聚能射流侵彻

Advanced Materials Research Vols. 148-149 (2011) pp 744-748 Online available since 2010/Oct/27 at © (2011) Trans Tech Publications, Switzerland doi:10.4028//AMR.148-149.744
Fig.3 The numerical model in simulation Material Models. In calculation model, the shell of charge is 45 steel while the liner material respectively are titanium alloy, mild steel and Cu, Johnson-cook material model is adopt to simulate the dynamic response of material with large deformation under high strain rate and temperature changing. The main stress is: (1) ó = ( A + Bε n )(1 + c ln(ε * )(1 − (T *)m ) Here, σ is dynamic yield stress, εn is effective plastic strain, ε* is effective plastic strain ratio, T* is correlation temperature, A is static yield stress, B is strain hardening coefficient, c is correlation coefficient of strain rate, m is correlation coefficient of temperature. The explosive charge is Comp. B, and JWL EOS was employed to describe the explosive detonation and energy release process, it assumes the detonation front spreads at constant speed. The detonation products pressure p is
Advanced Materials Research Vols. 148-149
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Fig.1 Schematic model of shaped charge
Fig.2 Schematic model of multi-layer target
Numerical Model. During the jet formation and penetration into multi-layer process, liner is crushed by detonation products, while the concrete of multi-layer is shear damaged. All relative material has serious deformation. With a purely Lagrange or Euler algorithm cannot describe the whole action process accurately. So this paper uses the Euler-Lagrange coupling algorithm which coupling calculates the jet formation and penetration into multi-layer process. The simulation model is created (see Fig. 3), the shaped charge was meshed in Euler area while the multi-layer model was created use Lagrange grid with local refined mesh size. Problem in present paper is considered as symmetric, the shaped charge and target is half modeled. To show the free expanding of detonation products, the flow out boundary was defined at the edge of Euler area. Gauge A is defined to get the stress variation of surface concrete which penetrated by the jet. The standoff Sd is 0.8 Dk.
Numerical Study of Shaped Charge Jet Formation and Penetration into Multi-layer with Different Liner Material Yan long Kang a, Jian wei Jiang b, Shu you Wang, Jian bing Men
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, . (ID: 138.253.100.121, University of Liverpool, Sydney Jones Library, Liverpool, United Kingdom-29/08/13,08:30:00)
(State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, BeiBiblioteka ing 100081, China)
a
kangyanl@, bbitjjw@
Keywords: liner material; shaped charge; titanium alloy; numerical simulation;
Abstract. This paper investigates the penetration performance of shaped charge against multi-layer target. A titanium alloy liner of shaped charge is proposed in order to obtain large perforated hole. Jet formation and penetrating into multi-layer target was calculated by hydro code AUTODYN. For different liner material include titanium alloy, mild steel and Cu, the explosion energy conversion, jet tip velocity and jet length, also the penetration performance are studied. It is found that the kinetic energy of jet is larger and the shape of jet is podgier when the liner material is titanium alloy, the perforated hole diameter on multi-layer improved 20% compare with the mild steel and Cu liner, the numerical simulation is good agreement to experimental results. Introduction The anti-runway munitions is one kind of effective mean to attack the hard multi-layer target such as airport runway, which makes use of front shaped charge to produce perforated hole with the later following warhead and following blasting. How to make a large perforated hole produced by front shaped charge is the important problem in order to ensure the later warhead following up. Through changing the liner cone angle, liner thickness and the type of explosive charge can improve the diameter of perforated hole to a certain extent but is not enough. Currently, research [1,2] on liner material make it possible to study the large perforated hole in hard target. Although mild steel and Cu liner can make greater penetration performance as the large depth, the lack of diameter can not produce big perforated hole. Some scholars succeed in producing a big perforated hole by means of research on liner with energetic material[3]. However, there are some difficult problems on complex manufacturing processes. This paper presents an approach of producing a big penetrating hole on multi-layer by using titanium alloy liner. The numerical simulation on jet formation and penetration into target by shaped charge which uses titanium alloy, mild steel and Cu liner are studied in AUTODYN [4]. Comparing and analyzing the differences of energy conversion, tip vilocity and length of jet on each liner material. The differences of perforated hole diameter is validated by experiment. The conclusions can be the references of anti-runway warhead engineering designs. Calculation Model Structure Model. The model of shaped charge is a typical structure as shown in Fig. 1. It consists of liner, explosive charge and shell. The charge diameter Dk is 130 mm, the length to diameter ratio L/D is 0.8 and the shell thickness σ1 is 0.025 Dk. The liner is hemispherical shape and variable shell thickness. The top liner thickness σ2 is 0.045 Dk. The detonation point is at the bottom of the explosive charge. Fig. 2 is the simplified model of the multi-layer structure [5]. It consists of surface concrete, base surface poor concrete and bottom surface soil. The surface thickness is 350mm and the base surface thickness is 250mm.