Evaluation of High Strain Rate Characteristics of Metallic Sandwich Specimens

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Danish Iqbal ◽  
Vikrant Tiwari
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Volume Fraction ◽  
Split Hopkinson Pressure Bar ◽  
Three Dimensional ◽  
Wave Theory ◽  
Hopkinson Pressure Bar ◽  
Material Interfaces ◽  
Element Analysis ◽  
Pressure Bar

An attempt is made to investigate the dynamic compressive response of multilayered specimens in bilayered and trilayered configurations, using a split Hopkinson pressure bar (SHPB) and finite element analysis. Two constituent metals comprising the multilayered configurations were Al 6063-T6 and IS 1570. Multiple stack sequences of trilayered and bilayered configurations were evaluated at three different sets of strain rates, namely, 500, 800, and 1000 s−1. The experiments revealed that even with the same constituent volume fraction, a change in the stacking sequence alters the overall dynamic constitutive response. This change becomes more evident, especially in the plastic zone. The finite element analysis was performed using abaqus/explicit. A three-dimensional (3D) model of the SHPB apparatus used in the experiments was generated and meshed using the hexahedral brick elements. Dissimilar material interfaces were assigned different dynamic coefficients of friction. The fundamental elastic one-dimensional (1D) wave theory was then utilized to evaluate the stress–strain response from the nodal strain histories of the bars. Predictions from the finite element simulations along with the experimental results are also presented in this study. For most cases, finite element predictions match well with the experiments.

Punch shear performance and damage mechanisms of three-dimensional braided composite with different thicknesses

2018 ◽  
Vol 89 (11) ◽  
pp. 2126-2141
Author(s):  
Yuanyuan Li ◽  
Bohong Gu ◽  
Baozhong Sun ◽  
Zhijuan Pan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Modes ◽  
Split Hopkinson Pressure Bar ◽  
Three Dimensional ◽  
Damage Mechanism ◽  
Specimen Thickness ◽  
Analysis Model ◽  
Hopkinson Pressure Bar ◽  
Element Analysis

In this study, the punch shear properties and damage mechanism of three-dimensional braided carbon/epoxy composites with different thicknesses are investigated both experimentally and numerically. Three kinds of specimen thickness are prepared: 3 mm, 5 mm, and 8 mm. A modified split Hopkinson pressure bar with a specially designed punch shear fixture are used to conduct the punch shear tests. The results indicate that the punch shear modulus increases along with the specimen thickness, whereas the peak punch stress shows insensitivity to the change in thickness. The specific energy absorption decreases with an increase in thickness due to a reduction in composite damage. Moreover, the dominant failure modes under punch shear loadings are discussed through SEM examinations and finite element analysis. The results show a high level of agreement between the experimental and finite element analysis models. Particularly, the finite element analysis model simulates the punch shear damage evolution at various high strain rates. Both the stress distribution and stress propagation process are also investigated in the model. It is found that a low-stress zone appeared in the punch region and the zone area decreases as the thickness increases.

Confinement device to assess dynamic crushability of wood material

2017 ◽  
Vol 232 (8) ◽  
pp. 1418-1432 ◽  
Author(s):  
J Wouts ◽  
G Haugou ◽  
M Oudjene ◽  
H Naceur ◽  
D Coutellier
Keyword(s):  
Finite Element ◽  
Split Hopkinson Pressure Bar ◽  
Large Diameter ◽  
Hybrid Approach ◽  
Hopkinson Pressure Bar ◽  
Wood Material ◽  
Element Analysis ◽  
Multiaxial Stress State ◽  
Split Hopkinson ◽  
Pressure Bar

Cellular materials such as wood are widely and advantageously used as shock absorbers in various transport applications. The design and manufacturing of structures made of these materials require the knowledge of their dynamic compressive properties at various strain rates and stress states. Therefore, it is challenging to conduct dynamic multiaxial stress state experiments and especially on split-Hopkinson pressure bar apparatus where stress hardening increases as a function of velocity. This paper presents the so-called verification and validation methodology for confining solutions dedicated to impact on viscoelastic split-Hopkinson pressure bar system with large diameter bars. The method is a hybrid approach combining finite element analysis and an original experimental validation. Based on finite element results, particular attention is given to the mass, the material and the geometry to minimize the confining device influence on the propagation of elastic waves and thus on the material response of the tested specimens. It is essential to avoid spurious reflected waves at the new interfaces of the system in order to ensure the validity of the experimentation. The numerically predicted solutions are experimentally validated and preliminary results in the context of dynamic loadings using wood material are presented.

Preliminary Finite Element Analysis of Shot Peening for Austenitic Stainless Steels

2010 ◽  
Vol 452-453 ◽  
pp. 813-816
Author(s):  
Teruaki Yamada ◽  
Masatoshi Kuroda ◽  
Kazuya Mori
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steels ◽  
Shot Peening ◽  
Split Hopkinson Pressure Bar ◽  
Austenitic Stainless Steels ◽  
High Rate ◽  
Hopkinson Pressure Bar ◽  
Element Analysis

In this study, the preliminary finite element analysis of shot peening was carried out in order to investigate the fundamental mechanism of shot peening for stainless steels. For numerical simulations with high-rate deformation such as shot peening, rate-dependence plasticity models are necessary to get better analysis results. Therefore the stress-strain relation at high-strain rates of austenitic stainless steels were obtained by split Hopkinson pressure bar (SHPB) tests. The parameters of Johnson-Cook plasticity model were determined from the result, and then the finite element analysis of shot peening was carried out using the parameters. Consequently, the compressive residual stress was created beneath the surface of the target but was changed to the tensile residual stress with an increase in the depth.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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