Blast shock wave is a strong intermittent load produced by explosive explosion, which is a main harmful factor causing direct damage to human brain, lung and other gas-bearing organs. For an explosion-proof equipment made of two typical materials, the static explosion tests and numerical calculations of various TNT charges were carried out to study the attenuation law of shock wave propagation under three different protection conditions of free air burst (FAB), steel explosion-proof (SEP) and flexible explosion-proof (FEP). The response process and protection mechanism of two typical explosion-proof equipment are analyzed, and the empirical model of weakening the shock wave overpressure peak for the protection of typical equipment is obtained. The research shows that SEP and FEP can significantly reduce the internal blast shock wave load. Compared with FAB at the same location, SEP reduces the peak overpressure of shock wave by 55.4%~66.3%, and FEP reduces the peak overpressure by 57.2%~77.7%. The shock wave protection ability of FEP is obviously higher than that of SEP during over-equivalent explosion. The main protection mechanism of SEP and FEP is diffraction shielding, but the FEP roof increases the time of interaction between the shock wave and the structure, and weakens the intensity of escaping shock wave through the momentum extraction effect of water and the interface reflection of different wave impedances, while the shock wave in SEP escapes quickly after reflectiing through the rigid materials. The average errors of SEP and FEP shock wave peak overpressure attenuation models are 2.4% and 10.2%, respectively. The shock wave weakening law and protection experience model of typical equipment obtained in this paper are expected to provide reference for the design of explosion-proof tank equipment.

Traditional combat network models struggle to reflect interaction dynamics between combat parties and often neglect practical node deletion strategies. Additionally, system capability quantification often relies excessively on the number of kill chains. To address these issues, this paper proposes a system combat capability analysis method based on an interactive adversarial network model. The paper establishes a red-blue interactive network model that incorporates both combat nodes into the network model, and suggests updating both nodes through a reachable node deletion strategy. It introduces the concepts of kill chain capability and system kill chain capability, and quantifies the system combat capability based on the scale of destruction. To account for the complexity of calculating two-terminal connectivity in unequal probability networks, this paper uses Monte Carlo simulation to solve the system kill chain capability. Simulation experiments analyze key variables affecting the system combat capability and validate the analysis with other methods. The results show that the enhancement of the functional capability of the accusation node is the core key of the combat system, which plays an important role in the non-linear enhancement of the combat destruction capability of the own system and the non-linear suppression of the enemy system, and the simulation comparison experiments verify the superiority of the method in this paper.

Aramid fabrics are widely used in the field of body armors due to their low density, high modulus and high strength. In order to improve the ballistic resistance of aramid fabrics, the aramid fabrics are modified by planting and growing the nano-ZnO particles. The electron microscope observation, quasi-static tensile test, yarn pull-out test, ballistic impact test and numerical simulation were made for ZnO-modified fabrics, and their mechanical and ballistic properties were studied. The results show that the planting of ZnO particles increases the structural interlock and surface roughness of yarns. Compared with the neat fabrics, the inter-yarn friction coefficient of ZnO-modified fabrics is increased by 282%, their ballistic limit velocity is increased by 54.5%, and their energy absorption and specific energy absorption performance are significantly better than those of neat fabrics. The ballistic impact process of the modified fabric is simulated by the meso-yarn model. The simulated results are in good agreement with the ballistic test results. This further explains that the improvement of inter-yarn friction coefficient and tensile strength is an effective means to enhance the ballistic impact resistance of fabrics, and provides a theoretical basis for the application of ZnO-modified fabrics in the field of flexible bulletproof.

This paper investigates the effects of the physical properties on the microstructure and weldability of explosive welding by joining two metals with a significant contrast in thermophysical properties: stainless steel and copper. Sound welds between stainless steel and copper were obtained, and the interfacial morphology was wavy, regardless of the position of the materials. The weldability of dissimilar pairs was found to be more dependent on the relationship between the physical properties of the base materials than on the absolute value of the material property. When there is a significant difference in thermal conductivity between the flyer and the base plate, together with a material with a low melting temperature, the weldability of the pair is often poor. The relative position of the plates affects the interfacial microstructure even when similar morphologies are found. For the metallic pairs studied, the wave size was bigger for the configuration in which the ratio between the density of the flyer and the density of the base plate is smaller. The same phenomenon was observed for the impedance: bigger waves were found for a smaller ratio between the impedance of the flyer and the impedance of the base plate. © 2022 China Ordnance Society

Hydroxyl-terminated polybutadiene/toluene diisocyanate (HTPB/TDI) system is widely used in composite solid propellants. The migrations of plasticizers and water molecules from solid propellants and surrounding environment to the inhibitor have always been the important issues. This study focuses on the preparation, characterization and anti-migration behavior of graphene oxide (GO)/HTPB nanocomposite liner. The GO/HTPB (GH) composite liners affect the migration of small molecules through a tighter cross-linked structure and weakening function of small molecule adsorption. The anti-migration performance of the liner at different temperatures was analyzed, and the influence of the added amount of GO on the anti-migration performance and adhesion performance was also systematically studied. The overall performance of the liner is optimized when the amount of GO filler is 0.3 wt%. After adding 0.3 wt% GO, the concentration of dioctyl sebacate (DOS) migrated into the liner is decreased by 23.28%, and the concentration of water molecules is decreased by 51.89%, indicating that the introduction of GO can significantly improve the anti-migration performance of the liner. In addition, the bond strength is greatly increased from 0.25 MPa to 0.95 MPa, which meets the application requirements of the current propellant system. This research provides an important way for the preparation of structure-function synergistic anti-migration composite liners. © 2021 China Ordnance Society

Metamaterial based on local resonance has excellent vibration attenuation ability in low frequency. In this research, an attempt was performed to make meta-mortar with spring-mass resonators to attenuate vibration and shock hazards. Single-spring-mass resonators and dual-spring-mass resonators were designed and made using lead or aluminum blocks and SWPB springs encased by PMMA (polymethyl methacrylate) or aluminum frames. These resonators were placed into mortar blocks to make meta-mortar specimens. Vibration attenuation effect was investigated by sweeping vibration with frequency from 50 Hz to 2000 Hz. All these meta-mortar blocks exhibit excellent vibration attenuation ability in the designed band gaps. With dual-spring-mass resonators, meta-mortar blocks have two distinct vibration attenuation bands. © 2022 China Ordnance Society

Suitability of S-Glass/carbon fiber reinforced polymer composite for submarine hull subjected to hydrostatic pressure has been investigated in the present study. Metallic materials have raised concerns owing to their decomposition due to low resistance towards salinity and hence polymer composites have been explored to showcase their mechanical stability to withstand transverse and impact loads. To this end, the mechanical properties of S-Glass/carbon fiber reinforced polymer composite were experimentally investigated and higher specific strength and stiffness of the composite in comparison to many metallic materials used for submarine hull were reported. The obtained experimental values were used for the static and dynamic crash analysis of the bow, stern and foil through Finite Element Analysis (FEA); where depth of travel was varied from sea surface level of 0–7000 m. Submarine assembly was later developed with the optimum shape and thickness of each part. We also report the nonlinear crash analysis upon impact at velocity ranging from 3 to 21 m/s. Besides, kinetic energy, acceleration peak and internal energy in struck submarine revealed that travel depth 1750 m and 3500 m is recommendable, more particularly, crash safety factor of the submarine is found to be within limit when submarine encounters crash at 1750 m. © 2022 China Ordnance Society

The modern automatic loading system for large caliber guns involves the collaborative control of multiple motors. The application of sensorless technology can significantly improve the reliability of driving systems. The rotor position identification of surface-mounted permanent-magnet synchronous motor at zero-/low-speeds is a difficult problem in sensorless control. To deal with it, an extended Kalman filter based on mechanical motion model is proposed to assist rotor position estimation. At the same time, the observer disturbance rejection technology is employed to eliminate the influence of disturbances such as model parameter uncertainty to rotor position identification, and to realize reliable start-stop control under zero/low speeds and heavy loads. The proposed method overcomes the limitation of the conventional rotor position estimation method based on the electrical model, greatly improves the load capacity of the sensorless technology at zero/low speeds, and realizes the performance comparable to that of the position sensor servo. This sensorless motor control technology is applied to the 155 mm gun loading system. Finally, the technology is verified by the operation simulation of the modular explosive loader and projectile loader as examples.

The semi-control of the frequency adaptive magnetorheological elastomer(MRE) torsional vibration absorber is a key step to reduce torsional vibration in the powertrain system. In this paper, aiming at the powertrain system of a tracked vehicle, a dynamic system model with a MRE variable stiffness torsional vibration absorber is established. Based on the model, a control strategy combining transient look-up table and steady-state optimization is proposed to significantly reduce the deviation of the identified external excitation dominant frequency, allowing the absorber to be capable of quickly following the dominant external excitation frequency, thereby achieving semi-active control of the vibration absorber. The simulation and experimental results indicate that the proposed integrated control scheme can improve damping performance by 10%.

To explore the effect of different positions and number of pyrrolidine bound to the carbon cage on the stabilization effect of fulleropyrrolidine derivatives to nitrocellulose (NC)/nitroglycerine (NG), we synthesized N-(4-methoxy) phenylpyrrolidine-C60 and four different of bis(N-(4-methoxy) phenylpyrrolidine)-C60 compounds through Prato reaction. Their structures were characterized by UV–vis, 1H NMR, 13C NMR, high-resolution mass spectroscopy, and single-crystal X-ray diffraction. Their stabilization effect to NC/NG were investigated using differential scanning calorimetry, methyl violet, vacuum stabilization effect, weight loss, and accelerating rate calorimeter tests. The results indicated these compounds had excellent stabilization effect to NC/NG. The stabilization effect of the fulleropyrrolidine bisadducts to NC/NG is significantly better than that of fulleropyrrolidine monoadduct and C60. Moreover, the position where pyrrolidine binds to fullerene in fulleropyrrolidine bisadducts is different, and its stabilization effect to NC is also different. The stabilization effect order of different bisadduct isomers to nitrocellulose is as follows: e-edge > trans-2> cis-2> trans-3. Electron paramagnetic resonance (EPR) and FT-IR were used to study the stabilization mechanism of fulleropyrrolidine derivatives to NC/NG. The EPR results also show that fulleropyrrolidine bisadducts with different addition sites have different abilities to absorb nitroxide, and their ability is better than that of the monoadduct and C60, which is consistent with the results of stabilization effect performance test. © 2021 The Authors