جستجوی مقالات مرتبط با کلیدواژه « shaped charge » در نشریات گروه « مکانیک »

Discrete concrete targets show more resistance to penetration against shaped charges. The purpose of this study is to simulate the penetration of shaped charge in discrete concrete targets using LS-DYNA and ANSYS-AUTODYN and compare the results. For this purpose, the simulation process for one of the experimental results is performed and the results obtained from both software are validated. Finally, the results of two software in the fields of jet velocity, penetration depth, entry diameters, middle and exit crater, and run time are compared. Application of the ALE method for jet elements and the RHT concrete model to simulate the concrete behavior at high strain rates yielded good results. Differences in numerical solution method and command differences in the interaction of the Lagrangian and Eulerian elements in two software caused the depth of penetration in ANSYS-AUTODYN to be less than the LS-DYNA and the diameters of entry, middle and exit crater in ANSYS-AUTODYN become larger than the LS-DYNA and closer to the experimental results. The results of the two software are in good agreement with the experimental results. Continuous concrete was also simulated and it was found that the penetration depth of discrete concrete was lower than continuous concrete.

One of the main important components which are used in the shaped charges is liner that its material has a considerable influence on the jet formation and penetration profile. In recent years, researches have focused on the analysis of the effect of bimetallic liners and their effective behavior. In this paper, at the first step, the process of jet formation and the penetration in the steel target is numerically simulated for a shaped charge with copper liner using the Ansys-Autodyn software. Analytical solutions have been done using generalized PER theory for jet formation and hydrodynamics theory for penetration; as well the experimental tests were performed with copper liner. The comparison of penetration profiles obtained from numerical, experimental and analytical methods showed a good agreement. Then, the validated numerical simulations were developed for two single-metal liners of nickel and aluminum, and two bimetallic copper-nickels, and copper-aluminum liners. Also, the results of jet tip velocity, penetration depth and crater diameter have been compared between single and bimetallic liners. Regarding to jet formation and penetration in steel target, the comparison between single and bimetallic liners results shows that the using bimetallic liners, improve crater diameter and depth of penetration simultaneously.

of the main important components which are used in the shaped charges is liner that its material has a considerable influence on the jet formation and penetration profile. In recent years, researches have focused on the analysis of the effect of bimetallic liners and their effective behavior. In this paper, at the first step, the process of jet formation and the penetration in the steel target is numerically simulated for a shaped charge with copper liner using the Ansys-Autodyn software. Analytical solutions have been done using generalized PER theory for jet formation and hydrodynamics theory for penetration; as well the experimental tests were performed with copper liner. The comparison of penetration profiles obtained from numerical, experimental and analytical methods showed a good agreement. Then, the validated numerical simulations were developed for two single-metal liners of nickel and aluminum, and two bimetallic copper-nickels, and copper-aluminum liners. Also, the results of jet tip velocity, penetration depth and crater diameter have been compared between single and bimetallic liners. Regarding to jet formation and penetration in steel target, the comparison between single and bimetallic liners results shows that the using bimetallic liners, improve crater diameter and depth of penetration simultaneously.

The aim of this paper is simulation of shaped charge process using Eulerian analysis. To this end, the finite element analysis was used to simulate the process of shaped charge. In this simulation, whole of the model has been considered from Eulerian elements. Verification of finite element method has been confirmed by comparing simulation with experimental tests and Birkhoff model. Comparison of penetration depth in finite element analysis with experimental samples has shown that the results are in good agreement with each other. Also comparing parameters such as liner collapse velocity, velocity distribution in jet length and jets profile has indicated that the simulation results are close to Birkhoff model. It should be noted that ABAQUS finite element software is used in this simulation to analyze the process of shaped charge.

Oil well perforators (OWP) are explosive devices that are used in drilling industries of oil and gas wells to access the reservoir and increase the wells efficiency. Oil well perforators performance is measured by the depth of penetration that can cause, for this reason depth as the main parameter must be examined. In this article, a complete report of numerical simulation and performance optimization of these devices, which are indeed small sizes shaped charges, is presented. To do this, the multi-material eulerian and the lagrangian methods are used for simulation of the jet formation and its penetration into underground rock processes, respectively. For solving the problem of large deformation elements in lagrangian method, erosion criterion elements were used. Because the results of jet formation and penetration Process heavily influenced by the density of the mesh, In this study mesh sensitivity were examined.. Described simulation, is validated by the use of reliable results of some references and then, a new charge geometry is suggested which resolves the inhomogeneities in the distribution velocity of the tail and increases the effective length of jet in the penetration process.