On the influence of fracture criterion in projectile impact of steel plates

The present study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of a lap bolted joint used in the suspension parts of a car body. For the accurate prediction of crash characteristics of car bodies by computer-aided engineering (CAE), it is also necessary to examine the behaviour and fracture of the jointed steel plates subjected to impact loads. Although the actual impact fracture of jointed steel plates of a lap bolted joint in cars is complicated, for simplifying it is classified into the shear fracture and the extractive fracture of jointed steel plates. Three kinds of steel plates, i.e., common steel with the tensile strength of 270 MPa and two high tensile strength steels with the tensile strength of 440 and 590 MPa level used for vehicles, are examined. In the impact shear test, the specimens are made of two plates and jointed by a bolt, and in the impact extractive test the specimens are made of a plate and drilled in the centre for a bolt. The impact shear test of jointed steel plates of lap bolted joints is performed using a modified split Hopkinson bar apparatus, while the impact extractive one is performed using one-bar method. Numerical simulations by a FEM code LS-DYNA are also carried out in order to understand the mechanism of shearing and extractive fractures process of jointed steel plates. The obtained results suggest that a stress-based fracture criterion may be developed for the impact shearing and extractive fractures of jointed steel plates of lap bolted joints used in a car body.

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Experimental and Numerical Study on the Protective Behavior of Weldox 900 E Steel Plates Impacted by Blunt-Nosed Projectiles

Metals ◽

10.3390/met12010141 ◽

2022 ◽

Vol 12 (1) ◽

pp. 141

Author(s):

Yahui Shi ◽

Ang Hu ◽

Taisheng Du ◽

Xinke Xiao ◽

Bin Jia

Keyword(s):

Numerical Simulation ◽

Finite Element ◽

Fracture Criterion ◽

Numerical Study ◽

Mesh Size ◽

High Strength ◽

Element Model ◽

Steel Plates ◽

Protective Behavior ◽

The Finite Element Model

To demonstrate the importance of incorporating Lode angle into fracture criterion in predicting the penetration resistance of high-strength steel plates, ballistic tests of blunt-nosed projectiles with a diameter of 5.95 mm impacted 4 mm thick Weldox 900 E steel plates were conducted. Impacting velocity range was 136.63~381.42 m/s. The fracture behavior and the ballistic limit velocities (BLVs) were obtained by fitting the initial-residual velocities of the projectiles. Subsequently, axisymmetric finite element (FE) models parallel to the tests were built by using Abaqus/Explicit software, and the Lode-independent Johnson–Cook (JC) and the Lode-dependent ASCE fracture criterion were incorporated into the finite element model for numerical simulation. Meanwhile, to verify the sensitivity of the mesh size in the numerical simulation, different mesh sizes were used in the shear plug area of the target. It can be found that Weldox 900 E steel has obvious mesh size sensitivity by comparing the experimental results and numerical simulation, and the JC fracture criterion and the ASCE fracture criterion predicted similar BLV for the same mesh size.

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On the influence of constitutive relation in projectile impact of steel plates

International Journal of Impact Engineering ◽

10.1016/j.ijimpeng.2005.10.003 ◽

2007 ◽

Vol 34 (3) ◽

pp. 464-486 ◽

Cited By ~ 81

Author(s):

S. Dey ◽

T. Børvik ◽

O.S. Hopperstad ◽

M. Langseth

Keyword(s):

Constitutive Relation ◽

Steel Plates ◽

Projectile Impact

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On the Influence of Fracture Criterion on Perforation of High-Strength Steel Plates Subjected to Armour Piercing Projectile

Archive of Mechanical Engineering ◽

10.1515/meceng-2015-0010 ◽

2015 ◽

Vol 62 (2) ◽

pp. 157-179 ◽

Cited By ~ 3

Author(s):

Djalel Eddine Tria ◽

Radosław Trebinski

Keyword(s):

Shear Stress ◽

Fracture Criterion ◽

Maximum Shear Stress ◽

Equivalent Plastic Strain ◽

Stress Triaxiality ◽

High Strength ◽

Steel Plates ◽

Fracture Model ◽

Simple Material ◽

Shear Plugging

Abstract This paper presents a numerical investigation of fracture criterion influence on perforation of high-strength 30PM steel plates subjected to 7.62x51 mm Armour Piercing (AP) projectile. An evaluation of four ductile fracture models is performed to identify the most suitable fracture criterion. Included in the paper is the Modified Johnson-Cook (MJC) constitutive model coupled separately with one of these fracture criteria: the MJC fracture model, the Cockcroft-Latham (CL), the maximum shear stress and the constant failure strain models. A 3D explicit Lagrangian algorithm that includes both elements and particles, is used in this study to automatically convert distorted elements into meshless particles during the course of the computation. Numerical simulations are examined by comparing with the experimental results. The MJC fracture model formulated in the space of the stress triaxiality and the equivalent plastic strain to fracture were found capable of predicting the realistic fracture patterns and at the same time the correct projectile residual velocities. However, this study has shown that CL one parameter fracture criterion where only one simple material test is required for calibration is found to give good results as the MJC failure criterion. The maximum shear stress fracture criterion fails to capture the shear plugging failure and material fracture properties cannot be fully characterized with the constant fracture strain

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Calculation And Experimental Substantiation Of Optimal Design Of The Welded Joint Of Plates On Соver Plates

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2020.03.17-24 ◽

2020 ◽

pp. 17-24

Keyword(s):

Welded Joint ◽

Experimental Studies ◽

Engineering Calculation ◽

Tensile Tests ◽

Physical Nonlinearity ◽

Steel Plates ◽

Optimal Parameters ◽

Actual Problem ◽

Numerical Research ◽

Cover Plates

The article is devoted to the actual problem of assigning optimal parameters for connecting steel plates on cover plates with angular welds that are widely used in construction practice. The article presents the results of a comprehensive study of operation of a welded assembly of the plates connection on cover plates. An algorithm is proposed for determining the optimal parameters of a welded joint with fillet welds on the cover plates, which makes it possible to obtain a strength balanced connection. The results of full-scale tensile tests of models were presented. These results confirmed the correctness of the assumed design assumptions, and made it possible to obtain a form of destruction, not characteristic and not described in the normative literature, expressed by cutting the main elements along the length of the overlap in the joint. The possibility of such a form of destruction was confirmed by the results of numerical research in a nonlinear formulation. The optimal parameters of the nodal welded joint determined by engineering calculation are confirmed by experimental studies, as well as by the results of numerical experiments on models of calculation schemes, taking into account the physical nonlinearity of the material operation. The obtained dependence for determining the bearing capacity of the joint by the cut-off mechanism and the expression for limiting the overlap length of the cover plates will make it possible to predict the nature of the fracture and design equally strong joints.

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