glass is used in high-security buildings to mitigate the effects of blasts and ballistic loadings. The multi-layered composition of the laminated glass (LG) panels allows the glass panes to crack and undergo large deflections while preventing glass shards from spalling by mostly remaining attached to the polymeric interlayer. To characterize multilayer LG panels under blast loading, it is essential to develop their static resistance response under uniform loading. A full-scale water chamber was used to experimentally evaluate the quasistatic response to the failure of the multilayer LG panel systems under uniform pressure. The influence of different polymeric interlayer types on the response of multilayer LG panels was studied. Also, the glass breakage patterns and deflections exhibited by various multilayer glass configurations were investigated. The response of LG panels under blast was developed using ANSYS AUTODYN, which was verified using field experiments. LG panels with an Ethylene Vinyl Acetate (EVA) polymeric interlayer experienced the most dynamic deflections, whereas LG panels with an ionoplast SentryGlas® (SG) polymeric interlayer displayed the least dynamic deflections. The results indicated that multilayer LG systems provide higher blast resistance compared to double-layer systems; the additional layers can help reduce glass breakage and maintain structural integrity. Multilayer LG system’s SG interlayer enhanced blast protection by allowing load transfer and ensuring uniform load distribution between glass layers.

Difference in rock-breaking characteristics between water-coupling blasting and air-coupling blasting

The water-coupling blasting (WCB) technology has received widespread attention due to its advantages of high efficiency and environmental protection. However, the parameters of WCB in practical engineering are generally determined based on the experience and standards of air-coupling blasting (ACB), leading to poor blasting effects and wastage of explosive energy. The study focuses on comparing the rock-breaking effects of shock waves and explosive gases between WCB and ACB to offer insights for optimizing the design of WCB. Firstly, the stress field in blasting with different coupling mediums was calculated. Then, the shock failure characteristics of rocks between WCB and ACB were analyzed. The results show that the radius of shock failure zones decreases with the increasing decoupling coefficient in WCB and ACB. On this basis, a model for calculating the shock failure range in WCB and ACB was proposed. This model can be utilized to estimate the percentage of fine-grained stone in the two types of blasting. Further, a method for distinguishing between the rock-breaking effects of shock waves and explosive gases was proposed based on the numerical simulation results of blasting damage. A comparative analysis between WCB and ACB on the rock-breaking volume by shock waves and gases was conducted. The results indicate that the failure volumes of rocks induced by shock waves and gases in WCB are 1.4–2.1 times greater than those in ACB, with a decoupling coefficient ranging from 1.26 to 1.71. Finally, a method for determining the charging structure in WCB was discussed, which has been preliminarily validated by field tests. The findings can help regulate rock-breaking effects in blasting by rationally selecting coupling mediums and charging constructions.

Numerical investigation on effects of blast loading on anti-fragment performance of hollow cylindrical UHMWPE cross-ply laminate

Ultra-high-molecular-weight polyethylene (UHMWPE) fiber composites are widely applied for bullet and explosion proofing. This study numerically investigated the dynamic response of a hollow cylindrical UHMWPE cross-ply laminate subjected to combined blast and fragment loading produced by an improvised explosive device (IED). A strain-rate-dependent, anisotropic, elastoplastic constitutive model with progressive failure was adopted for the laminates via a user subroutine and comprehensively verified against the experimental results from the literature. Three sets of simulations of fragment-only loading, blast-only loading and the combined loading were performed on different configurations of IEDs and laminates. It was found that the effects of the blast loading were much weaker than those of the fragment loading and caused very small deformation of the laminate’s middle, including somewhat pre-tension along the circumferential direction but almost no fiber fracture. Both with and without blast loading, the dense penetrations of the multiple fragments dominated the response of laminates, including perforated holes that were interconnected with each other and global ply splitting. As a result, the blast effects barely affected the anti-fragment performance of the laminates.

Optimization of relief hole blasting satisfying synergistic constraints of rock-breaking area and hole-bottom minimum burden

A strategy to optimize relief hole positions is proposed to enhance the effectiveness of tunnel blasting in rock breaking. This study employed two predefined arithmetic progressions to coordinate the distribution of rock-breaking areas and hole-bottom minimum burdens allocated to each row of holes. Iterative calculations were performed to determine the final position of each row of holes. To determine the optimal drilling scheme, modeling and simulation were conducted using a finite element method-smoothed particle hydrodynamics (FEM-SPH) coupling algorithm. This approach allowed for a comparison of the rock-breaking effects of relief holes under different constraint combinations. This study indicates that the displacement of rock particles varies in different depth zones. The largest displacements of the rock particles were observed in the middle of the charge section. For a conventional working face with a width of 12.2 m and a designed advance of 3 m, the rock-breaking efficiency is optimal when the two control ratios, rA and rW, are 1.5 and 1.4, respectively. This study advances the underground blasting design technology and contributes to energy reduction and efficiency improvements in blasting engineering.

Formation mechanisms of different kinds of blast-induced cracks and their extension characteristics in rock mass

Different kinds of cracks, including radial cracks, circumferential cracks, and spalling cracks, are formed in rock blasting. Understanding the extension characteristics of these cracks is essential for improving rock fragmentation results. However, few publications have comprehensively focused on various blast-induced cracks, and their formation mechanisms and extension characteristics are still unclear. In this study, the formation mechanisms of different kinds of blast-induced cracks are theoretically analyzed from the viewpoint of inner and outer blasting effects. Numerical models are subsequently developed to study the extension characteristics of different kinds of blast-induced cracks. Finally, based on the tunnel blasting excavation, the extension of cracks induced by cutting and surrounding blastholes is numerically simulated. The results show that rock blasting can be classified into inner and outer blasting effects. Under the inner blasting effect, radial cracks are formed in various stress states, with circumferential cracks occurring specifically in the tensile-tensile state. Under the outer blasting effect, spalling cracks form around the free surface of rock mass. In brittle rocks subjected to blast loading with higher peak values, circumferential cracks occur more frequently. In practice, it is advisable to improve rock fragmentation results by adjusting the formation of different kinds of blast-induced cracks.

Large scale massively parallel numerical simulation for blast effects on structures

An efficient large-scale parallel computing program for blast effects on structures is developed based on software platform mode, which adopts component-based three-layer software architecture to achieve disciplinary hierarchy. The parallel layer encapsulates high-performance data structures and shields large-scale parallel computing technology, enabling efficient mesh adaptivity. The common numerical algorithm layer encapsulates fluid, structural, and coupling algorithm processes providing standardized interfaces for extending numerical schemes. The physical model layer provides extension interfaces for state equations, source terms, initial boundary values, etc, to facilitate quick customization of large-scale parallel software for blast effects on structures. Typical examples verify the correctness, effectiveness and high precision of the proposed program in fluid-structure coupling problems. The parallel efficiency of 300,000 processor cores with hundreds of millions of grids reach 60.84% for the shock wave transmission. Finally, the dynamic behavior of multi-storey buildings under blast waves is simulated to reveal the damage model of the overall collapse. These results show that the software has a broad application prospect in the field of explosion. The results suggest that the software holds significant potential for application in the field of explosion, particularly in intricate and large-scale scenarios.

Flow field distribution and overpressure characteristics inside the crew compartment of a truck-mounted howitzer under the effect of muzzle blast

The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment (FFICC) of a truck-mounted howitzer during the artillery firing. This overpressure is the primary factor preventing personnel from firing artillery within the cab. To investigate the overpressure characteristics of the FFICC, a foreign trade equipment model was used as the research object, and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing condition. For comparative verification, the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment (FFOCC) and the FFICC, as well as the acceleration data of the crew compartment structure (Str-CC). The research findings demonstrate that the overpressure–time curves of the FFICC exhibit multi-peak characteristics, while the pressure wave shows no significant discontinuity. The enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC, leading to sustained high-amplitude overpressure. The frame-skin structure helps attenuate the impact of muzzle blast on the FFICC. Conversely, local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.

Experimental investigation on damage development and failure mechanism of shield tunnel lining under internal blast considering stratum-structure interaction

With the expansion of international terrorism and the potential threat of attacks against civil infrastructure, the dynamic response and failure modes of underground tunnels under explosive loads have become a prominent research topic. The high cost and inherent danger associated with explosion experiments have limited current research on tunnel internal explosions, particularly in the context of scaled model tests of shield tunnels. This study presents a series of scaled model tests under 1 g-condition simulating internal blast events within a shield tunnel based on the prototype of the Shantou Bay Tunnel, considering the influences of surrounding stratum and equivalent explosive yield. Three different TNT explosive yields are considered in the model tests, namely 0.2, 0.4, and 1.0 kg. The model tests focus on the damage behavior and collapse modes of the shield tunnel lining under internal explosive loads. The model tests reveal that the shield tunnel is prone to damage at the joints of the tunnel crown and shoulder when subjected to internal explosive loads, with the upper half of the tunnel lining experiencing segment collapse, while the lower half remains largely undamaged. As the TNT equivalent increases, the damage area at the tunnel joints expands, and the number of segment failures in the upper half of the tunnel rises, transitioning from a damaged state to a collapsed state. The influence of “stratum-structure” interaction is investigated by comparing two models, one with overburden soil and the other positioned at the ground surface. The model tests reveal that the presence of soil pressure and confinement can significantly enhance the tunnel resistance to internal blast loads. Based on the observation of the model tests, five different damage modes of segment joints under internal explosion are proposed in this study.

Optimization and application of smooth blasting parameters based on radial uncoupling coefficient

For a rational selection of smooth blasting parameters, this study proposes a calculation method for the radial uncoupling coefficient (Kd), based on the rock rupture mechanism under explosive load. The hole spacing (h) and the thickness of the smooth blasting layer (w) were also determined. A numerical analysis model was established to verify the accuracy of the calculated results, which were subsequently applied with success to the Tongchuan Tunnel project. The findings reveal that at the specific tunnel location of DK96+152, the optimal values for Kd, h, and w were calculated to be 1.7, 0.5m, and 0.6m, respectively. The numerical simulation outcomes were found to align with the theoretical calculations. By applying the optimized smooth blasting parameters at the Tongchuan Tunnel construction site, the measured maximum overbreak distance was reduced by 0.27m(64%)compared to the pre-optimization period, and the overbreak area was decreased by 2.82m2(57%). This optimized approach resulted in the achievement of an ideal smooth blasting effect, demonstrating its potential to serve as a valuable reference for the rational selection of smooth blasting parameters in actual engineering projects.

Nest-shaped hollow-encapsulated Pd catalyst enhances the catalytic performance of hydrogen peroxide directly synthesizing from hydrogen and oxygen

A well-defined structural morphology can significantly construct a special catalytic micro-reaction environment to enhance the catalytic performance of Pd catalyst in the direct synthesis of hydrogen peroxide from hydrogen and oxygen (DSHP). In this study, SiO2 was used as a rigid template, PdCl2 as the Pd precursor, and dopamine hydrochloride (DA) as the carbon and nitrogen source to synthesize a nest-shaped hollow-encapsulated Pd catalyst named PdMulti@ONHCS. This catalyst was successfully constructed via high-temperature pyrolysis of poly dimethyl diallyl ammonium chloride (PDDA), which generated a blasting effect crucial for this formation. Characterization analysis, catalytic performance evaluation experiment, and molecular dynamics simulation were conducted to explore the structure-performance relationship of PdMulti@ONHCS catalyst in DSHP. Both experimental and simulation results consistently showed that the nest-shaped hollow structure of PdMulti@ONHCS catalyst created a distinctive catalytic microreactor environment with a spatial mass transfer constraint, which was not only conducive to adsorption and enrichment of H2 and O2 at Pd active sites to produce H2O2. In addition, the generated H2O2 can be desorbed from Pd active sites in time and rapidly diffused into the reaction solution, effectively inhibiting the dissociation of species containing OO bonds on the Pd surface, resulting in severe hydrogenation and decomposition side reactions, and improving H2O2 productivity and selectivity.

Closed Trauma of the Abdomen by Blast Effect

Closed Trauma of the Abdomen by Blast Effect

Effects of structural configuration on perforation/spalling damage and secondary fragment velocity of reinforced concrete slabs subjected to close-in explosion

Reinforced concrete (RC) slabs are vulnerable to localized damage from close-in TNT explosions, suffering perforation and extensive spalling damages that generate high-velocity secondary fragments posing severe risks to nearby facilities and personnel. Current numerical methods such as the Finite Element Method (FEM) face challenges in accurately predicting fragmentation due to mesh distortion caused by large deformations and discontinuities, underscoring the need for enhanced modelling techniques. As a result, although numerous studies have numerically investigated how structural configurations influence RC slab damage under blast loads, the issue of mesh distortion and element erosion in FEM has led to the inability in reliably predicting the associated threats from high-velocity fragments. This study numerically investigates the influences of structural configuration (e.g., concrete strength, reinforcement ratio and layout, dimensions of slabs, and concrete cover depth) on the perforation/spalling area and fragment ejecting velocity of one-way RC slabs subjected to close-in explosions through an ALE-FEM-SPH numerical model, which has been demonstrated effective and reliable in the authors’ previous studies. The results indicate that concrete strength and slab thickness most significantly affect both the damage and fragment characteristics, while the slab's width-to-height ratio, reinforcement ratio, and layout, have less influence, particularly on fragment velocity. Empirical equations derived from extensive numerical data are provided to help engineers and security personnel quickly evaluate the blast effects on RC slabs. The accuracy and robustness of the proposed formulae, which can be straightforwardly used to predict blast fragments of reinforced concrete slabs, have been statistically evaluated and the proposed formulae demonstrate satisfactory precision, with less than 20 % error in estimating damage area, maximum fragment velocity, and total kinetic energy of fragments.

Damage behavior of the surrounding medium caused by different blast-induced dynamic and static loadings

The combination of the dynamic action of explosion stress wave and the static action of explosion gas expansion is what primarily drives rock-breaking blasting, and their different intensities lead to different blasting effects. Therefore, experiments were conducted to explore the damage behaviour of the surrounding medium caused by different blast-induced dynamic and static loadings using digital laser Schlieren and digital laser dynamic caustic systems. The results were as follows: In the air medium, when the explosives detonated, TATP (triacetone triperoxide) had the strongest quasi-static effect, and the highest velocity explosion shock wave and products compared with those of NHN (nickel hydrazine nitrate) and DDNP (diazodinitrophenol). Part of the TATP explosion product was ahead of the shock wave front, whereas for NHN and DDNP, their explosion products were behind the propagation of the shock wave front. The highest pressure peak of TATP was the result of the combined action of the shock wave and explosion product impacting the sensor. In the solid medium, NHN, the explosive with the strongest dynamic load, had the strongest stress wave and highest stress intensity factor peak of the main crack. The velocity reached the peak value at the early stage of propagation, and the dynamic action had a dominant effect on the cracking of the crack; the stronger the dynamic action, the higher the crack initiation energy. The stress intensity factor and propagation rate of the main crack of TATP with the strongest quasi-static effect decreased slower than those of the other explosives; therefore, the main crack propagation time and length were the longest. After cracking, the quasi-static effect dominated the process of crack propagation, where the stronger the quasi-static effect, the longer duration of the driving force of crack propagation. The research results provide a basis for customising explosives for different functions in practical engineering and realising the fine and efficient utilisation of explosion energy.

A big bang theory of big brain trauma.

One of the biggest neurophysiological science news headlines of the 2024 summer reported a critical link between post-traumatic stress disorder (PTSD), suicide, and brain injury from blast events in members of the elite US fighting force, Navy SEALS. Researchers from the Department of Defense/Uniformed Services University Brain Tissue Repository (DOD/USU BTR) had discovered a border of neural damage between the layers of white and gray matter comprising the cortical folds of service members' brains. Described as a distinctive anatomical line of astroglial scarring along the shared junctions of gray and white cellular zones of the brain, this tissue injury was unlike that observed for concussive brain trauma. Rather, it was consistent with blast biophysics of mammalian tissues. In this new study, the damage appears to be correlated with long-term, repeated exposure to blast waves from nearby explosions or firing weapons. A cascade of progressive unexplained behaviors, cognitive decline, and severe depression in the trained fighters ensued. This analysis suggested that repetitive, impulsive pressure waves traveling through the service members' heads and brains with each blast had compromised their cognitive centers, setting a downward trajectory in their mental and physical health.