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Simulation and analysis of the projectile impact and penetration problem and its effects are among the practical topics that can be used to design bulletproof panel and military equipment, construction of impact and penetration resistant structures, design of projectiles with appropriate penetration strength and high performance noted. One of the most important parameters affecting penetration is the impact velocity of the projectile. The mechanism of penetration varies in different speed ranges. In this paper, Ansys Autodyn software is used for penetration simulation. The simulation carried out in this study is based on the accuracy and physical conditions of the problem and the compatibility of numerical simulation with the governing analytical relations indicates the validity and accuracy of the assumptions made in the simulation. In this study, we selected materials such as material behavior, grating, contact surfaces, and controls, as well as collision of the blunt projectile with angles of 0º,15º,30º,45º by of high velocity impact 1000 m/s with the same mass and diameter and shape of the projectile nose and properties. Ceramic materials are discussed. The result of the numerical simulation comparison shows relatively good agreement between them. [ABSTRACT FROM AUTHOR]

The paper deals with composite structures in the field of advanced and modern structures in engineering design and according to high specification of composite materials such as high strength to weight ratio use in various industries such as aerospace, marine. One of the most important fields that Researchers have paid less attention to that is to investigate the effect of stacking sequence on the strength of mechanical joints under impact loading. In view of changing the mechanical properties of composite materials by changing the arrangement of layers, in this study, the effect of different orientation of layers on the strength of pin joints in glass-epoxy composites under low-velocity tensile impact has been investigated. Using the Abaqus software and the finite element method, the impact simulation and the force applied to the mechanical joint were analyzed. To evaluate the simulations, the results of the finite element method have been compared with the experimental results. By observing the results, the introduced finite element model is well-considered and is well-matched with the result of the experimental dataset, which made it a valuable tool for predicting the strength of multi-layer composite materials under impact loadings. Using the results of the model, one can analyze the distribution and type of stress and strain in each layer of composite. [ABSTRACT FROM AUTHOR]

Balance is one of the most significant and commonly used measurement instruments in wind tunnels. It is thus critical that this instrument is fault-tolerant and reliable. To help in the design of dependable balance systems, one must model and analyze the system from this perspective. We achieved this by considering the structure of a typical balance system and the types of errors it may encounter during operation. We estimated the failure rates of the components of the balance system, such as the balance structure, strain gages, and power supply, using manufacturer technical documents and fatigue tests, and identified the effect of each component on the reliability of the balance system. On this basis, we presented a Markov model for the reliability of the balance system, assuming that the data acquisition of a typical flying model should be complete in less than 15 min in order for the balance system to be considered reliable. Simulation of the proposed model with SHARPE software showed that if we reduced the time of the experiments from 30 min to 15 min, the reliability of the balance system improved by about 30%. In addition, the cost of the experiments in the wind tunnel was reduced by 20%-30%. [ABSTRACT FROM AUTHOR]

In this article a new parameter is introduced that optimizes penetration depth of a long rod penetrating into a semi-infinite target. This parameter helps to optimize penetration depth when the projectile is subjected to transverse loading. This parameter is defined using a simple assumption governing bending moment and deflection of the rod as well as the experimental observation of long rod penetrators having aspect ratios (L/D) of greater than 30. In this article the length of the rod that sustains allowable bending stress but does not fail is calculated. Using the results of the bending analysis and solution of the Alekseevskii & Tate (AT) equation, an analytical method to optimize crater depth for long rod penetrators of L/D > 30 is obtained. The result of the optimization shows a 14% increase in penetration depth. Also the results of the optimization are compared with the experimental results. [ABSTRACT FROM AUTHOR]

Penetration of projectile into concrete target is of high interest to both civilian as well as applied scientists. The penetration process is highly complex and due to it interdisciplinary nature, most of the works in this respect are experimental. High cost of experimentation has forced many of the investigators to rely on simple analytical and engineering models. Recent investigations rely heavily on simulation processes using available software tools. The aim of this paper is to simulate the penetration of a high velocity ogive-shape nose steel projectile into concrete target. The crater depth is also obtained using analytical formula developed by Forrestal. The results of the analytical as well as LS-DYNA simulation are compared with the experimental results of valid sources and a very good agreement is recorded. [ABSTRACT FROM AUTHOR]