bluuebunny/crossref_metadata_2025 huggingface dataset:
Boron-based combustion modifiers on combustion performance of boron-based fuel-rich propellants
Authors: He Na , Gao Xifei , Xin Yanping , Zhu Xueliang , Zhang Weihai , Zhang Yongli , Wei Jiao , Zhang Yuxuan
Published: December 2024

This paper investigates the effects of different boron-based combustion modifiers on the rheological, combustion and energy release characteristics of boron-based fuel-rich propellants. The results show that boron-based high-energy ionic salts (B1, B2, B3) and boron-based metallic fuels (Mg-Al-B), when combined with (AB+TAB)/HTPB mixed systems, exhibit superior rheological characteristics. The B2 and Mg-Al-B agglomerated particles demonstrate low apparent activation energy and high reaction rate constants, facilitating the rapid combustion of boron-based fuel-rich propellants. Furthermore, the synergistic catalytic effect of B2 and Mg-Al-B increases the static burning rate pressure index from 0.38 to 0.54 at 0.5∼5 MPa, with a dynamic pressure index of 0.52. These modifications improve the energy release efficiency η
c1 of the propellant, the energy release efficiency η
c2 of the primary combustion, and the combustion efficiency η
B of boron powder by 12.93%, 24.61%, and 34.06%, respectively. The primary injection efficiency exceeds 98%, significantly enhancing the combustion performance and energy release efficiency of boron-rich fuels.
Effect of SnO2 Nanoparticles Content on Ignition and Combustion Performance of Boron Particles
Authors: Deng Xueyuan , Yang Suyuan , Du Miao , Li Shuai , Mi Jing , Hao Lei , Wu Chenkai
Published: December 2024

Boron is a potential metallic fuel substitute for solid propellant, however, its application has been limited by the surface oxide layer. Metal oxide are proposed to improve its oxidation performance. In the paper, boron particles were coated with SnO2 nanoparticles (n-SnO2) by a hydrothermal method. The B@SnO2 particles were characterized by SEM, TEM, and XRD. The results show that the boron particles were uniformly coated with n-SnO2 with range from 5 nm to 20 nm. The thermal oxidation, ignition and combustion performances were characterized by using TG-DSC, oxygen bomb calorimeter and laser ignition testing system. The relationship between the content of SnO2 and the performance of ignition and combustion were established. Significant reduction of oxidation temperature of boron particles was observed after coating with n-SnO2. The effect was more obvious with increasing SnO2 content. Furthermore, with the increase of SnO2 content, the ignition delay time of B@SnO2 particles decrease, its heat of combustion and combustion efficiency first increase then decreases gradually. Compared with boron particles, the maximum combustion efficiency of B@SnO2 particles reaches to 86.03%, increased by 57.19%, and the minimum ignition delay time reaches to 8 ms, decreased by 46.7%. Therefore, the coating significantly reduced ignition temperature and increased heat, and the particles has profound application potential as the solid fuel.
Calculation of closed combustion performance based on evolution of gun propellant burning surface
Authors: Yuan Maobo , Liu Jihua , Zhao Yuhua , Jin Jianwei , Zhao Hongli , Guo Zhigang
Published: December 2024

In order to enhance the combustion performance evaluation ability of irregularly shaped gun propellants and accelerate the development of propellant energy-release control technology, the present work provides the calculation method of closed combustion performance based on the evolution of gun propellant burning surface. The 3-D structure of the gun propellant should be built, and then a steady-state heat conduction equation with a source term is set, which can be considered as the Poisson equation with a diffusion term. The variable in the equation is the burned web thickness of the propellant grain. Afterwards, finite element meshing was performed on the 3-D structure to obtain a dynamic database of equivalent surfaces with burned web size. The pressure during the closed combustion process can be obtained from the mass conservation equation as a function of the burned web thickness. Furthermore, the combustion time field can be derived based on the functional relationship between burning-rate and pressure. Ultimately, the variation of gas pressure versus time in the closed bomb could be obtained. The results showed that the burnout time of the tubular propellant was 1.6 ms shorter than that of the inner pore offset 0.5 mm under the design conditions. This research can provide researchers with a new method for calculating the closed combustion performance of irregular gun propellants, which can be applied to the design of propellant shapes and the study of launch safety of propellant charges.
Experimental study of propellant/liner interface fracture characteristics
Authors: Wang Guijun , Wu Yanqing , Wang Yuxiang , Huang Fenglei , Wang Tao
Published: December 2024

The propellant/liner interface debonding is one of the main failure modes affecting the structural integrity of solid rocket motors. In order to study the mechanical properties of the propellant/liner interface, the Double-Cantilever Beam (DCB) specimen of the propellant/liner interface was improved. Based on the propellant/liner interface DCB specimens, tensile tests at different temperatures and loading rates were carried out. Based on the digital image correlation(DIC) method, the strain field of the whole DCB specimen and the propellant part was analyzed respectively. Meanwhile, the fracture morphology of DCB specimen was analysed. The results show that the improved specimen can effectively characterize the properties of the propellant/liner interface. The propellant/liner interface shows obvious temperature and strain rate dependence, and the effect of temperature on the propellant/liner interface performance is more significant than that of loading rate. The deformation at the propellant/liner interface of the DCB specimen can reach about 50%, and the interface fracture mode of propellant/liner is cohesive fracture.
Numerical study of thermal safety of passive semiconductor bridges based on multiphysics field coupling
Authors: Zhang X , Liu P , Duan JN , Feng F
Published: December 2024

In order to study the thermal safety of high passivation semiconductor bridges, a NTC (negative temperature coefficient) thermistor is integrated into the SCB (Semiconductor Bridge), and the SCB-NTC shunt and the temperature change in the bridge area and the temperature change in the bridge area of the SCB are investigated based on the COMSOL under the excitation of different constant current sources. The results show that NTC has an obvious inhibiting effect on the temperature increase of SCB bridge area. The thermal equilibrium temperature of the bridge area is about 172 °C under 1.5 A excitation condition; under 2 A excitation condition, the thermal equilibrium temperature of the bridge area is about 206 °C. The current flowing through the NTC under 1.5 A excitation condition rises from 0.45 A to 0.78 A and stays unchanged; under 2 A excitation condition, the current flowing through the NTC rises from 0.6 A to 1.35 A and stays unchanged. By integrating the NTC on the SCB, the NTC thermistor shunt can reach 52%∼67.5%, which can reduce the temperature of the bridge area by 55%∼70%. The above simulation results are compared with the experimental results, and the simulation results are in high agreement with the experimental results.
Energy Release Characteristics of Laser Ignited Al/PTFE Reactive Materials
Authors: Wang Tianyi , Zhang Zhenwei , Ji Cheng , Cai Yuepei , He Yuan , He Yong
Published: December 2024

In this study, the energy release mechanism in aluminum/polytetrafluoroethylene (Al/PTFE) reactive materials was investigated through combustion experiments employing laser ignition. Al/PTFE specimens with different Al particle sizes and different ratio were prepared by molding and sintering. The combustion processes and temperature fluctuations were documented using high-speed cameras and temperature sensors. It was found that specimens with micron Al failed to sustain combustion following the cessation of laser energy, whereas specimens with nano Al displayed a lower ignition threshold and sustained self-propagating reactions. The high surface reactivity and extensive specific surface area increased the susceptibility of specimens with nano Al to oxidation, which, following initial reactions, resulted in diminished reactivity and reduced energy release compared to specimens with micron Al. As the Al content increases in the specimens, the time required to reach the highest reaction temperature is reduced, concurrently with an augmentation in energy liberated. This correlation substantiates that within specified boundaries, an elevation in Al content precipitates an enhancement in both the efficacy and magnitude of the energy release.
Analysis and comparative study on the detonation performance of different heavy metal azides through theoretical calculations
Authors: Peng Yue , Zhang Lei , Xie Mingwei , Meng Qingying
Published: December 2024

In this paper, the detonation performance of different types of heavy metal azides is analyzed and compared using the detonation thermodynamic calculation method. Using the Virial-Peng-Long (VPL) equation of state (EOS) which based on the theoretical values of the 2-5th order virial coefficients of the Exponential-6 (Exp-6) potential to describe the high temperature and high pressure thermodynamic state of the gaseous detonation product N2, and the trinomial EOS Wu-Chen-Peng (WCP) which based on the universal Debye temperature specific volume function was used to describe the thermodynamic relations of the corresponding condensed metal product. Based on the VPL EOS and WCP EOS, the detonation velocity, detonation C-J (Chapmann-Jouguet) pressure and isentropic expansion P-V relations of detonation products for four kinds of metal azides: lead azide, silver azide, cuprous azide, and cupric azide, were obtained at different densities through detonation thermodynamic calculations. The detonation performance of different metal azides was compared and evaluated by combining detonation heat and gaseous product content. The reaults show that cupric azide has relatively better detonation velocity and work capacity, especially suitable for initiation by driving flyer. Lead azide and silver azide have higher detonation C-J pressure which are suitable to direct initiation.
The detonation pressure measurement of lead azide based on PDV technology
Authors: Yuan Xiaoxia , Yang Kun , Qin Guosheng , Wang Kexuan
Published: December 2024

In order to measure the detonation pressure of lead azide, a test method and device for the detonation pressure of lead azide was designed in this paper. Based on the PDV technology, the interface particle velocity tests of lead azide were carried out, and the heights of the charge were 1.5 mm, 2.0 mm and 4.0 mm respectively. Then, the interface particle velocity curves of lead azide with different heights were obtained by mediating the original data. Owing to the interface particle velocity variation process corresponding to the pressure distribution in its ZND detonation model, we can obtain the VM peak and CJ point of lead azide from interface particle velocity curve of 4.0 mm charge height. The VM peak and CJ point of lead azide is 1553±30 m/s and 1031 m/s, respectively. Finally, based on impedance matching formula, it can be obtained that the VN pressure is 25.097 GPa and the detonation pressure (CJ pressure) is 15.705 GPa, and the duration of the detonation reaction zone is about 49 ns.
Life Assessment Method And Current Situation Analysis of Initiating Explosive Device
Authors: Li Fang , Wang Hong gang , Wang Meng , Wang Yanyan , Zhang Dong dong
Published: December 2024

This paper analyzes and studies the methods and current status of life assessment for initiating explosive devices in China. The main focus is on the analysis of methods and standards for evaluating the storage life of initiating explosive devices, the impact of acceleration models and coefficients on the results of life assessment, and the impact of experimental program design on the results of life assessment. The reasons for the deviation between the results of life assessment for initiating explosive devices using accelerated life testing methods and the storage life of initiating explosive devices in natural environments are discussed, and suggestions for the use of life assessment methods for initiating explosive devices are proposed.
Laser Response Mechanism of Typical Ammonium-Nitrate and Furazan based Energetic Graphene Oxide Composites
Authors: Chen Jianhua , Lu Feipeng , Yu Xiaogang , Zheng Wei , Peng Qiqi , He Aifeng , Jing Bo
Published: December 2024

Graphene oxide (GO) had been used for the energetic performance regulation of high energy density energetic materials (HEDMs), such as balancing the contradiction between high energy and high sensitivity of ammonium nitrate and furazan based energetic materials. However, GO based energetic composites shown photosensitization characteristics, which could bring risks to their safe application in novel battle environments. In this paper, cyclotrimethylnitrosamine (RDX), hexanitrohexazazane (CL-20), and 3,4-dinitrofurazanyl Furoxane oxide (DNTF) were taken as typical research objects to prepare their GO based energetic composites, and an evaluation method of laser response characteristics of energetic materials was established, the laser response characteristics and hot spot ignition mechanism of GO@RDX, GO@CL-20, and GO@DNTF were obtained. This work not only provided ideas for the safety design of energetic materials, but also provided support for applications such as reliable ignition output.
On experiments of the Al/PTFE cylindrical shell under inner explosive loading
Authors: Du J Y , Guo L , Zhang Z , He Y
Published: December 2024

To investigate the reactive incandescence of the Al/PTFE energetic material under explosive loading, this study utilized explosive-driven experiments with two inert control groups, Al2O3/PTFE and W/PTFE. According to explosion experiments, it is found that the firelight of the Al/PTFE cylindrical shell are brighter, cover a wider range, and last longer than the inert shell. Furthermore, it is considered that the subsequent aerobic reactions have a relatively minor impact on the shock wave parameters, especially the peak overpressure.
Prediction of fragment impact energy release overpressure based on machine learning
Authors: Zhang Z , Zhang Z Y , Du J Y , Cheng J , Chen P , Ma Y , Wang C T
Published: December 2024

The overpressure within a quasi-sealed chamber serves as a crucial metric for assessing the energy release behavior and impact potential of energetic fragments. Combining one-dimensional shock wave theory and material microparameters, different machine learning models were trained to predict the overpressure generated by different energetic fragments. The final results demonstrate that the RF model achieved the highest prediction accuracy, with an RMSE error of 0.0251 MPa. Notably, the mathematical expression generated by symbolic regression only incorporated four features. After iterative training of symbolic regression using four features, the prediction accuracy was notably higher. This accuracy surpassed that of the DT model and KNN model, which were trained with eight features. However, it still fell slightly below the accuracy of the GBDT model, which was also trained with eight features.
Effect of particle gradation on the rheological properties of three-component HTPB propellants
Authors: Zhang Xu-long , Deng Zi-tong , Xu Wen-long , Jiang Li-ping , Xu Hui-Xiang , Qu Bei , Huang Hai-tao , Li Ji-zhen
Published: December 2024

To compare the applicability of particle gradation models commonly used in solid propellants, a variety of particle gradation models including constant-ratio gradation, maximum loading fraction gradation, and rolling gradation model, were used in the study of three-component HTPB propellants. The initial conditions were set to configure the slurries of the propellants, and the viscosity of the slurries was measured by using a rotational rheometer, and the power model was utilized to determine the rheological superiority of the slurries. The reason for the better rheological properties of the slurries is explained in conjunction with fractal theory. The results show that the Rolling gradation model is the best suited for AP single particle gradation of the three-component HTPB propellants and that its higher applicability may be related to having a higher fractal dimension number, which is positively correlated with the rheological properties. These findings help to optimize the formulation design of a three-component HTPB composite solid propellant and improve its performance.
An image processing method for visualizing the Mach reflection process.
Authors: Haoyu Zhang , Yuxin Xu , Xiaolong Jiao , Xudong Li , Peng Xu
Published: December 2024

In near-ground explosions, Mach reflection occurs, generating Mach waves with considerable destructive power. Consequently, the propagation of these waves is a critical focus in the study of such detonations. This study presents a visualization method for the Mach reflection process based on image processing. By employing image processing techniques, the trajectories of the triple points are obtained, allowing for the analysis of their movement under varying explosive charges and heights. Results indicate that the interaction between detonation products and air, coupled with multiple reflections of rarefaction waves within the detonation products, leads to the convergence of these rarefaction waves at the explosion center, forming new shock waves. These shock waves, upon interacting with the ground, reflect again, resulting in multiple peaks in the overpressure time curves at measurement points. Additionally, it was observed that a smaller scaled height of the explosive charge results in a more curved Mach stem. For a constant explosive height, increasing the explosive quantity only marginally increases the height of the Mach stem. This research provides valuable insights into the Mach reflection phenomena in near-ground explosions.
Advances in surface coating and performance enhancement of ammonium perchlorate
Authors: Liu Chao , Chang Shengquan , Su Linan , Wang Hao
Published: December 2024

Ammonium perchlorate (AP), which has the advantages of high oxygen content, good thermal and chemical stability, and no solid residue after thermal decomposition, is considered to be the most widely used oxidiser for solid propellant applications. However, the high mechanical sensitivity, moisture absorption, and thermal decomposition temperature of AP seriously affect the performance of the solid propellant. In this paper, we systematically review the research progress of the improvement of desensitization, anti-hygroscopicity, and thermal decomposition performance by surface coating of AP. At the same time, the surface coating methods are focusing on electrospray technology, reduced pressure distillation, ultrasonic synthesis, liquid phase deposition, supercritical fluid, intermittent spray coating, and electrostatic self-assembly coating method. Among above, intermittent spray coating and liquid phase deposition method are the preferred surface coating method due to their uniformity of coating, ease of adhesion and good performance enhancement. It is expected that the research on surface coating and performance enhancement of AP can greatly promote the innovation and development of AP in the field of high burning rate solid propellant.
Study on jet formation characteristics of PTFE/Al composite energetic liner
Authors: Tian Longnian , Li Ming , Peng Yucheng
Published: December 2024

This study aims to elucidate the characteristics of composite energetic jet formation. Employing the finite element software, a numerical simulation was performed to investigate the process of jet formation in a composite energetic liner, which integrates PTFE/Al reactive material with an Al metal liner. A comparative analysis was conducted between the jet formation process of the composite energetic liner and that of conventional energetic liners, the simulation revealed that material stratification occurs during the jet formation process of the composite energetic liner, with the high-temperature region being concentrated in the metal at the jet’s head. The study further examined the impact of the cone angle and relative thickness of the composite energetic liner on the jet’s morphology and temperature distribution during the collapse formation process. It was determined that the cone angle predominantly influences the jet velocity and the distribution of the metal jet, with less significant variance in temperature distribution. The relative thickness of the composite liner significantly affects the material stratification and modifies the temperature distribution within the jet. The outcomes of this research contribute to the practical application of composite energetic liners and offer a foundational basis for further investigation into the damage effects of composite energetic warheads against airfield runway targets.
Laser ignition of a GAP/ADN/AzBT mixture: ignition behavior
Authors: Li H , Zhan L W , Xu S Y , Pei Q , Xu Y , Lu H L , Zhang Z , Yao E G , Hao H X , Zhao F Q
Published: December 2024

The laser ignition experiments of a GAA (GAP/ADN/AzBT(1,1’-Azobis-1,2,3-triazole)) mixture were carried out to study the ignition behaviours and combustion patterns during burning process. The ignition images show that GAA mixture entered a flameless burning regime following a relatively gloomy ignition period while GA mixture generated a visible flame after ignition. The ignition behaviour analysis suggested that adding AzBT to GA mixture could increase the condensed-phase heat release in burning process.
Study on the detection method of infrared spectroscopy SVM analysis of coalbed methane
Authors: Zheng Murong , Jiansheng Guo , Yuxi Zhang , Yong Jiang , Zhiguo Yu
Published: December 2024

Combining infrared spectroscopy with support vector machines (SVMs) is used for coal bed methane (CBM) analysis in measurement-while-drilling systems during coal exploration and development. The main component of CBM is selected to overcome the phenomenon of infrared saturation absorption. At the same time, carbon dioxide gas is also considered, allowing for the formation of infrared spectral data samples with distinct CBM characteristics. Based on these samples, a coal mine gas infrared spectrum analysis model using SVMs is established. By means of experimentation, the method of extracting features from CBM spectral data samples is studied, as well as the influence of the main parameters of the analysis model on the analysis results. Experimental results show that, under the condition of reasonable selection of the sample characteristics of CBM spectral data, the optimization of the analysis model is helpful in eliminating the infrared saturated absorption of methane gas. This approach has both theoretical and practical value for the development of subsequent CBM measuring instruments and the improvement of geological decision-making abilities during the drilling process.
Sea Surface Target Detection Technology: Current Status, Challenges, and Future Development Trends
Authors: Zhang Jiayu
Published: December 2024

As the largest geographical feature on Earth, the ocean not only harbors abundant natural resources but also serves as a crucial domain for modern military strategy. The development of sea surface target detection technology is of significant importance for maintaining maritime security, promoting the development of marine resources, and enhancing naval combat capabilities. However, compared to land target detection, sea surface target detection faces a more complex background environment and target characteristics. Sea surface targets are diverse and widely distributed, with their size, material, and motion status all posing different challenges to detection technology. This paper aims to provide an in-depth analysis of sea surface background environments, target characteristics, detection bands and methods, and target identification research status, exploring effective ways to improve the accuracy of sea surface target detection.
Long-range laser ranging echo signal processing method based on non-uniform multi-pulse superposition
Authors: Xu Guangbo
Published: December 2024

When a laser fuze detects a long-distance target, the noise drowns out the echo signal, which makes the signal-to-noise ratio of the echo signal attenuate severely, seriously limiting its detection distance. Based on theoretical analysis and experimental comparison, this paper proposes a non-uniform multi-pulse superposition method to improve the signal-to-noise ratio and enhance the fuzes’ long-range target detection capability. The superposition algorithm is simulated in a MATLAB environment, and the test results prove the method’s effectiveness.
A Robust Visual Tracking Method based on Correlation Filter
Authors: Cao Chuanshuo , Ma Zhenyu , Zhao Yangyang , Guo Chen
Published: December 2024

Although the fast discriminative scale space tracking(fDSST) method shows superior performance for short time visual tracking, it is prone to tracking failure when the target is occluded or moving fast in case of long time tracking. To address this issue, we proposed a novel enhanced visual tracking method based on fDSST for robust tracking. Specifically, based on correlation filter response map we design a visual tracking status discrimination method by integrating Peak to Sidelobe Ratio(PSR) and the number of response peaks. Then, we design an adaptive model update method coupled with extended search area strategy to reduce the probability of target loss. Extensive experiments are performed on challenging benchmark sequences from Online Object Tracking Benchmark(OTB) with significant target occlusion and fast motion. Ours results show that the proposed approach improves the DP by 11.9% and AUC by 8.4% compared to the baseline fDSST, and operates at real-time.
Research on Array Magnetometer Spectroscopy Technology Based on Diffractive Optical Elements
Authors: Yang Hui-Xin , Li Wei , Xu Jing-Yang
Published: December 2024

With the development of Spin-Exchange Relaxation Free (SERF) atomic magnetometers, human weak magnetic measurement has become a hot research direction in the medical field. Cardio-cerebromagnetic monitoring is a new medical detection method in the medical field. Array magnetometer is the core device of cardio-cerebromagnetic accurate monitoring. The volume and accuracy of the array magnetometer directly determine the wearability and sensitivity of the device, and the laser beam splitting system has a great influence on its accuracy and volume. Because the diffraction beam splitting method has the advantages of high beam splitting efficiency, good beam performance consistency, small space occupation, etc., it is suitable for the laser beam splitting module of array magnetometer, which does not reduce the accuracy while reducing the volume. In this paper, we innovatively apply the diffraction beam splitting scheme to the laser beam splitting module of the array magnetometer, with the goal of miniaturizing the integration of the beam splitting module and improving the output accuracy of the array magnetometer. The design and fabrication of a high-performance diffraction beam splitter applied to the beam splitting system of the SERF atomic magnetometer, as well as the output beam quality and power balance of multiple laser beams, ensure the detection accuracy of the array magnetometer. It is important to carry out related studies of laser beam splitter technology for magnetometer development.
Deformation strategy of deformable mirrors for a typical zooming system
Authors: Ning Yan , Chen Shuailin , Gao Dengwei , Zhou Yicheng , Liu Kui , Zhang Mengdian
Published: December 2024

This paper presents a deformation strategy of deformable mirrors (DMs) for a typical zoom system. This deformation strategy provides a design method for the surface profile of zooming. It consists of mathematical model of zoom surface profile and the designing of zooming surface profiles loaded on each DM. The simulation experiments and image aberrations analysis are discussed to verify the reliability of the deformation strategy. The experimental results show that the proposed strategy exhibiting a zoom ratio of 2.0×.
Monocular Vision-Based 3D Reconstruction Method for Parts in Opto-Mechanical Assembly
Authors: Gu Ye , Zhang QingPeng , Cao XueZhe
Published: December 2024

In automated assembly, accurately capturing multi-dimensional parameters of parts is essential. Traditional methods include teaching methods or laser-based approaches, with the former relying on experience for pre-calibration and the latter being costly. This paper proposes a low-cost, monocular vision-based method for 3D reconstruction in opto-mechanical assembly. Taking the laser crystal component, including the laser gain medium and its heat sink, in a solid-state laser as an example, a monocular camera is firstly mounted on a robot and captures images of parts from specific angles. Due to the reflective properties of metal surfaces, some image information is lost. To address this problem, a 2D gamma function-based adaptive illumination correction algorithm is then proposed. Next, the improved SIFT algorithm is used to extract and match feature points from the collected images. Subsequently, the SFM approach generates a sparse point cloud, which is then densified using the CMVS/PMVS algorithm. Finally, the Poisson surface reconstruction algorithm is used to complete the 3D reconstruction of the laser crystal heat sinks. Experimental results indicate that the adaptive correction algorithm for non-uniform illumination images can extract more feature points and improve the number of matches. The reconstructed 3D model has high accuracy, providing important technical support for the next step in achieving automated opto-mechanical assembly.
SiamMask RAM for Underwater Target Tracking in Sonar Images
Authors: Xue Xiao-Wei , Dai Qi , Zhao Ming
Published: December 2024

Target tracking based on sonar images plays a crucial role in underwater coordinated operations and strikes. In this paper, aiming to address the problem of underwater noise interference and target boundary blurring in sonar image, we propose an enhanced SiamMask network, SiamMask-RAM, for underwater target tracking. By combining hybrid attention and cross correlation structures, a new similarity metric branch is proposed to enhance perception of underwater target boundaries. Furthermore, by combining the confidence scores of the positive samples with the IoU, a ranking loss optimization strategy is proposed to reduce the possibility of mismatch between the classification and regression. Exceptionally, we constructed an underwater typical target dataset based on sonar images. The evaluation results on the sonar dataset demonstrate that SiamMask-RAM achieves a tracking accuracy of 0.752, an expected average overlap of 0.362, which are 22.6% and 21.9% better than the SiamRPN tracking algorithm, respectively. These findings indicate that the proposed method exhibits high accuracy and robustness in underwater tracking scenarios involving sonar images.
CT Scan Characterization of Thermally Tested Hollow Cylindrical Propellant
Authors: Chen Xingquan , Zhang Weihua , Wang An’yong , Xu Luping , Xiao Yang , Gao Yuling
Published: December 2024

In order to study microscopic characteristics of thermally tested hollow cylindrical propellant, BT-400 industrial CT equipment was used to scan the heights of 50mm, 150mm and 250mm from the bottom of the propellants. 1 DR image and 12 CT images obtained. The propellant’s external diameter, inner hollow diameter, CT value and density difference of each CT scan region were measured with these CT images. The results show that, compared with normal temperature (25°C) experiment, the outside diameter and inner hollow diameter of thermally tested propellant at low temperature (−45°C) decreased, and its density increased; The outside diameter and inner hollow diameter of thermally tested propellant at high temperature (+70°C) increased, and its density decreased. Although no thermal damage forms such as inclusions, cracks and debonding were found in all CT scan images of thermally tested propellants, some low-density shrinkage pores were found in some CT scan images of thermally tested propellants, but these low density pores had no effect on the density distribution and uniformity of thermally tested propellants. CT scan microscopic characterization of thermally tested hollow cylindrical propellant is of great significance to evaluate propellant quality.
Dynamic Response Analysis of Orthogonal and Skewed Slabs to Touch-off Explosion: Investigating Comparative Efficacy and Damage Mechanisms
Authors: Anas S. M. , Alam Mehtab
Published: December 2024

Skewed slabs, deviating from conventional orthogonal alignment, pose distinctive structural hurdles. Despite their aesthetic allure and spatial efficiency, their incorporation entails intricate challenges in design, analysis, and construction. Within structural frameworks, slabs are pivotal elements susceptible to devastating impacts from contact explosions, like those triggered by suitcase or parcel bombs, in numerous engineering scenarios. The events like the Beirut explosion in 2022 and the Tianjin blast in 2023 serve as poignant reminders of the urgent need to grasp and address these dangers effectively. Slabs, whether arranged orthogonally or skewed, are fundamental in various engineering frameworks. Despite their key role in load support, slabs are highly vulnerable to damage from explosions, particularly contact blasts like suitcase bombs. Understanding slab behavior under such conditions is crucial for bolstering structural resilience and devising effective defense strategies against potential threats. This research endeavors to contribute to defense technology by examining the dynamic response of both orthogonal and skewed slabs to contact explosions, furnishing indispensable insights aimed at fortifying structural security in diverse environments. The blast is emulated through the utilization of the Eulerian-Lagrangian method, employing the Finite Element Analysis (FEA) technique with the aid of the Abaqus software. Slabs featuring various degrees of skew, including 15°, 30°, and 45°, are under scrutiny, and their comparative efficacy is evaluated against the benchmark of an orthogonal slab. The performance of the orthogonal slab is validated by comparing it to data from previous experiments published in academic literature. The findings revealed that with an escalating skew angle, there’s a reduction in perforation dimensions alongside a rise in peripheral damage. Furthermore, the hierarchical order of damage severity among configurations corresponds to the angles: 15° > 30° > 45°, highlighting critical considerations for structural resilience.
Theoretical study on cushioning isolation of cushioning materials under high impact environment
Authors: Sun Xiaoting , Wang Yi , Che Jinli , Wang Wei
Published: December 2024

When a guided projectile is fired, the high pressure generated by the gunpowder gas in the chamber produces a high impact accelerationtion of tens of thousands of g in the projectile, which makes the components of the projectile withstand a huge instantaneous, high-energy, strong impact load. This type of load environment results in the deformation and failure of the internal mechanical components and damage to all type of electronic components, leading to the failure of the entire guidance system. Selecting the correct cushioning material to store or dissipate the impact energy so that the peak value of the impact is reduced to within the range of the component is an effective technical approach. In this study, a mechanical analysis of the high-impact environment inside a certain type of artillery was conducted, the axial impact load variation curve of the projectile was drawn, and a buffer isolation mathematical model of the buffer material was established. This study obtains a visualization interface using Python to solve the problem intelligently. By changing the mass of the mass block, the equivalent stiffness and equivalent damping value of the buffer material in the program script, researchers can use the model to draw the displacement, velocity and acceleration curves of the two mass blocks simultaneously, and obtain the buffering efficiency and maximum elastic compression of the buffer material. When the equivalent damping is the same, this study obtains the buffering efficiency curve and the maximum elastic compression curve changing with the stiffness through the model. The results show that in the range of elastic deformation, the buffering efficiency is proportional to the length of the buffering material but inversely proportional to its equivalent stiffness. The mathematical model provides technical support for the pre-design development and selection of cushioning materials in high-impact environments.
Study on Protective Properties of Metal Confined Ceramic Hollow Ball Composites
Authors: Wu H L , Yu G J , Wang Q C , Jiang C Y , Sun Y J , Li X
Published: December 2024

Metal confined ceramic hollow ball composite was prepared by low pressure casting impregnation molding process. Because the ceramic hollow ball is fully constrained by metal in the circumference and radial direction, and takes into account high hardness of ceramic and strength and toughness of metal, it has a strong back strength and energy absorption effect and excellent impact resistance when it is penetrated by projectiles. The protection test of metal confined ceramic hollow ball composite material was carried out by using 14.5mm ballistic gun and firing 14.5mm perforating projectile. The test results show that the average protection coefficient of metal confined ceramic hollow ball composite structure is 1.53, and the damage area of metal confined ceramic hollow ball composite is small, and it has great advantages in resistance to multiple bullets.
Theoretical and Experimental Research on Energy Distribution Models during Hypervelocity Impacts
Authors: Ming-Kai Guo , Xing Chen , Zhong-Hua Cui , Zhi-Wen Li , Gui-Long Wang
Published: December 2024

This study presents a comprehensive analysis of energy distribution during hypervelocity impacts, based on theoretical insights and experimental data obtained from hypervelocity impact tests. We have developed an energy distribution model for hypervelocity impacts on semi-infinite aluminum targets. In our model, the kinetic energy of the projectile is categorized into four components: plastic deformation energy of the target plate, spalling energy of ejected debris, energy associated with temperature increase, and electromagnetic radiation energy. Our findings indicate that the majority of the projectile’s kinetic energy is converted into spalling and plastic deformation energies during the impact, with a smaller fraction being allocated to thermal and flash radiation energies. Notably, spalling energy constitutes 65% of the total kinetic energy dissipation, while plastic deformation accounts for 25%. Additionally, we have formulated an empirical model for flash radiation efficiency that takes into account the impact velocity and target thickness. This model is found to be in close agreement with our experimental outcomes, with an error margin maintained within 10%. The model developed in this paper holds significant implications for the development of space target damage assessment methodologies under over-the-horizon conditions.
Full-scale test analysis of impact resistance of prestressed reinforced concrete containment
Authors: Meng Xin , Wang Yutao , Li Jin , Zhang Qidong
Published: December 2024

The failure mechanism of prestressed reinforced concrete structures under high-speed impact loads has always been a frontier research hotspot. In this experiment, the relationship between the impact force and time of the prestressed reinforced concrete structure under high-speed impact load was studied by rocket skid test using the real “Turbojet-6” engine, which provided data support for the subsequent analysis of the nonlinear dynamic response of the structure. The test results show that prestressing can enhance the local penetration resistance of concrete containment to a certain extent. Under the impact of the “Turbojet-6” engine, the prestressed reinforced concrete containment can keep the concrete structure intact, the steel lining unyielding, and the steel bar unbroken, which meets the structural integrity requirements.
Experimental study on ballistic resistance performance of the metal-inlaid ceramic structure
Authors: Cui X Z , Lin G Q , Li F X , Guo L , Qiao G L , Dong L S , Fan B Y , Hu D X , Bao Y L , Liu Y S
Published: December 2024

The metal-inlaid ceramic structure was fabricated by inlaying ceramic columns into the steel orifice plate by mechanical processing, and ballistic resistance performance of the metal-inlaid ceramic structure was studied by launching 105 mm armor-piercing simulated projectile from a 25 mm ballistic gun. Experimental results show that the damage area of metal-inlaid ceramic plate was a circular area with a diameter of 60 mm. There was deflection effect in the side arc surface of cylindrical ceramic cylinder after the penetration of the projectile. The protection coefficient of the metal-inlaid ceramic structure was 1.89.
Dynamic compression mechanical behaviour and ignition characteristics of aluminium-containing PBX explosives with different densities
Authors: Zhao Dong , Qu Ke-Peng , Hu Xue-Yao , Xiao Wei , Dong Ze-Lin
Published: December 2024

Due to the limitations of the processing technology, there are inevitably some differences in the explosive charge density, so that the material exhibits different mechanical behaviour and ignition characteristics, affecting the safe use of explosives. In order to study the dynamic compressive mechanical behaviour and ignition characteristics of an aluminium-containing PBX explosive with different densities, the samples with different densities were loaded quasi-statically and dynamically using electronic universal testing machine, split Hopkinson pressure bar and drop-weight loading device. The compressive stress-strain curves at different strain rates and the critical ignition height were obtained. A viscoelastic statistical cracking principal model (Visco-SCRAM) subroutine was written to analyse the internal mechanical response of aluminium-containing PBX explosives of different densities under drop hammer impact loading. The results show that the aluminium-containing PBX explosive has a pronounced strain rate sensitivity and density dependence, with the modulus of elasticity and peak stress increasing with increasing density and strain rate. Sample average density of 1.65, 1.70 and 1.74 g/cm3 the maximum stress of the explosive unresponsive and the fall height of 2500mm, more than 1000MPa; 2200mm, more than 825MPa; 2400mm, more than 907MPa, respectively. With the increase of the average density of the charge, the maximum stress and fall height of the unreacted explosives showed a tendency of decreasing and then increasing. Comprehensive analysis of test and numerical calculation results, the main influences on the ignition characteristics of low and high density samples are initial damage to the charge and mechanical properties, respectively.
Numerical Simulation and Experimental Study of a Circumferential Rod-type Damage Elements Warhead
Authors: Lin Kong , Qinqiang Kong , Guangjia Li , Cunhong Wang
Published: December 2024

In order to increase the damage power of circumferential multiple explosively formed projectile warhead, the circumferential rod-type damage elements warhead has been designed. The rod-type damage elements molding process is studied by numerical simulation. The simulation results show that the rod-type damage elements can be turned back to form by the explosive loading, the rod penetrations with aspect ratio of 4.1 can be formed, and they can penetrate 40mm thick 45# steel. To further verify the power of the circumferential rod-type damage elements warhead, the power experiment has been conducted, the results show that under the explosive loading, the rod-type damage elements are well formed and stable in flight, which can penetrate the 45# steel with the thickness of 40mm at 12meter distance.
Protective performance of helmets based on the shock wave from rocket launcher
Authors: Wu Yang , Qin Bin , Zhang Xianfeng , Lu Haitao , Xiong Manman , An Shuo , Liu Shuang
Published: December 2024

Traumatic brain injury(TBI) is one of the most common cause of major casualties in the battlefield. Soldiers may be endangering their brains when they operate certain shoulder-fired weapons or large-caliber artillery for long periods of time. It is necessary to pay attention to protection and prevention of brain injury in daily training. In this paper, the characteristic of shock wave propagation on the head with/without helmet protection when soldiers operated shoulder-fired rocket-propelled grenade launcher. The head-helmet surrogate was constructed in combination with pressure sensors. The pressure sensors were installed on the forehead, temples, top, and back of the head surrogate respectively and the sensors kept a plane with the surface of the head surrogate. The pressure variation of the shock wave flow field under different working conditions was analyzed in three types such as with/without combat helmet and integrated helmet. The results show that the peak overpressure of the shock wave from the back of the head can reach 80∼105kPa without combat helmet. The combat helmet can effectively reduce the shock wave overpressure. The integrated helmet has the best protection and can reduce the overpressure on the forehead, temple, top, and back of the head by 73%, 58%, 80%, and 83% respectively. Meanwhile the shock wave is prone to reflection and diffraction as it transmits inside the helmet. This significantly increase the overpressure of the shock wave on the forehead and the duration of the shock wave in the helmet, which has a negative effect on the protection provided by the shock wave.
Analysis and Research on the crack of a type of pressed PBX column
Authors: Yang Xiong , Lü Xi , Jia Xian-zhen , Sun Feng , Guo Xiaowei , Hao Gang , Li Shuaixiao , Huang Yafeng
Published: December 2024

In this paper, aiming at the crack found in a type of press loaded PBX column during ammunition charging, in order to reveal the cause of the crack, the industrial CT nondestructive testing technology was used to scan and analyze the column. The results shown that there was a bulge on the column surface in the crack area, and the internal structure of the bulge was a clearance surface parallel to the outer surface of the column; The finite element method was used to simulate the stress distribution in the pressing process of explosives and the stress after the column collides with the rigid plane. The simulation results of the pressing process shown that the stress concentration area and the area with the first plastic deformation were not at the crack position, but at the corner of the central hole; The rigid plane simulation results of column collision shown that the stress wave propagates in the axial and radial direction, which was consistent with the crack morphology and crack propagation direction on the surface of explosive column, and also matches the internal morphology of column crack. Through comprehensive analysis and judgment, the crack of the pressed PBX column was more likely to be caused by external force collision, and the probability of being caused by internal stress was very small.