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Open Access Issue
Coupling effects of multi-axles interconnected hydropneumatic suspension of launch vehicle
Journal of National University of Defense Technology 2023, 45(4): 153-161
Published: 28 August 2023
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Heavy missile launchers mostly use 4-axles linked dual-chamber HPS (hydropneumatic suspension), in order to study their linkage coupling effect for the reference of launcher design. The simulation models of an interconnected HPS of two-axles and four-axles were built based on the mathematic model and AMESim software. Based on this, the influence of the coupling effect of the multi-axles connected twin-accumulator HPS system was analyzed under several different excitation frequencies. The results show that even under low-frequency excitation, the multi-axis interconnected HPS has obvious damping characteristics. Compared with the two-axles interconnected HPS system, the external characteristics of the four-axles interconnected HPS system have advantages. The external characteristics of the connected HPS system are more intense when excited by low frequency and good when excited by high frequency, indicating that the system can attenuate the asynchronous vibration of the system when it is in a high frequency environment.

Open Access Issue
Ballistic performance of double-arrow negative Poisson′s ratio structure
Journal of National University of Defense Technology 2023, 45(2): 197-207
Published: 28 April 2023
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The penetration performance of the double-arrow negative Poisson′s ratio multicellular structure against bullet penetration was studied by numerical simulation method. The penetration behaviors of bullets and the damage forms of the double-arrow negative Poisson′s ratio structure under the three bullet target conditions of top-edge impact, hinge-point impact and side-impact were compared and analyzed. The results show that the negative Poisson′s ratio effect of the double-arrow negative Poisson′s ratio structure is not significant when the bullet impacts the structure at a high velocity. The bullet directly penetrates the structure at topside impact and hinge point impact, the damage of the cell element is small and the anti-intrusion performance of the double-arrow negative Poisson′s ratio multi-cell structure is poor at this time. The bullet does not penetrate the multi-cell structure at side impact, and the damage of the cell element is large; the double-arrow negative Poisson′s ratio structure relies on its double-Poisson′s ratio structure to deflect the bullet at side impact. The double-arrow negative Poisson′s ratio structure relies on its double triangular structure to deflect and roll the bullet during side impact, which significantly increases its penetration resistance. The effect of the change in the angle of incidence of the bullet during topside impact on the intrusion resistance of the double-arrow negative Poisson′s ratio structure was analyzed. It is found that there is a 30° angle of incidence and a 60° angle of incidence. The double-arrow negative Poisson′s ratio multi-cell structure has some resistance to penetration when the bullet is near these two incidence angles.

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