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.

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 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.

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 Cylindrical cavity expansion approximations using different constitutive models for the target material

2017 ◽  
Vol 9 (2) ◽  
pp. 199-225 ◽  
Author(s):  
Joakim Johnsen ◽  
Jens Kristian Holmen ◽  
Thomas L Warren ◽  
Tore Børvik
Keyword(s):  
Strain Hardening ◽  
Cylindrical Cavity ◽  
Constitutive Models ◽  
Target Material ◽  
Cavity Expansion ◽  
Ballistic Limit ◽  
Ductile Metals ◽  
Cylindrical Cavity Expansion ◽  
Expansion Theory ◽  
Cavity Expansion Theory

In this article, we investigate the results obtained using different constitutive models for the solution of the cylindrical cavity expansion problem under plane strain conditions. The cylindrical cavity expansion solutions are employed with the cylindrical cavity expansion approximation to obtain ballistic limit and residual velocities for ductile metals perforated by rigid projectiles. Many of the previously developed cylindrical cavity expansion approximations use simplified constitutive models. However, in the present work, we first extend the cylindrical cavity expansion theory with the Voce strain hardening rule, before we utilize three different strain hardening constitutive models in cylindrical cavity expansion calculations to predict ballistic limit and residual velocities of aluminum and steel target plates struck by rigid projectiles. The results show that when strain hardening is accurately represented by the constitutive models until necking in a uniaxial tension test, all cylindrical cavity expansion models predict ballistic limit velocities that are close to the experimental data.

scholarly journals Constitutive modelling of root-reinforced granular soils – preliminary studies

2018 ◽  
Vol 27 (2) ◽  
pp. 103-113
Author(s):  
Barbara Świtała ◽  
E. Fern
Keyword(s):  
Large Scale ◽  
Triaxial Compression ◽  
Constitutive Modelling ◽  
Model Parameters ◽  
Granular Soils ◽  
Compression Tests ◽  
Dune Stability ◽  
Dry Soil ◽  
Triaxial Compression Tests ◽  
Implementation In Matlab

A novel solution for the problem of modelling of soil reinforced with vegetation roots. An extension of the Nor–Sand model and its application to granular saturated or dry, soil–root composites. Model implementation in MATLAB: numerical simulations of drained triaxial compression tests, investigation of the sensitivity of the solution to different values of model parameters. Capturing the most important features of soil–root composites. Accounting for the progressive activation of the root’s strength. Indication of the ability of further model application to large-scale problems, such as slope or dune stability.

An Elastoplastic Model for Granular Materials Exhibiting Particle Crushing

2007 ◽  
Vol 340-341 ◽  
pp. 1273-1278 ◽  
Author(s):  
De An Sun ◽  
Wen Xiong Huang ◽  
Dai Chao Sheng ◽  
Haruyuki Yamamoto
Keyword(s):  
Shear Strength ◽  
Granular Materials ◽  
Triaxial Compression ◽  
Model Performance ◽  
Confining Pressure ◽  
Model Parameters ◽  
Compression Tests ◽  
Particle Crushing ◽  
Wide Range ◽  
Triaxial Compression Tests

A practical elastoplastic constitutive model for granular materials is presented. And the model is suitable for description of the material behaviour for a wide range of stresses, including those sufficient to cause particle crushing. With a limited number of model parameters, the model can predict the confining-pressure dependent stress-strain relation and shear strength of granular materials in three-dimensional stresses, especially of variation of shear strength and dilatancy characteristics due to particle crushing under high confining pressure. The model parameters, which have clear physical meanings, can be determined from the results of isotropic compression test and conventional triaxial compression tests. The model performance is demonstrated for triaxial compression tests of a sand for a wide range of the confining-pressure from 0.2MPa to 8.0MPa.

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.

Parameter estimation approach for particle flow model of rockfill materials using response surface method

2015 ◽  
Vol 04 (01) ◽  
pp. 1550003 ◽  
Author(s):  
Shouju Li ◽  
De Li ◽  
Lijuan Cao ◽  
Zichang Shangguan
Keyword(s):  
Response Surface ◽  
Flow Model ◽  
Triaxial Compression ◽  
Particle Flow ◽  
Model Parameters ◽  
Compression Tests ◽  
Surface Method ◽  
Rockfill Materials ◽  
Inversion Procedure ◽  
Triaxial Compression Tests

Particle flow code (PFC) is widely used to model deformation and stress states of rockfill materials. The accuracy of numerical modeling with PFC is dependent upon the model parameter values. How to accurately determine model parameters remains one of the main challenges. In order to determine model parameters of particle flow model of rockfill materials, some triaxial compression experiments are performed, and the inversion procedure of model parameters based on response surface method is proposed. Parameters of particle flow model of rockfill materials are determined according to the observed data in triaxial compression tests for rockfill materials. The investigation shows that the normal stiffness, tangent stiffness and friction coefficient of rockfill materials will slightly increase with increase of confining pressure in triaxial compression tests. The experiments in laboratory show that the proposed inversion procedure behaves higher computing efficiency and the forecasted stress–strain relations agree well with observed values.

A Simple Unconsolidated Undrained Triaxial Compression Test Emulator

2015 ◽  
Vol 771 ◽  
pp. 104-107
Author(s):  
Riska Ekawita ◽  
Hasbullah Nawir ◽  
Suprijadi ◽  
Khairurrijal
Keyword(s):  
Triaxial Compression ◽  
Measurement Data ◽  
Radial Strain ◽  
Compression Tests ◽  
Viscous Effects ◽  
Axial Pressure ◽  
Strain Stress ◽  
The University ◽  
And Storage ◽  
Triaxial Compression Tests

An unconsolidated undrained (UU) test is one type of triaxial compression tests based on the nature of loading and drainage conditions. In order to imitate the UU triaxial compression tests, a UU triaxial emulator with a graphical user interface (GUI) was developed. It has 5 deformation sensors (4 radial deformations and one vertical deformation) and one axial pressure sensor. In addition, other inputs of the emulator are the cell pressure, the height of sample, and the diameter of sample, which are provided by the user. The emulator also facilitates the analysis and storage of measurement data. Deformation data fed to the emulator were obtained from real measurements [H. Nawir, Viscous effects on yielding characteristics of sand in triaxial compression, Dissertation, Civil Eng. Dept., The University of Tokyo, 2002]. Using the measurement data, the stress vs radial strain, stress vs vertical strain, and Mohr-Coulomb circle curves were obtained and displayed by the emulator.

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