Original Article
Passive defense (detection, decontamination and protection and safety - chemical, biological and nuclear, etc.)
Mohammad Sepehri; mohammad amin abbasi
Volume 4, Issue 1 , April 2025
Abstract
In this article, two important parameters in the discussion of strengthening structures against blast load have been investigated in Abaqus finite element software. In the first step, the type of concrete materials resistant to the blast load and in the second step, the geometric shape of the structure ...
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In this article, two important parameters in the discussion of strengthening structures against blast load have been investigated in Abaqus finite element software. In the first step, the type of concrete materials resistant to the blast load and in the second step, the geometric shape of the structure resistant to the blast load has been investigated. To determine the blast-resistant concrete materials, reinforced concrete design models were subjected to blast load, and finally concrete reinforced with macro steel-micro steel hybrid fibers showed the best resistance against blast load. By reinforcing concrete with macro steel-micro steel hybrid fibers, the amount of concrete damage can be reduced by 70%. Also, to determine the structural form resistant to explosion, two structural forms, cubic and hemispherical, were subjected to the blast load and the results showed that the hemispherical structural form shows more resistance to the blast load. Also, to determine the structural form resistant to explosion, two structural forms, cubic and hemispherical, were subjected to the blast load, and the results showed that the hemispherical structural form shows more resistance to the blast load, and the level of structural damage It is reduced to 49%. Also, two hemispherical structures made with control concrete and macro steel-micro steel composite fibers were subjected to severe blast load and it was found that the use of fibers in this form of structures reduces the vulnerability by 26%.
Original Article
Structure/mechanics of solids/dynamics of solids/vibrations/aeroelasticity/...
Keramat Malakzadeh Fard; Alireza Shahi; Alireza pourmoayed
Volume 4, Issue 1 , April 2025
Abstract
This article examines the design of active isolators using the optimal algorithm (LQR). For this purpose, the dynamic model of the satellite launch vehicle as 6 degrees of freedom has been considered. Because the satellite carrier structure has a shell with reinforced ribs and stringers, Stiffness Calculation ...
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This article examines the design of active isolators using the optimal algorithm (LQR). For this purpose, the dynamic model of the satellite launch vehicle as 6 degrees of freedom has been considered. Because the satellite carrier structure has a shell with reinforced ribs and stringers, Stiffness Calculation Methods(SCM) for reinforced shells were used. Also, to calculate the final frequency of the system, the equations of motion obtained from the dynamic model of the satellite launch vehicle were used. For damp vibrations generated with a vibration amplitude of less than 100 Hz, no method in the research conducted has been proposed. In this research, for the first time, a combined system of passive and active isolators to damp vibrations introduced into the energy supply block was used. The results of the present study show that combining these two systems improves the performance of each of the passive and active systems.In this combination, according to the results obtained by this system, vibrations with a vibration amplitude of less than 50 Hz are damped by up to 88 percent, and vibrations on the energy supply block with a vibration amplitude between 50 and 500 Hz by up to 96 percent are damped.
Original Article
Other related fields
Iman Iman Shafieenejad
Volume 4, Issue 1 , April 2025
Abstract
Background & Purpose: This study introduces an innovative framework for aircraft design that integrates fuzzy logic, metaheuristic optimization algorithms, and three-dimensional Pareto front analysis. In the initial phase, the aircraft’s empty and takeoff weights were calculated using conventional ...
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Background & Purpose: This study introduces an innovative framework for aircraft design that integrates fuzzy logic, metaheuristic optimization algorithms, and three-dimensional Pareto front analysis. In the initial phase, the aircraft’s empty and takeoff weights were calculated using conventional design methods. Fuzzy logic was subsequently employed as a decision-making tool to assess the validity of these estimates. Key design parameters such as wing area and engine thrust were identified using a novel computational methodology.Methodology: The optimization of critical design variables was performed using multiple advanced metaheuristic algorithms, including Harris Hawks Optimization (HHO), Marine Predators Algorithm (MPA), Whale Optimization Algorithm (WOA), and Artificial Bee Colony (ABC). These algorithms simultaneously optimized parameters including empty weight, takeoff weight, stall speed, and flight range. The optimized results, particularly in terms of wing area and engine thrust, were benchmarked against reference models of similar aircraft.Findings: Three-dimensional Pareto fronts were generated for design parameters such as empty weight, takeoff weight, and fuel weight to evaluate key performance indicators including fuel efficiency, payload capacity, flight range, and overall performance. The results demonstrated notable improvements in key aerodynamic and propulsion characteristics.Conclusion: The comprehensive analysis conducted in this study led to the development of an optimized model of a propeller-driven aircraft. The proposed approach resulted in significant enhancements in performance metrics and overall efficiency, validating the effectiveness of the integrated optimization and decision-making framework.
Original Article
Defense mechanics/navigation/control/...
Mehran Mahdi Abadi; Nematollah Ghahremani
Volume 4, Issue 1 , April 2025
Abstract
In this paper, a predictive guidance algorithm for the mid-course phase of a solid-propellant ballistic missile is presented using discrete laguerre functions. Utilizing predictive guidance significantly reduces the missile impact error compared to conventional methods. However, the computational load ...
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In this paper, a predictive guidance algorithm for the mid-course phase of a solid-propellant ballistic missile is presented using discrete laguerre functions. Utilizing predictive guidance significantly reduces the missile impact error compared to conventional methods. However, the computational load for implementation on a flight computer could be a fundamental challenge. For this reason, this research has established and developed a new predictive guidance algorithm based on orthogonal discrete laguerre functions to reduce the computational load while maintaining high accuracy in impact. This approach reduces the parameters describing the predictive guidance law, and the execution time of the algorithm's computations decreases significantly. Through 3D simulation, the impact of using this method for mid-course guidance of a ballistic missile is shown compared to predictive guidance. Additionally, comparing the computational loads of different predictive guidance algorithms demonstrates the advantage of this method in reducing the computational demands.
