Cylindrical specimens are commonly used in Split Hopkinson pressure bar (SHPB) tests to study the uniaxial dynamic properties of concrete-like materials. In recent years, true tri-axial SHPB equipment has also been developed or is under development to investigate the material dynamic properties under tri-axial impact loads. For such tests, cubic specimens are needed. It is well understood that static

The roll angular rate is much crucial for the guidance and control of the projectile. Yet the high-speed rotation of the projectile brings severe challenges to the direct measurement of the roll angular rate. Nevertheless, the radial magnetometer signal is modulated by the high-speed rotation, thus the roll angular rate can be achieved by extracting the instantaneous frequency of the radial magnetometer

In this study, we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), showing the presence of iron and multiple iron-based compounds oxides with

Ballistic impact response of resistance-spot-welded (RSW) double-layered (2×1.6 mm) plates (170 mm×150 mm) for Q&P980 steel impacted by a round-nosed steel bullet (12 mm diameter and 30 mm length) was investigated by using gas gun and high-speed camera system. The RSW specimens were spot welded using a 6 mm diameter electrode face producing a 7.2 mm diameter fusion zone of the spot weld. The ballistic

An adaptive wheel-legged shape reconfigurable mobile robot, based on a scissor-like mechanism, is proposed for an obstacle detecting and surmounting robot, moving on complex terrain. The robot can dynamically adjust its own shape, according to the environment, realizing a transformation of wheel shape into leg shape and vice versa. Each wheel-legged mechanism has one degree of freedom, which means

In this paper, a novel method of ultra-lightweight convolution neural network (CNN) design based on neural architecture search (NAS) and knowledge distillation (KD) is proposed. It can realize the automatic construction of the space target inverse synthetic aperture radar (ISAR) image recognition model with ultra-lightweight and high accuracy. This method introduces the NAS method into the radar image

High velocity ballistic impact deformation behaviour of Titanium/GFRP Fiber Metal Laminates (FML) has been explored. Both single and multiple projectiles impact conditions were considered. Ti/GFRP FML targets were fabricated with addition of 5% and 10% weight percentage of boron carbide (B4C) particles. Mechanical properties of Ti/GFRP FML targets were determined as per ASTM standards. High velocity

Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space were investigated through experiments and simulations. The volume of the enclosed concrete space is about 15 m3. The reactive liner enhanced shaped charge utilizes reactive copper double-layered liner, which is composed of an inner copper liner and an outer reactive liner, while the reactive material

Recent advances in on-board radar and missile capabilities, combined with individual payload limitations, have led to increased interest in the use of unmanned combat aerial vehicles (UCAVs) for cooperative occupation during beyond-visual-range (BVR) air combat. However, prior research on occupational decision-making in BVR air combat has mostly been limited to one-on-one scenarios. As such, this study

The tether deployment of a tethered satellite system involves the consideration of complex dynamic properties of the tether, such as large deformation, slack, and even rebound, and therefore, the dynamic modelling of the tether is necessary for performing a dynamic analysis of the system. For a variable-length tether element, the absolute nodal coordinate formulation (ANCF) in the framework of the

In this paper, we propose a compressive sampling and reconstruction system based on the shift-invariant space associated with the fractional Gabor transform. With this system, we aim to achieve the sub-Nyquist sampling and accurate reconstruction for chirp-like signals containing time-varying characteristics. Under the proposed scheme, we introduce the fractional Gabor transform to make a stable expansion

Cocrystallization integrates the merits of high energy and insensitivity between energetic molecules to obtain energetics with satisfying performance. However, how to obtain supramolecular synthons accurately and rapidly for predicting the structure and property of cocrystal remains a challenging problem. In this research, an efficient systematic search approach to predict CL-20/2,4-DNI cocrystal has

With the increasing number of vehicles, manual security inspections are becoming more laborious at road checkpoints. To address it, a specialized Road Checkpoints Robot (RCRo) system is proposed, incorporated with enhanced You Only Look Once (YOLO) and a 6-degree-of-freedom (DOF) manipulator, for autonomous identity verification and vehicle inspection. The modified YOLO is characterized by large objects’

MXene, a new type of two-dimensional materials, have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years. Herein, we report the intriguing light-to-heat conversion property of vanadium carbide (V2C) MXene under irradiation of millisecond laser pulse. Unlike the typical photothermal materials

The woven glass fiber reinforced composites (GFRP) subjected to high-speed impact is investigated to identify the hygrothermal aging effect on the impact resistance. Both the hygrothermal aged and unaged glass/epoxy laminates are subjected to different impact velocities, which is confirmed as a sensitive factor for the failure modes and mechanisms. The results show the hygrothermal aging effect decreases

This paper presents a combination of experimental and numerical investigations on the dynamic response of scaling cabin structures under internal blast loading. The purpose of this study is to modify the similar relationship between the scaled-down model and the prototype of the cabin structures under internal blast loading. According to the Hopkinson's scaling law, three sets of cabin structure models

3-nitro-1,2,4-triazol-5-one (NTO) is the main component of insensitive munitions (IM) formulation because of its outstanding insensitive properties. In this paper, a series of NTO/HMX-based composite explosives were prepared and characterized. The study focuses on the effect of NTO on the performance of the formulations, especially the safety performance. The results revealed that the mechanical sensitivity

Tire and rubber track interchangeable chassis combines the advantages of tire and rubber track, which can greatly improve the maneuverability of military construction machinery. However, there is almost no effective calculation model for the real-time static steering torque. When the relative sliding speed is greater than 0.01m/s, the influence of friction heating can not be ignored. An improved LuGre

This paper develops electro-elastic relations of functionally graded cylindrical nanoshell integrated with intelligent layers subjected to multi-physics loads resting on elastic foundation. The piezoelectric layers are actuated with external applied voltage. The nanocore is assumed in-homogeneous in which the material properties are changed continuously and gradually along radial direction. Reddy’s

Intentional electromagnetic interference is a serious threat to the safety of electronic devices. Multiple electromagnetic pulses will be coupled and transmitted to electronic devices through the cables. Accumulative effects are generated, which make it easier for damage to occur in the electronic devices. In this article, the working principle of micro-silicon acceleration sensors is introduced. The

Polyurea coating and carbon fibre reinforced polymer reinforcing techniques were applied to retrofit a severely damaged urban utility tunnel (UUT). The blast responses of the retrofitted UUT were investigated through in-filed explosion experimental tests, and the displacements, strains, accelerations, and damage were compared. The retrofitted UUT exhibited comparable or even better blast resistance

In this study, hydrogen-storage glass microballoons were introduced into emulsion explosives to improve the detonation performance of the explosives. The effect of hydrogen-storage pressure on the detonation characteristics of emulsion explosives was systematically investigated. Detonation velocity experiments shows that the change of sensitizing gas and the increase of hydrogen pressure have different

Personal body armour is one of the most important pieces of equipment to protect human beings from various critical and fatal injuries. In today’s modern world, various organizations including law enforcement and security service have made it mandatory for their personnel to wear personal protection system while on field duty. However, the systems should comprise an improved ballistic performance,

The structural performance of perforated steel columns (PSCs) is significantly more complex than the one of solid web I-shaped elements under the diversity of blast loading scenarios. The damage criterion of PSCs is not only related to initial deformation response during the blast but also the residual axial load capacity and it can be considered as a reliable index after the blast effects. Therefore

Ballistic impact and sealed chamber tests were performed on the steel-encased reactive material projectile (SERMP) to understand its behind-plate overpressure effect when impacting the thin aluminum plates. The reactive material encased with a 1.5 mm thick 30CrMnSiNi2A steel shell was launched onto the initially sealed test chamber with a 3mm thick 2024-T3 thin aluminum cover plate. Moreover, the overpressure

A kind of phase change material (PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy propellants. The effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS technology. Due to the delayed protection

The close-in weapon system (CIWS) is a combat system that faces a complex environment full of dynamic and unknown challenges, whose construction and planning require a systematic design method. Multi-living agent (MLA) theory is a methodology for the combat system design, which uses the livelihood degree to evaluate the multi-dimensional long-term operational effectiveness of the system; whereas, there

Multi-element array photoelectric detector is the core devices to form a photoelectric detection target with a large field of view. This photoelectric detection target brings about the problem of uneven detection sensitivity distribution in the detection screen. To improve the uneven detection sensitivity of this photoelectric detection target, this paper analyzes the distribution law of the uneven

In order to maximize the lethality and reversibility of the non-lethal laser weapons (NLLW) at the same time and thus provide a theoretical basis for the R&D of laser weapons in the future, this paper accurately analyzed the limiting biological dose of irreversible damage to human skin caused by the NLLW. Firstly, based on the burn theory in medicine and the actual tactical background, this paper redefines

A layered charge composed of the JH-2 explosive enveloped by a thick-walled cylindrical casing (active aluminum/rubber and inert lithium fluoride/rubber composites) was designed and explosion experiments were conducted in a 1.3 m3 tank and a 113 m3 bunker. The blast parameters, including the quasistatic pressure (ΔpQS), special impulse (I), and peak overpressure (Δpmax), and images of the explosion

Labeling of the connected components is the key operation of the target recognition and segmentation in remote sensing images. The conventional connected-component labeling (CCL) algorithms for ordinary optical images are considered time-consuming in processing the remote sensing images because of the larger size. A dynamic run-length based CCL algorithm (DyRLC) is proposed in this paper for the large

An intersecting cavern is a common structural form used in underground engineering, and its safety and stability performance directly control the service performance of the whole project. The dynamic responses of the three kinds of crossing type (＋-shaped, T-shaped, L-shaped) caverns subjected to ground shock were studied by numerical simulation. The velocity plus force mode boundary setting method

In this research, a promising class of insensitive and high-energy dense biopolymers, which contain nitrogen-rich 1H-tetrazol-1-yl acetate and nitrate ester functional groups, was successfully synthesized through tetrazole derivatization and nitration of cellulose and its micro-sized derivative (TNCN and TCMCN). Their molecular structures, physicochemical properties, thermal behaviors, mechanical sensitivities

The present research introduces a unique concept of scarf joint technique in friction stir welding (FSW) of aluminum alloy AA 6061-T6 plates and an investigation on weld quality. A new joint configuration with two distinct scarf angles (75° and 60°) was considered in this study. The various aspects of welding were compared with contemporary simple square butt (SSB) joint configuration. Welding was

The present study aims at assessing the ballistic impact behaviour of jute reinforced polyethylene glycol (PEG) and nano silica based shear thickening fluid (STF). Preparation of STF is achieved by dispersing the nano silica particles at different weight percentage loadings of 10%, 20%, 30% and 40% in PEG and the effect of various weight percentages loading of nano silica particles on ballistic performance

To improve the feature extraction of ship-radiated noise in a complex ocean environment, a novel feature extraction method for ship-radiated noise based on complete ensemble empirical mode decomposition with adaptive selective noise (CEEMDASN) and refined composite multiscale fluctuation-based dispersion entropy (RCMFDE) is proposed. CEEMDASN is proposed in this paper which takes into account the high

On 13 October 2020, on the fairway connecting the Polish Baltic ports of Świnoujście and Szczecin, an underwater hazardous object of historical origin in the form of the British deep penetration bomb Tallboy dropped during the bombing of the German cruiser "Lützow" in April 1945 was neutralized successfully. It is believed to be the first underwater action concerning this type of bomb, which has previously

Clay brick masonry unit (CBMU) walls are widely used in building structures, and its damage and protection under explosion loads have been a matter of concern in the field of engineering protection. In this paper, a series of full-scale experiments of the response characteristics of 24 cm CMBU walls unreinforced and reinforced with polyurea elastomer subjected to blast loading were carried out. Through

A moving target tracking control problem for marching tank based on adaptive robust feedback control scheme is addressed. A series of preparations is needed for tank gun before shooting a target, the purpose of this paper is to design a control system to fulfill two requirements in this process: the turret-barrel system of tank needs to be adjusted from off-target position to command position and point

Microsatellites have been widely applied in the fields of communication, remote sensing, navigation and science exploration due to its characteristics of low cost, flexible launch mode and short development period. However, conventional solid-propellant have difficulties in starting and interrupting combustion because combustion is autonomously sustained after ignition. Herein, we proposed a new type

Focused energy delivery (FED) is a technique that can precisely bring energy to the specific region, which arouses wide attention in precision electronic warfare (PREW). This paper first proposes a joint optimization model with respect to the locations of the array and the transmitted signals to improve the performance of FED. As the problem is nonconvex and NP-hard, particle swarm optimization (PSO)

This study focusses on establishing the finite element model based on a new hyperbolic shear deformation theory to investigate the static bending, free vibration, and buckling of the functionally graded sandwich plates with porosity. The novel sandwich plate consists of one homogenous ceramic core and two different functionally graded face sheets which can be widely applied in many fields of engineering

In this study, a combined experimental, numerical and theoretical investigation is conducted on the penetration of semi-infinite 4340 steel targets by a homogeneous 93W rod and two types of jacketed rods with striking velocities of 0.9-3.3 km/s. The results show that the jacketed rods produced typical “co-erosion” damage at all test velocities, except for the 93W/1060Al jacketed rod, which switched

This paper considers the problem of target and jamming recognition for the pulse Doppler radar fuze (PDRF). To solve the problem, the matched filter outputs of the PDRF under the action of target and jamming are analyzed. Then, the frequency entropy and peak-to-peak ratio are extracted from the matched filter output of the PDRF, and the time-frequency joint feature is constructed. Based on the time-frequency

The compressive mechanical behavior of composite modified double base (CMDB) propellant was investigated across a wide scope of strain rates ranging from 10-3 s-1 to 4210 s-1 at room temperature, by applying a conventional universal testing machine and a split Hopkinson tension bar (SHPB), respectively. The derived stress-strain curves at different strain rates show a strong rate dependence, indicated

This article deals with the investigation of the effects of porosity distributions on nonlinear free vibration and transient analysis of porous functionally graded skew (PFGS) plates. The effective material properties of the PFGS plates are obtained from the modified power-law equations in which gradation varies through the thickness of the PFGS plate. A nonlinear finite element (FE) formulation for

In low signal-to-noise ratio (SNR) environments, the traditional radar emitter recognition (RER) method struggles to recognize multiple radar emitter signals in parallel. This paper proposes a multi-label classification and recognition method for multiple radar-emitter modulation types based on a residual network. This method can quickly perform parallel classification and recognition of multi-modulation

In this study, a modeling method for investigating the dynamic characteristics of a hydraulically driven shell manipulator with revolute clearance joints is presented. This model accounts for the effect of the clearance, the flexibility of the rotating beam, and the coupled dynamic characteristics of the hydraulic cylinder. A modified contact force model was developed to simulate the physical properties

Heterocyclic skeleton (Azoles) and different energetic groups containing high performing explosives are highly emerged in recent years to meet the challenging requirements of energetic materials in both military and civilian applications with improved performance. For this purpose tetrazole (Azole) is identified as an attractive heterocyclic backbone with energetic functional groups nitro (-NO2), nitrato

Insensitive energetic materials are promising in the defense weapons field. However, energetic materials still suffer from great challenges and the concern about their safety limits their utilization. In this work, insensitive energetic explosive 3,3'-diamino-4,4'-azoxyfurazan/hexahydro-1,3,5-trinitro-1,3,5-triazine (DAAF/RDX) microspheres were fabricated by self-assembly method. Rod-like DAAF/RDX

Game theory can be applied to the air combat decision-making problem of multiple unmanned combat air vehicles (UCAVs). However, it is difficult to have satisfactory decision-making results completely relying on air combat situation information, because there is a lot of time-sensitive information in a complex air combat environment. In this paper, a constraint strategy game approach is developed to

Dome structures have been used extensively for industrial, residential, and military infrastructure. Therefore, it is necessary to understand the damage risk potential for such structures for blast-resistant design considerations. This paper investigates the effect of blast load variability on the design value and the structural dynamic response. Therefore, the sources of uncertainty in the external

Experimental investigation has been carried out for laser ignition and combustion of nanothermites based on aluminum and oxides of copper, bismuth and molybdenum. Ultrasonic mixing of nanosized powders was used to produce compositions. For thermite ignition, initiating laser pulse with a maximum intensity of 770 W/cm2 was generated by a laser diode with a wavelength of 808 nm. The ignition delay times

Magnesium hydride (MgH2) was doped into PTFE/Al to improve the energy release characteristics of the material system and strive for better application in military engineering. Five types of PTFE/Al/MgH2 reactive materials with different MgH2 content were prepared by molding sintering method. The dynamic mechanical properties of the materials were studied by performing split-Hopkinson pressure bar (SHPB)

The armature is an important part affecting the energy conversion efficiency of a reluctance accelerator. In this paper, six kinds of soft magnetic materials are chosen and four structures are designed for the armature. At first, the circuit and magnetic force are theoretically analyzed. Then the armatures with different materials and structures are used in the simulation, and the performances are

To increase launching frequency and decrease drag force of underwater projectiles, a serial multi-projectiles structure based on the principle of supercavitation is proposed in this paper. The drag reduction and supercavitation characteristics of the underwater serial multi-projectiles are studied with computational fluid dynamics (CFD) and machine learning. Firstly, the numerical simulation model

In this paper, a passive muzzle arc control device (PMACD) of the augmented railguns is studied. By discussing its performance at different numbers of extra rails, a parameter optimization model is proposed. Through the calculation model, it is found that the PMACD works well in the simple railgun, which refers to the gun that there is only one pair of rails in the inner bore. The PMACD may decrease

The main objective of this study is to investigate the buckling analysis of CCSs reinforced by CNTs subjected to combined loading of hydrostatic pressure and axial compression resting on the two-parameter elastic foundation (T-P-EF). It is one of the first attempts to derive the governing equations of the CCSs reinforced with CNTs, based on a generalized first-order shear deformation shell theory (FSDST)