Penetration of Aluminum Targets by Ogive-Nosed Projectiles at Oblique Angles

2013 ◽  
Vol 275-277 ◽  
pp. 746-750
Author(s):  
Yu Tao Hu ◽  
Fang Yun Lu ◽  
Bang Hai Jiang ◽  
Duo Zhang
Keyword(s):  
Finite Element ◽  
Free Surface ◽  
Spherical Cavity ◽  
Surface Effects ◽  
Cavity Expansion ◽  
Finite Element Code ◽  
Transient Dynamic ◽  
Dynamic Finite Element ◽  
Spherical Cavity Expansion ◽  
Good Agreement

.In this paper we present the results from a combined experimental, analytical, and computational penetration program. we use an explicit transient dynamic finite element code to model the projectile under an analytical forcing load representing the target. As angle of obliquity is increased free surface effects become significant, The analytical forcing load used here derived from the spherical cavity expansion approach with modifications to account for the free surface effects during oblique penetration. Results from the simulations show the trajectory of the projectile are in good agreement with experiments.

Penetration of Strain-Hardening Targets With Rigid Spherical-Nose Rods

1991 ◽  
Vol 58 (1) ◽  
pp. 7-10 ◽  
Author(s):  
M. J. Forrestal ◽  
N. S. Brar ◽  
V. K. Luk
Keyword(s):  
Closed Form ◽  
Strain Hardening ◽  
Spherical Cavity ◽  
Cavity Expansion ◽  
Rigid Rods ◽  
Engineering Models ◽  
Spherical Nose ◽  
Spherical Cavity Expansion ◽  
Penetration Depths ◽  
Good Agreement

We developed engineering models that predict forces and penetration depth for long, rigid rods with spherical noses and rate-independent, strain-hardening targets. The spherical cavity expansion approximation simplified the target analysis, so we obtained closed-form penetration equations that showed the geometric and material scales. To verify our models, we conducted terminal-ballistic experiments with three projectile geometries made of maraging steel and 6061-T651 aluminum targets. The models predicted penetration depths that were in good agreement with the data for impact velocities between 0.3 and 1.0 km/s.

A Spherical Cavity Expansion Penetration Model for Concrete Based on Hoek–Brown Strength Criterion

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
H. Xu ◽  
H. M. Wen
Keyword(s):  
Spherical Cavity ◽  
Mechanical Response ◽  
Plastic Material ◽  
Strength Criterion ◽  
Cavity Expansion ◽  
Forcing Function ◽  
Basic Features ◽  
Expansion Model ◽  
Spherical Cavity Expansion ◽  
Good Agreement

AbstractA spherical cavity expansion model for concrete is first proposed by using an elastic-brittle-plastic material law with Hoek–Brown strength criterion. The constitutive model can capture the basic features of the mechanical response of concrete materials including the effects of strain-softening and pressure hardening (pressure-dependent shear strength) and all the parameters used in the model can be determined from material tests. The forcing function obtained from the spherical cavity expansion analysis is then employed to construct a penetration model for concrete targets struck by ogival-nosed projectiles. It transpires that the present model predictions are in good agreement with experimental observations in terms of penetration depth and ballistic limits/residual velocities in the case of perforation.

scholarly journals Efficient Method to Evaluate Critical Ricochet Angle of Projectile Penetrating into a Concrete Target

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Min Kuk Choi ◽  
Jihoon Han ◽  
Sangjin Park ◽  
Woo Jin An
Keyword(s):  
Finite Element ◽  
Spherical Cavity ◽  
Cavity Expansion ◽  
Projectile Motion ◽  
Empirical Function ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Semi Empirical ◽  
Spherical Cavity Expansion ◽  
Critical Ricochet Angle

In this study, we propose an efficient computation method to estimate the critical ricochet angle (CRA) for oblique penetration into concrete targets which is based on the spherical cavity-expansion theory. During penetrating event, the resistance force on the projectile nose is approximated by semi-empirical function from the spherical cavity-expansion theory and projectile motion of oblique penetration is predicted to verify the proposed numerical method with the aid of finite differential approach. In order to enhance the accuracy of projectile motion, the empirical constants of the semi-empirical function are obtained with respect to the oblique angle by conducting finite element analyses of the oblique penetration. CRA is then obtained by predicting the projectile motion at the various oblique angles and verified with results of finite element analysis. Our work presents that the reliable CRA can be estimated efficiently by employing a series of the numerical simulations. We believe that our proposed numerical method will provide a useful analysis platform for designing penetrator warhead which hits the target at an oblique impact angles.

A Spherical Cavity Expansion Penetration Model for Concrete Based on Hoek–Brown Strength Criterion

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
H. Xu ◽  
H. M. Wen
Keyword(s):  
Spherical Cavity ◽  
Mechanical Response ◽  
Plastic Material ◽  
Strength Criterion ◽  
Cavity Expansion ◽  
Forcing Function ◽  
Basic Features ◽  
Expansion Model ◽  
Spherical Cavity Expansion ◽  
Good Agreement

AbstractA spherical cavity expansion model for concrete is first proposed by using an elastic-brittle-plastic material law with Hoek–Brown strength criterion. The constitutive model can capture the basic features of the mechanical response of concrete materials including the effects of strain-softening and pressure hardening (pressure-dependent shear strength) and all the parameters used in the model can be determined from material tests. The forcing function obtained from the spherical cavity expansion analysis is then employed to construct a penetration model for concrete targets struck by ogival-nosed projectiles. It transpires that the present model predictions are in good agreement with experimental observations in terms of penetration depth and ballistic limits/residual velocities in the case of perforation.

A Spherical Cavity Expansion Penetration Model for Concrete Based on Hoek–Brown Strength Criterion

2012 ◽  
Vol 13 (2) ◽  
pp. 145-152
Author(s):  
H. Xu ◽  
H. M. Wen
Keyword(s):  
Spherical Cavity ◽  
Mechanical Response ◽  
Plastic Material ◽  
Strength Criterion ◽  
Cavity Expansion ◽  
Forcing Function ◽  
Basic Features ◽  
Expansion Model ◽  
Spherical Cavity Expansion ◽  
Good Agreement

Abstract A spherical cavity expansion model for concrete is first proposed by using an elastic-brittle-plastic material law with Hoek–Brown strength criterion. The constitutive model can capture the basic features of the mechanical response of concrete materials including the effects of strain-softening and pressure hardening (pressure-dependent shear strength) and all the parameters used in the model can be determined from material tests. The forcing function obtained from the spherical cavity expansion analysis is then employed to construct a penetration model for concrete targets struck by ogival-nosed projectiles. It transpires that the present model predictions are in good agreement with experimental observations in terms of penetration depth and ballistic limits/residual velocities in the case of perforation.

scholarly journals Analytical Solutions of Spherical Cavity Expansion Near a Slope due to Pile Installation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Jingpei Li ◽  
Yaguo Zhang ◽  
Haibing Chen ◽  
Fayun Liang
Keyword(s):  
Free Boundary ◽  
Inclination Angle ◽  
Spherical Cavity ◽  
Theoretical Method ◽  
Cavity Expansion ◽  
Sloping Ground ◽  
Present Solution ◽  
Image Technique ◽  
Boussinesq Solution ◽  
Spherical Cavity Expansion

Based on the hypothesis that the penetration of a single pile can be simulated by a series of spherical cavity expansions, this paper presents an analytical solution of cavity expansion near the sloping ground. Compared with the cavity expansion in the half-space, the sloping free boundary has been taken into account as well as the horizontal free boundary. The sloping and horizontal free surfaces are considered by the introduction of a virtual image technique, the harmonic function, and the Boussinesq solution. The results show that the sloping free boundary and the variation of the inclination angle have pronounced influences on the distribution of the stress and displacement induced by the spherical cavity expansion. The present solution provides a simplified and realistic theoretical method to predict the soil behaviors around the spherical cavity near the sloping ground. The approach can also be used for the determination of the inclination angle of the slope according to the maximum permissible displacement.

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