Multi-Stage Multidisciplinary Design Optimization Method for Enhancing Complete Artillery Internal Ballistic Firing Performance

To enhance the comprehensive performance of artillery internal ballistics—encompassing power,accuracy,and service life—this study proposed a multi-stage multidisciplinary design optimization(MS-MDO)method.First,the comprehensive artillery internal ballistic dynamics(AIBD)model,based on propellant combustion,rotation band engraving,projectile axial motion,and rifling wear models,was established and validated.This model was systematically decomposed into subsystems from a system engineering perspective.The study then detailed the MS-MDO methodology,which included Stage I(MDO stage)employing an improved collaborative optimization method for consistent design variables,and Stage II(Performance Optimization)focusing on the independent optimization of local design variables and performance metrics.The methodology was applied to the AIBD problem.Results demonstrated that the MS-MDO method in Stage I effectively reduced iteration and evaluation counts,thereby accelerating system-level convergence.Meanwhile,Stage II optimization markedly enhanced overall performance.These comprehensive evaluation results affirmed the effectiveness of the MS-MDO method.

An Uncertainty Analysis Method for Artillery Dynamics with Hybrid Stochastic and Interval Parameters

This paper proposes a non-intrusive uncertainty analysis method for artillery dynamics involving hybrid uncertainty using polynomial chaos expansion(PCE).The uncertainty parameters with sufficient information are regarded as stochastic variables,whereas the interval variables are used to treat the uncertainty parameters with limited stochastic knowledge.In this method,the PCE model is constructed through the Galerkin projection method,in which the sparse grid strategy is used to generate the integral points and the corresponding integral weights.Through the sampling in PCE,the original dynamic systems with hybrid stochastic and interval parameters can be transformed into deterministic dynamic systems,without changing their expressions.The yielded PCE model is utilized as a computationally efficient,surrogate model,and the supremum and infimum of the dynamic responses over all time iteration steps can be easily approximated through Monte Carlo simulation and percentile difference.A numerical example and an artillery exterior ballistic dynamics model are used to illustrate the feasibility and efficiency of this approach.The numerical results indicate that the dynamic response bounds obtained by the PCE approach almost match the results of the direct Monte Carlo simulation,but the computational efficiency of the PCE approach is much higher than direct Monte Carlo simulation.Moreover,the proposed method also exhibits fine precision even in high-dimensional uncertainty analysis problems.

Dimension-contraction transform for the simulation of fire control system of artillery

A fire control system of artillery includes a photo-tracker, a computing subsystem and a servomechanism. The photo-tracker outputs moving characteristics of the target during the tracking process, and basing upon this, the computing subsystem makes the computation and outputs shooting elements, and the servo-mechanism controls this piece of artillery to point to the foregoing position of its target in terms of the latter elements.

The dynamic response of a high-density polyethylene slow-release structure under launching overload

Based on the 60 mm artillery grenade,a slow-release structure was designed to reduce the severity of ammunitions response to accidental thermal stimulation and improve the thermal stability of ammunitions.The slow-release structure was made of high-density polyethylene(HDPE) and connected the fuse and the projectile body through internal and external threads.To study the safety of the slowrelease structure under artillery launching overload,mechanical analysis of the slow-release structure was simulated via finite element analysis(FEA).The impacts of various factors(e.g.,fuse mass,number of threads,and nominal diameter of internal threads of the slow-release structure) on the connection strength of the slow-release structure were studied.A strength-prediction model based on the fuse mass and internal thread parameters was established by fitting the maximum effective stress of the slowrelease structure.This led to good prediction results.In conclusion,this study provides references and theoretical support for the design of thermal protection structures insensitive to ammunition.

The Tower of Nisida as centre of 17^(th)century fortified naples system

The paper investigates the territorial layout of the fortified system of Naples that developed during the Spanish Vice Kingdom in the 16th-17th centuries.Both existing castles and towers,and constructions built for the purpose,were included in the system.The Tower of Nisida is one of the existing ancient towers that became part of the impressive 17th century defense system of Naples.The study focus is on the strategic importance acquired by Nisida and its Tower in those years,when it became a key location in the fortified system,both evidencing its cruciality through the study of the field of vision that widens from the location and dealing the issue with the point of view landscape and territorial defense,recalling the concept that the defense architecture is part of architectural heritage.