Type Of Impactor Research Articles

Impactor identification with spallogenic Cr isotopes: The Wabar impact craters (Saudi Arabia)

AbstractPrecise measurements of Cr isotopic composition of terrestrial impactites have successfully provided evidence for the presence of extraterrestrial material and have, in some cases, allowed the identification of the type of impactor responsible for the formation of the impact structure. The high Cr abundance in most meteorite groups aids in detecting extraterrestrial contamination while their distinct isotopic compositions can help with the identification of the nature of the projectile. However, this common approach of detection and identification of extraterrestrial contamination using mass‐independent 53Cr and 54Cr variations fails when the impactor type is an iron meteorite because of their low Cr abundances (which are in a similar range to terrestrial rocks). The present study demonstrates the viability of a spallogenic Cr contribution in iron meteorites (resulting from their long cosmic ray exposure times), which compensates for their low Cr abundances and facilitates the identification of iron‐meteoritic contamination in terrestrial impactites. Thus, it broadens the scope of impactors (and impactites) that can be investigated using mass‐independent Cr isotopes from solely chondrites and primitive achondrites to include iron meteorites. The Wabar impact craters are an optimal candidate for this study, characterized by low weathering, diverse impactites, partial meteorite survival, substantial impactor material contamination, and a felsic target lithology with low background Cr concentration. The Cr isotopic composition of the Wabar background sand, which represents the target lithology, is indistinguishable from the terrestrial Cr isotopic composition range, whereas the Wabar iron meteorites show coupled spallogenic excesses in ε53Cr and ε54Cr. The Cr isotopic compositions of Wabar impactites show resolved deviations from the terrestrial Cr isotopic composition, thereby indicating the presence of Wabar meteoritic contamination. Moreover, the study demonstrates that even an impactor with a non‐carbonaceous chondritic origin, such as a IIIAB iron meteorite, can have a carbonaceous chondrite‐like signature in ε54Cr anomalies due to spallogenic Cr contamination. The study advocates for a comprehensive investigation combining platinum group elements and Cr (and/or Ni, Ru) isotopes to accurately characterize impactor types.

Development of a discreet-continuous mathematical model of a percussion device with parameters of influence on the characteristics of an impact pulse

A study of a model of a discrete-continuous type of impactor in the energy transfer phase during the impact of a striker and a tool is presented. The device is used to destroy rocks, in construction equipment, and in the oil industry. In the mathematical model, the tool is represented by a rod with a variable profile, and the striker is a discrete element with a consolidated mass. The presence of rigid and dissipative connections models the impact interaction. The motion of the interacting elements of the impactor is described by a system of differential equations linked by boundary and initial conditions. The model allows determining the parameters of influence on the characteristic of the shock pulse at variable resistance of the working medium. The force of impact of a discrete element and the contact end of the rod is represented as a power law dependent on the difference in displacements of the contacting elements. The finite difference method is used to solve the initial boundary value problem. The parameters of the difference scheme were determined through modelling problems and were as follows: time step (1, ..., 5)·10-5 s; length step – (0.1...0.3) of the tool length, and for the mixed scheme – within 0.5...0.8. It was found that the time of striker-to-tool co-impact, depending on the stiffness coefficient, was 200...300 μs. With a load of up to 90 kN in the time range of 0...4 ms, the normal stresses in the tool sections at different times were 200...250 MPa. The combination of discrete and continuous elements simplifies the calculation scheme. It allows to determine the distribution of force characteristics in the cross-sections of the tool, the force and time of impact, and the influence of the working environment on these parameters. The developed model can be used to design impactors and optimize their parameters

Numerical and theoretical analysis of multiple simultaneous impact on a functionally graded porous aluminum plate

Purpose The purpose of this study is to extract the response of the simultaneous low-velocity impact of multiple impactors on a porous functionally graded (FG) aluminum plate. Design/methodology/approach To design a porous FG structure, a series of functions are applied using the porosity coefficient, and mechanical properties including Young’s modulus, shear modulus and the density of the porous structure are presented as a function of the axis placed in the direction of the plate thickness. The first-order shear deformation theory of the plate is used. To simulate the contact process between each impactor and the plate, a nonlinear Hertz contact force is considered for that impactor independently. Findings ABAQUS finite element software is used for the verification process of the theorical equations. The effects of porous function type, radius and initial velocity of impactor are investigated for the simultaneous impact of five impactors on porous FG aluminum plate with a simply supported boundary condition. Histories of contact force and displacement of the impactor placed in the center of the beam are analyzed in detail with the changes of the mentioned parameters. Originality/value Due to the advantages of porous aluminum plate such as high energy absorption and low weight, such structures may be subjected to the simultaneous impact of multiple impactors, which is studied in this research.

The chondritic impactor origin of the Ni-rich component in Australasian tektites and microtektites

In the Earth’s crust, Ni is generally concentrated in mafic and ultramafic rocks and is coupled with Mg in Mg-olivine, Mg-pyroxene and spinel. Whether the Ni-rich, and in general, the mafic component of Australasian tektites and microtektites is terrestrial or meteoritic is still debated. To test the origin of the Ni-rich component, we studied the Ni versus Mg distribution in a large geochemical database of Australasian tektites (n = 208) and microtektites (n = 238) from the literature. Nickel contents of up to 428 µg/g in tektites and 678 µg/g in microtektites covary with Mg in tektites and in most (∼85%) of the microtektites defining a mixing trend between crustal and chondritic values, thereby documenting the chondritic origin of the Ni-rich component in Australasian tektites/microtektites. Mixing calculations indicate up to 4% and up to 6% by weight chondritic component in tektites and microtektites, respectively. A possible mafic component of terrestrial origin is observed in a minority of tektite and microtektite specimens. This finding is consistent with previous works suggesting a possible occurrence of a chondritic signature in high-Ni tektites, based on the study of highly siderophile elements and Os isotopes, and high-Ni microtektites, based on Ni, Co, and Cr ratios. The combined geochemical and isotopic analyses of high-Ni tektites and microtektites in collections worldwide may thus reveal the chondritic impactor type that generated one of the presumably largest impacts in the Cenozoic.

Dynamic crushing behaviors and failure of cylindrical lithium-ion batteries subjected to impact loading

The mechanical property and failure prediction play a significant role in engineering applications of lithium-ion batteries (LIBs), but with great difficulties due to their complicated internal structures. This paper mainly focused on dynamic crushing behaviors and internal failure mechanisms of cylindrical LIBs subjected to different impact loadings for the safety assessment and protection design. A series of dynamic experiments were conducted on typical 18650 LIBs using the drop weight impact test system. The force-electric-thermal responses and impact failure modes of the cells with state of charge (SOC) dependence were experimentally explored under different impactor types. The finite element (FE) model was also established to reveal the failure mechanisms of the battery under high-velocity impact, and its accuracy was validated by the comparison between the experimental and corresponding FE results. Furthermore, the dynamic failure mechanisms of cylindrical cells using the stress wave theory were also explored in this work. It was shown that except from impact velocities, there were significant effects of the SOCs and impactor types on dynamic responses and internal failure modes of LIBs. The failure displacement of the cell will decrease with the increase of impact velocity, but it was insensitive under low-velocity crushing. Based on the FE results, the relationships between failure displacement and impact velocity and impactor diameter were established under flat-end cylinder head impacting. This work can provide some references for multi-functional dynamic integrity design and safety assessment of LIBs.

Evaluating energy absorption of sustainable rubber crumb/kenaf composites through artificial neural network strategies for low‐velocity impact loads

AbstractThis study presents an innovative approach utilizing Artificial Neural Network (ANN) strategies to evaluate the energy absorption capabilities of eco‐friendly rubber crumb/kenaf composites subjected to low‐velocity impact loads. The primary objectives of this research were to assess the energy absorption characteristics of these sustainable composites, understand their mechanical behavior under the impact, and provide valuable insights into their potential applications. To achieve these objectives, an experimental methodology was employed. Rubber crumb/kenaf composites with varying compositions were prepared, and low‐velocity impact tests were conducted using a drop‐weight impact testing apparatus to assess their energy absorption behavior and these parameters were used as inputs for training the ANN models. The weight percentage of waste tire rubber particle (WTRP), type of impactor and impact energies are considered as input data, whereas the absorbed energy is treated as the output. Through the advanced ANN strategies, accurate predictions of energy absorption performance were achieved for the rubber crumb/kenaf composites. The Levenberg–Marquardt optimisation algorithm with ten neurons and a tangent sigmoid activation function is used to train the ANN model. The trained ANN model is tested on an unseen dataset, different from the training data. It is shown to accurately predict the energy absorption characteristics of WTRP/KRE composites with a maximum error of 4.54%. The results revealed that the composite's energy absorption capabilities were influenced by the ratio of rubber crumb to kenaf, as well as the impact velocity. Additionally, the ANN models demonstrated excellent predictive capabilities, enabling efficient estimation of energy absorption behavior. The significance of these results lies in the potential applications of eco‐friendly rubber crumb/kenaf composites. By understanding their energy absorption characteristics, these composites can be effectively utilized in various industries. For instance, they could be employed in automotive parts manufacturing to enhance occupant safety during low‐velocity impact events. Furthermore, these composites can find applications in sports equipment, protective gear, and other impact‐prone products, contributing to sustainable and environmentally friendly materials. It is believed that by adopting the proposed ANN methodology, the experimentation costs and time can be significantly reduced without compromising the accuracy of the results. The obtained results provide valuable insights into the mechanical behavior of these sustainable composites and open avenues for their implementation in diverse industries where impact resistance is crucialHighlights Development of sustainable Rubber crumb/kenaf composites Application of advanced ANN based predictive assessment of the impact response Parametric study of impactor shape and height of impact is performed The damage mechanism contributing to energy absorption is micrographically studied

Native Nickel–Iron Metals from Lonar Crater Impactites (India) and Regolith of the Moon

The Lonar crater (India) is the best preserved and most studied on Earth, formed in basalts, which makes it possible to conduct a comparative study with impact transformations of mineral matter on the Moon and other planets of the Solar System. Comparative studies have shown that impactor material, both on the Earth and on the Moon, is present in impactites not only in a geochemically dispersed form, as previously thought, but also in the form of individual submicron particles distributed in the molten target material. These are particles of native nickel, taenite, and high-nickel kamacite, which, apparently, are the transformed material of the impactor. High-nickel submicron metal inclusions are widespread in the impactites of the Lonar crater, as they were found in all studied preparations made from materials collected from different points along the rim of the crater. The high-nickel particles found in this study are an additional argument in favor of the previously stated assumption about the chondrite type of impactor.

Failure mechanism and impact resistance of all GFRP Miura-ori with platforms sandwich structure under low-velocity impact experiments

The traditional Miura-ori was optimized to Miura-ori with platforms by geometric parameters. Two types of impactors were used to conduct low-velocity impact experiments at two specific sites. The damage morphology, response characteristics, and failure mechanism under various energy were systematically investigated. The results reveal that the impact resistance of the node is better than that of the base due to crushing absorbing energy. The impact resistance of the Miura-ori with platforms sandwich structures to the flat-ended impactor is better than that of the hemispherical impactor at the node. Still, the performance at the base is the opposite.

Chromium isotopes identify the extraterrestrial component in impactites from Dhala impact structure, India

AbstractThe Dhala structure in north‐central India is a confirmed complex impact structure of Paleoproterozoic age. The presence of an extraterrestrial component in impactites from the Dhala structure was recognized by geochemical analyses of highly siderophile elements and Os isotopic compositions; however, the impactor type has remained unidentified. This study uses Cr isotope systematics to identify the type of projectile involved in the formation of the Dhala structure. Unlike the composition of siderophile elements (e.g., Ni, Cr, Co, and platinum group elements) and their inter‐element ratios that may get compromised due to the extreme energy generated during an impact, Cr isotopes retain the distinct composition of the impactor. The distinct ε54Cr value of −0.31 ± 0.09 for a Dhala impact melt breccia sample (D6‐57) indicates inheritance from an impactor originating within the non‐carbonaceous reservoir, that is, the inner Solar System. Based on the Ni/Cr ratio, Os abundance, and Cr isotopic composition of the samples, the impactor is constrained to be of ureilite type. Binary mixing calculations also indicate contamination of the target rock by 0.1–0.3 wt% of material from a ureilite‐like impactor. Together with the previously identified impactors that formed El'gygytgyn, Zhamanshin, and Lonar impact structures, the Cr isotopic compositions of the Dhala impactites argue for a much more diverse source of the objects that collided with the Earth over its geological history than has been supposed previously.

Characterization of size-fractionated carbonaceous particles in the small to nano-size range in Batam city, Indonesia

A cascade impactor type sampler equipped with an inertial filter was used to collect size-segregated particles down to ultrafine particles (UFPs or PM0.1) on Batam Island in Sumatra, Indonesia, bordered by Singapore and Malaysia during a wet and the COVID-19 pandemic season in 2021. Carbonaceous species, including organic carbon (OC) and elemental carbon (EC), were analyzed by a thermal/optical carbon analyzer to determine the carbon species and their indices. The average UFP was 3.1 ± 0.9 μg/m3, which was 2–4 times lower than in other cities in Sumatra during the same season in the normal condition. The PMs mass concentration was largely affected by local emissions but long-range transportation of particles from Singapore and Malaysia was also not negligible. The air mass arrived at the sampling site passed the ocean, which introduced out clean air with a low level of PMs. The backward trajectory of the air mass and the largest fraction of OC2 and OC3 in all sizes was identified as being transported from the 2 above countries. OC is the dominant fraction in TC and the ratio of carbonaceous components indicated that origin of all particle sizes was predominantly vehicle emissions. UFPs were dominantly emitted from vehicles exhaust emission, while coarser particles (>10 μm) were influenced by the non-exhaust emissions, such as tire wear. Other particles (0.5–1.0; 1.0–2.5; and 2.5–10 μm) were slightly affected by biomass burning. The effective carbon ratio (ECR) and inhalation dose (ID) related EC indicated that finer particles or UFPs and PM0.5-1 contributed more to human health and global warming.

Dynamic Crushing Behaviors of Cylindrical Lithium-Ion Battery Under Multiple Impacts: An Experimental Study

Abstract To understand the dynamic failure mechanisms of cylindrical lithium-ion battery (LIB) under different impact loadings, the crushing behaviors of 18650 LIBs were experimentally investigated in this work. The drop weight impact tests with different impactor heads were conducted to analyze the crushing responses of the LIBs. By changing the state of charge (SOC) of the battery, impactor types, and impact energy, the force-electric responses of a LIB under multiple impacts were explored. Macro- and micro-deformation of the batteries were further studied including SOC dependency and the failure modes of the separator. Results show that except for impact energy, the mechanical responses and failure behaviors of the LIBs under repeated impacts also depended upon the SOC and impactor types. The relationship between impact velocity and the minimum impact times was established when a hard internal short circuit (ISC) appeared to evaluate the dynamic safety of the LIBs. These results can provide guidance for the crashworthiness design and safety assessment of the batteries under multiple impacts.

Bridging the Effect of the Impactor Head Shape to the Induced Damage during Impact at Low Velocity for Composite Laminates

The present paper presents an investigation and analysis study of the effect of the head shapes of the impactor on the damages observed during low-velocity impact on T700/Epoxy composite laminate. Two types of impactors were investigated: hemispherical and flat-face. A new criterion based on the LARC05 damage model was linked as a LARC_VUMAT subroutine to simulate the impact and explore the effects of the head form shape through a three-dimensional finite element model. To properly analyze the problem, the history time of the mechanical responses, such as impact forces, bending, principal, and residual stresses, are highlighted and assessed. Additionally, a comparison with the experimental data found in the literature was performed to check the validity and accuracy of the considered finite element model. The damage occurring in the T700/Epoxy plates is illustrated for each impactor head shape. The mechanical response curves and all kinds of damage of the presented simulations are in perfect agreement with the experiments. The proposed VUMAT is efficient in the prediction of fiber kinking, matrix cracking, fiber splitting, and fiber tension of a laminate, and more importantly, it is easy to implement for other types of materials and the reproducibility of the analysis is assured.

Effects of impactors’ shape on three-dimensional woven fabric composites at low-velocity impacts

This study investigated the fabric resistance of three-dimensional (3D) woven fibreglass composites generated by impactors of three shapes, i.e., hemispherical, conical, and ogival, on four types of composite structures. Composites were fabricated using the hand lay-up technique. Crimp and mechanical impact resistance tests were carried out in accordance with ASTM D2444 standards and ASTM D3883-04, respectively. The four-floating interlocked (4FLL) yielded the strongest fabric damage tolerance for all the three types of impactors’ shapes with 6.3 kN for the hemispherical shape, 4 kN for the conically shaped, and 3.8 kN for the ogival shape. Additionally, the 4FLL generated a fabric crimp of 3.5% and 2.8% on both fabric directions. The post-impact damage showed that the ogival shape impactor penetrated samples of woven composites better than the conical and hemispherical shapes.

Impact failure characteristics of LNG carrier cargo containment system

The most critical issue related to the maritime transportation of liquefied natural gas (LNG) is the structural safety of the cargo containment system (CCS), because LNG is stored at temperatures below –163 °C. During the unloading of LNG, several types of structural components can fall into CCSs from significant heights. Thus, the structural safety of LNG CCSs against dropped objects should be verified; however, the actual failure characteristics of the primary barrier are not well understood. In this study, the failure mechanism of the primary barrier of an LNG CCS was investigated by conducting falling-object-induced structural failure tests. To clarify the effect of the failure response of the primary barrier, impact tests were performed using various membrane types and impactor types. In addition, to ensure the wide applicability of the results, a finite element analysis-based design-aid numerical method was developed by comparison with experimental observations. Excellent numerical verification results were obtained using the Johnson–Cook material model, which can be applied to the dynamic failure problem for the corrugated plates used in LNG CCSs. Finally, guidelines that could set safety standards for the primary barrier were identified, considering the shape, weight, and height of potential falling objects.

A chemical reaction insight of shock initiation criterion

Shock initiation criteria are essential to the shock initiation process and applications in modern pyrotechnics. The most commonly used shock initiation criteria are Walker and James criterion, which can very well describe the threshold data of the impactor with sufficient size. However, the criteria were also found not to provide a good fit to the data of thin, curve, or small flyers. By comparing the wave structure of the shock process with the stable detonation wave structure, a shock initiation criterion is developed based on the concept of the chemical reactions during the impact, focusing more on the properties of the explosives. Furthermore, a desktop micro-flyer initiating system was designed for the initiation of the thin metal flyer. The obtained data and classical historical data were analyzed with the proposed criterion, producing an excellent fit, with R2 values greater than 0.96. Compared to the existing criteria, the proposed criterion can weaken the influence of the interfacial properties of the impact and collapse the threshold velocity data with different impactor types to a single curve. The shock sensitivities of various explosives are also discussed based on the criterion. A denser impactor or the incorporation of impurities may contribute to the generation of the hot spot during the impact, leading to an increase in the sensitivity. The proposed criterion provides insight into the development of the shock initiation criteria and may help to understand the mechanism of shock initiations.

Geochemistry of lunar meteorite Northwest Africa 11962 and its potential source region/crater in the Procellarum KREEP terrane

AbstractLunar meteorite Northwest Africa (NWA) 11962 is a regolith breccia with a diverse range of mineral and lithic clasts. For the present study, major and trace element contents and selected isotopic compositions were determined on a homogenized bulk powder of NWA 11962 by instrumental neutron activation analysis, thermal ionization mass spectrometry, and inductively coupled plasma mass spectrometry. The chemical composition of the sample points toward an origin of the meteorite from within the Procellarum KREEP terrane (PKT). Samarium‐Nd and Rb‐Sr isotopic compositions and concentrations show a similarity to those of Apollo 15 soils and KREEP basalt. Highly siderophile element (HSE) abundances and ratios, as well as the Re/Os isotopic system, are often used as tracers of different impactor types. The 187Os/188Os and 187Re/188Os isotopic ratios are within the range of ordinary chondrites, yet some of the siderophile element and highly siderophile element ratios are comparable to those of iron meteorites. Using Fe, Th, and Ti abundances of lunar surface regolith, measured by the Lunar Prospector gamma‐ray spectrometer, we attempt to constrain potential lunar source regions for NWA 11962. By matching these possible source regions with coordinates of recently (<1 Ma) formed lunar impact craters (so‐called lunar cold spots), we localized a potential source crater of NWA 11962 at the western rim of the PKT close to Sinus Medii.

Development of Sustainable Jute/Epoxy Composite and Assessing the Effect of Rubber Crumb on Low Velocity Impact Response

ABSTRACT In the current study, the experimental assessment of influence of rubber crumb on the low velocity impact (LVI) behavior of jute epoxy composites are carried out using two types of impactors namely hemispherical and conical. Hand layup technique is used to fabricate the proposed composites. The rubber crumb is incorporated in the epoxy resin with 1.5 wt%, 3 wt%, and 5 wt%. Results revealed that incorporation of 3 wt% of rubber crumb resulted in better LVI response compared to its counterparts. Fractography studies revealed that inclusion of rubber crumb particles enhances the adhesion between resin and fiber, thereby increasing the energy absorption. In addition, they aid in reducing damage area and increasing penetration threshold of proposed composites. The current study’s systematic technique serves as a model for the efficient use and conversion of waste rubber crumb into usable natural fiber reinforced polymer matrix composites for LVI applications.

Анализ особенностей возникновения инерциального взрыва в задачах высокоскоростных ударов металлических пенетраторов в исследуемое небесное тело и метеорно-техногенных частиц в элементы космических аппаратов

The article discusses the features of the occurrence of an inertial explosion (IE) in the problems of high-speed impacts on a solid barrier of two types of impactors: metal penetrators into the studied celestial body for space contact scientific research and meteor-technogenic particles into the elements of spacecraft. The features of IE, the conditions of its occurrence and the results of theoretical and experimental studies are analyzed. The ratio of the calculated impact velocity, leading to the appearance of willows, to the speed of sound in different metals tending to a certain average value is discussed. The influence of contact and thermoelectric phenomena and the temperature of the impactor on the occurrence of IE, as well as its dependence on the cross-sectional area of the impactor, is discussed. The ways of preventing the occurrence of IE are considered.

Design of a New Type of Torsional Impactor and Analysis of Its Impact Performance

In view of the stick-slip phenomenon in deep and hard rock drilling, a new type of torsional impactor that can provide torsional impact vibration was designed. According to the working principle and structural characteristics of the designed torsional impactor, this paper theoretically analyzes the influences of different structural parameters and motion parameters on the impact frequency, impact force, and impact torque of the torsional impactor. The results show that the impact frequency f is directly proportional to the rotational speed VZ of the transmission shaft and the installed number n of torsional impact generating devices. Additionally, the impact force F is directly proportional to sine value of the impact angle α (i.e., sinα), impact hammer mass m, impact hammer rotation speed VZ (i.e., transmission shaft rotation speed), and impact hammer rotation radius r and is inversely proportional to action time Δt of the impact hammer and impact anvil. Furthermore, the impact torque M is directly proportional to the impact force F and rotary radius r of the impact hammer. This article lays a foundation for further theoretical and experimental research of torsional impactors and provides a reference for the design and testing of torsional impactors.

Fiber optic sensor embedded smart helmet for real-time impact sensing and analysis through machine learning

BackgroundMild traumatic brain injury (mTBI) strongly associates with chronic neurodegenerative impairments such as post-traumatic stress disorder (PTSD) and mild cognitive impairment. Early detection of concussive events would significantly enhance the understanding of head injuries and provide better guidance for urgent diagnoses and the best clinical practices for achieving full recovery. New methodA smart helmet was developed with a single embedded fiber Bragg grating (FBG) sensor for real-time sensing of blunt-force impact events to helmets. The transient signals provide both magnitude and directional information about the impact event, and the data can be used for training machine learning (ML) models. ResultsThe FBG-embedded smart helmet prototype successfully achieved real-time sensing of concussive events. Transient data “fingerprints” consisting of both magnitude and direction of impact, were found to correlate with types of blunt-force impactors. Trained ML models were able to accurately predict (R2 ∼ 0.90) the magnitudes and directions of blunt-force impact events from data not used for model training. Comparison with existing methodsThe combination of the smart helmet data with analyses using ML models provides accurate predictions of the types of impactors that caused the events, as well as the magnitudes and the directions of the impact forces, which are unavailable using existing devices. ConclusionThis work resulted in an ML-assisted, FBG-embedded smart helmet for real-time identification of concussive events using a highly accurate multi-metric strategy. The use of ML-FBG smart helmet systems can serve as an early-stage intervention strategy during and immediately following a concussive event.