scholarly journals Study on Model of Penetration into Thick Metallic Targets with Finite Planar Sizes by Long Rods

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Juan Wang ◽  
Junhai Zhao ◽  
Jianhua Zhang ◽  
Yuan Zhou
Keyword(s):  
Penetration Depth ◽  
High Speed ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Cylindrical Cavity Expansion ◽  
Plastic Materials ◽  
Long Rod ◽  
Expansion Model ◽  
Elastic Plastic Materials ◽  
The Impact

A finite cylindrical cavity expansion model for metallic thick targets with finite planar sizes, composed of ideal elastic-plastic materials, with penetration of high-speed long rod is presented by using the unified strength theory. Considering the lateral boundary and mass abrasion of the target, the penetration resistance and depth formulas are proposed, solutions of which are obtained by MATLAB program. Then, a series of different criteria-based analytical solutions are obtained and the ranges of penetration depth of targets with different ratios of target radius to projectile radius (rt/rd) are predicted. Meanwhile, the numerical simulation is performed using the ANSYS/LS-DYNA finite element code to investigate the variations in residual projectile velocity, length, and mass abrasion. It shows that various parameters have influences on the antipenetration performance of the target, such as the strength coefficient b, rt/rd, the shape of the projectile nose, and the impact velocity of the projectile, among which the penetration depth has increased by 18.95% as b = 1 decreases to b = 0 and has increased by 32.28% as rt/rd = 19.88 decreases to rt/rd = 4.9.

The Propagation of Plasticity in Uniaxial Compression

1948 ◽  
Vol 15 (3) ◽  
pp. 256-260 ◽  
Author(s):  
M. P. White ◽  
LeVan Griffis
Keyword(s):  
Uniaxial Compression ◽  
Thin Sheet ◽  
High Stress ◽  
Stress And Strain ◽  
Velocity Range ◽  
Plastic Materials ◽  
The Face ◽  
Elastic Plastic Materials ◽  
The Impact ◽  
Type Of Behavior

Abstract A theoretical investigation of the mechanism of uniaxial compression impact on elastic-plastic materials is described in this paper. The method of analysis is similar in some respects to that previously given for tension impact on such materials. It is concluded that four different kinds of behavior can occur, depending upon the impact velocity. In the lowest velocity range the behavior in compression is similar to that found in tension. In this case stress and strain are propagated from the point of impact as a zone or wave front of ever-increasing length. This type of behavior ends at a velocity corresponding to the “critical” velocity found in tension impact. Within the next higher velocity range, stress and strain are propagated as a shock-type wave, or wave of very small length in which the transition from low to high stress and strain is very abrupt. At still higher impact velocities, there occurs “flowing deformation” in which the material is too weak to maintain coherency. Here there is a steady flow of the material toward and against the hammer, after which it flows in a thin sheet radially outward over the face of the hammer. The final possible state occurs at impact velocities greater than the speed of an elastic wave, so that no disturbance can escape from the hammer into the medium. Here the behavior is essentially that of a fluid, impact force being independent of strength of material.

High-speed impacts of slender bodies into non-smooth, complex fluids

2018 ◽  
Vol 861 ◽  
Author(s):  
Ishan Sharma
Keyword(s):  
Penetration Depth ◽  
High Speed ◽  
Complex Fluids ◽  
Laboratory Data ◽  
Impact Speed ◽  
High Speed Impact ◽  
Smooth Complex ◽  
Theoretical Predictions ◽  
Slender Bodies ◽  
The Impact

We present a simple hydrodynamical model for the high-speed impact of slender bodies into frictional geomaterials such as soils and clays. We model these materials as non-smooth, complex fluids. Our model predicts the evolution of the impactor’s speed and the final penetration depth given the initial impact speed, and the material and geometric parameters of the impactor and the impacted material. As an application, we investigate the impact of deep-penetrating anchors into seabeds. Our theoretical predictions are found to match field and laboratory data very well.

Evaluation of the Impact Formulae for Rigid Projectile Striking on Concrete Target

2011 ◽  
Vol 368-373 ◽  
pp. 894-900 ◽  
Author(s):  
Hao Wu ◽  
Qin Fang
Keyword(s):  
Penetration Depth ◽  
Empirical Formula ◽  
High Strength Concrete ◽  
High Speed ◽  
High Strength ◽  
Local Damage ◽  
High Speed Impact ◽  
Rigid Projectile ◽  
Semi Empirical ◽  
The Impact

Based on the large amounts of field impact tests with different projectile nosed shapes, the abilities of the existing classical empirical and semi-empirical impact formulae in predicting the local damage of normal and high strength concrete targets (NSCT & HSCT) under the strike of rigid projectile were evaluated. It finds that, firstly, for the penetration depth, the Forrestal and Chen & Li semi-empirical formulae, BRL and Whiffen empirical formulae are advised for the NSCT under the impact of ogive nosed projectile; and Chen & Li semi-empirical formula and ACE empirical formulae are advised for the NSCT under the impact of special nosed projectile; the dimensionless penetration depth of NSCT increases linearly with the non-dimensional impact factor. Secondly, for the penetration depth, Chen & Li semi-empirical formula is advised for the HSCT under the mid-to-high speed impact, and the existing formulae are not applicable while the speed of the projectile was relatively low. Thirdly, for the perforation mode of the target, the BRL and Chang empirical formulae are advised for the NSCT, and the Chen semi-empirical formula, ACE and BRL empirical formulae are advised for the HSCT.

Cohesive Release Loads in a General Finite Element Model of a Propagating Crack

2009 ◽  
Vol 417-418 ◽  
pp. 517-520 ◽  
Author(s):  
A. Fontana ◽  
M. Minotti ◽  
Pietro Salvini
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Crack Tip ◽  
Reference Value ◽  
Element Model ◽  
Cohesive Model ◽  
Plastic Materials ◽  
T Stress ◽  
Speed Mode ◽  
Elastic Plastic Materials

High speed MODE I crack growth in elastic-plastic materials, involving large scale plasticity and dynamic effects connected to rapid propagation, is faced through a cohesive model to tune force nodal release. The stress resisting to the opening of the edges in the cohesive zone should account of effective stress field ahead crack tip. In this paper a reference value is accounted: it represents the maximum closing stress measured at the crack tip, where the cohesive effects begin. A bi-parametric analytical formulation of stress distribution ahead the crack tip is suggested. The bi-parametric formulation is able to extrapolate the stress at the tip whatever is the T-stress (i.e. the stress acting in the direction of fracture propagation), thus completely defining the cohesive loads.

A response to—“Comment on the evaluation of the constant β relating the contact stiffness to the contact area in nanoindentation for sphero-conical indenters:” Comment to paper “Penetration depth and tip radius dependence on the correction factor in nanoindentation measurements” by J.M. Meza et al. [J. Mater. Res. 23(3), 725 (2008)]

2012 ◽  
Vol 27 (8) ◽  
pp. 1208-1210
Author(s):  
Juan Manuel Meza ◽  
Fazilay Abbes ◽  
Jaime Alexis Garcia Guzman ◽  
Michel Troyon
Keyword(s):  
Penetration Depth ◽  
Correction Factor ◽  
Contact Area ◽  
Contact Stiffness ◽  
Depth Range ◽  
Dimensionless Analysis ◽  
Plastic Materials ◽  
Variation Range ◽  
Elastic Plastic Materials ◽  
Tip Radius

The signification of the correction factor β that we defined for elastic material [J.M. Meza et al. J. Mater. Res.23(3), 725, (2008)] does not correspond to that of factor β in the Sneddon relationship between unloading contact stiffness, elastic modulus, and contact area as remarked by Durst et al. in their Comment (doi:10.1557/jmr.2012.41). To complete the results of Durst et al., the calculation of β is extended to a larger penetration depth range. It is shown that β depends on the depth to tip radius ratio, h/R, and on the Poisson’s ratio according to dimensionless analysis. The variation range of β is about 1.02–1.09 for 0.3 < h/R < 3 for purely elastic materials but can be much larger in case of elastic–plastic materials as shown [F. Abbes et al. J. Micromech. Microeng.20, 65003 (2010)].

Anti-Penetration Performance of Ceramic Composite Armor Analysis Based on the Unified Strength Theory

2012 ◽  
Vol 557-559 ◽  
pp. 353-356
Author(s):  
Bao Feng Li ◽  
Jian Zheng ◽  
Xin Hua Ni ◽  
Yan Mei Qu ◽  
Xiao Wen Li ◽  
...  
Keyword(s):  
Compression Ratio ◽  
Ceramic Composite ◽  
Strength Theory ◽  
Experiment Data ◽  
Unified Strength Theory ◽  
Composite Armor ◽  
Long Rod ◽  
Ceramic Composite Armor ◽  
Dynamics Problems ◽  
Ceramic Targets

The resistance pressure was the key to solve these problems that long rod projectiles penetrated ceramic targets at high velocity. Based on the twin shear united strength theory and the A-T model, the penetration depth were calculated. But the calculation result didn’t agree with experiment data. So the tension-compression ratio was redefined to apply to the dynamics problems according to the experiment data. And satisfied results were obtained.

Finite Cylindrical Cavity Expansion Model for Penetration of Steel-Tube-Confined Concrete Targets

2014 ◽  
Vol 1065-1069 ◽  
pp. 1065-1068
Author(s):  
Yang Yue Ye Cao ◽  
Zhi Gang Jiang ◽  
Qing Hua Tan
Keyword(s):  
Cylindrical Cavity ◽  
Steel Tube ◽  
Confined Concrete ◽  
Cavity Expansion ◽  
Strength Theory ◽  
Expansion Process ◽  
Cylindrical Cavity Expansion ◽  
Expansion Model ◽  
Better Than ◽  
Good Agreement

Concrete is a brittle material which cracks under the tension and pulverized when the compressive stress exceeds the ultimate compressive strength. Confined concrete performs better than that of concrete without confinement in resisting penetration. Based on the Griffith strength theory, a quasi-static cylindrical cavity expansion model for the penetration of steel-tube-confined concrete targets is proposed. Numerical results show that ratio of tube wall thickness to tube radius significantly effects cavity expansion stress, which is in proportion to the former ratio. The results are in good agreement with the cavity expansion process.

A Dynamic Cylindrical Cavity Expansion Model for the Penetration of Confined Concrete Targets

2013 ◽  
Vol 341-342 ◽  
pp. 467-471 ◽  
Author(s):  
Ming Zhen ◽  
Zhi Gang Jiang ◽  
Dian Yi Song
Keyword(s):  
Cylindrical Cavity ◽  
Numerical Results ◽  
Confined Concrete ◽  
Cavity Expansion ◽  
Strength Theory ◽  
Normal Concrete ◽  
Cylindrical Cavity Expansion ◽  
Concrete Materials ◽  
Expansion Model ◽  
Better Than

The anti-projectile performance of the confined concrete is better than that of the normal concrete. When the radius of the confining tube is relatively small, the confined concrete would be in comminuted stage during the penetrating process of projectiles. Based on the assumption that comminuted concrete materials obey Griffith strength theory, a finite cylindrical cavity expansion model for confined concrete targets is proposed. Numerical results show that the lateral confinement affects little on the cavity stress for relatively small confining rigidity, and the cavity stress increases significantly with the increase of the radius ratio of cavity to confining tube for relatively large lateral confining rigidity.

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