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.

An Investigation on the Nose Mass Abrasion of Projectile

2013 ◽  
Vol 535-536 ◽  
pp. 449-452 ◽  
Author(s):  
Fei Qian ◽  
Hai Jun Wu ◽  
Feng Lei Huang ◽  
Yi Nan Wang
Keyword(s):  
Experimental Data ◽  
Impact Velocity ◽  
Spherical Cavity ◽  
Relative Strength ◽  
Cavity Expansion ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Spherical Cavity Expansion

Based on the dynamic spherical cavity expansion theory of concrete and the analysis of experimental data, a mass abrasion model of projectile considering the hardness of aggregates, the relative strength of target and projectile and the initial impact velocity is constructed in this paper. The initial impact velocity is the most important factor of mass abrasion. The hardness of aggregates and the strength of projectile are also the significant factor of mass abrasion. But relatively speaking, the sensitivity of strength of projectile to mass abrasion is higher, which indicates that the effect of projectile material on mass abrasion is more dramatic than the hardness of aggregates.

scholarly journals Analytical Model for the End-Bearing Capacity of Tapered Piles Using Cavity Expansion Theory

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Suman Manandhar ◽  
Noriyuki Yasufuku
Keyword(s):  
Bearing Capacity ◽  
Cavity Expansion ◽  
Test Results ◽  
End Bearing Capacity ◽  
Proposed Model ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Bearing Behavior ◽  
Spherical Cavity Expansion ◽  
Real Type

On the basis of evidence from model tests on increasing the end-bearing behavior of tapered piles at the load-settlement curve, this paper proposes an analytical spherical cavity expansion theory to evaluate the end-bearing capacity. The angle of tapering is inserted in the proposed model to evaluate the end-bearing capacity. The test results of the proposed model in different types of sands and different relative densities show good effects compared to conventional straight piles. The end-bearing capacity increases with increases in the tapering angle. The paper then propounds a model for prototypes and real-type pile tests which predicts and validates to evaluate the end-bearing capacity.

Mechanism of High-velocity Projectile Penetration into Concrete

2012 ◽  
Vol 13 (2) ◽  
pp. 137-143
Author(s):  
Hai-Jun Wu
Keyword(s):  
Yield Criterion ◽  
Triaxial Compression ◽  
Target Material ◽  
Cavity Expansion ◽  
Model Parameters ◽  
Compression Tests ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Triaxial Compression Tests ◽  
Spherical Cavity Expansion

Abstract The penetration depth of rigid projectiles is investigated using the modified spherical cavity expansion theory and the Holmquist–Johnson–Cook (HJC) model for the concrete targets, in which the model parameters used in the Mohr–Coulomb Tresca-limit yield criterion are obtained by the triaxial compression tests. By comparing the cavity expansion pressures of the concrete samples with two different types of aggregate, the influence of the aggregate hardness on the penetration processes is discussed. With the analysis of the tractions acted on the projectile nose, the influences of the projectile and target material properties as well as the projectile structure on the transition impact velocity are also discussed. By comparing the theoretical results with the experimental data, two penetration mechanisms are demonstrated for the ogive-nose projectile penetration into concrete with the striking velocities up to 2.0 km/s.

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.

Mechanism of High-velocity Projectile Penetration into Concrete

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
Hai-Jun Wu ◽  
Yinan Wang ◽  
Yu Shan ◽  
Feng-Lei Huang ◽  
Qing-Ming Li
Keyword(s):  
Yield Criterion ◽  
Triaxial Compression ◽  
Target Material ◽  
Cavity Expansion ◽  
Model Parameters ◽  
Compression Tests ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Triaxial Compression Tests ◽  
Spherical Cavity Expansion

AbstractThe penetration depth of rigid projectiles is investigated using the modified spherical cavity expansion theory and the Holmquist–Johnson–Cook (HJC) model for the concrete targets, in which the model parameters used in the Mohr–Coulomb Tresca-limit yield criterion are obtained by the triaxial compression tests. By comparing the cavity expansion pressures of the concrete samples with two different types of aggregate, the influence of the aggregate hardness on the penetration processes is discussed. With the analysis of the tractions acted on the projectile nose, the influences of the projectile and target material properties as well as the projectile structure on the transition impact velocity are also discussed. By comparing the theoretical results with the experimental data, two penetration mechanisms are demonstrated for the ogive-nose projectile penetration into concrete with the striking velocities up to 2.0 km/s.

Mechanism of High-velocity Projectile Penetration into Concrete

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
Hai-Jun Wu ◽  
Yinan Wang ◽  
Yu Shan ◽  
Feng-Lei Huang ◽  
Qing-Ming Li
Keyword(s):  
Yield Criterion ◽  
Triaxial Compression ◽  
Target Material ◽  
Cavity Expansion ◽  
Model Parameters ◽  
Compression Tests ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Triaxial Compression Tests ◽  
Spherical Cavity Expansion

AbstractThe penetration depth of rigid projectiles is investigated using the modified spherical cavity expansion theory and the Holmquist–Johnson–Cook (HJC) model for the concrete targets, in which the model parameters used in the Mohr–Coulomb Tresca-limit yield criterion are obtained by the triaxial compression tests. By comparing the cavity expansion pressures of the concrete samples with two different types of aggregate, the influence of the aggregate hardness on the penetration processes is discussed. With the analysis of the tractions acted on the projectile nose, the influences of the projectile and target material properties as well as the projectile structure on the transition impact velocity are also discussed. By comparing the theoretical results with the experimental data, two penetration mechanisms are demonstrated for the ogive-nose projectile penetration into concrete with the striking velocities up to 2.0 km/s.

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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