scholarly journals Integrated Experimental, Atomistic, and Microstructurally Based Finite Element Investigation of the Dynamic Compressive Behavior of 2139 Aluminum

2009 ◽  
Vol 76 (5) ◽  
Author(s):  
K. Elkhodary ◽  
Lipeng Sun ◽  
Douglas L. Irving ◽  
Donald W. Brenner ◽  
G. Ravichandran ◽  
...  
Keyword(s):  
Finite Element ◽  
Density Functional ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
Density Functional Theory Calculations ◽  
Element Model ◽  
Hopkinson Pressure Bar ◽  
Element Analysis ◽  
Spatial And Temporal Scales ◽  
Orientation Relations

The objective of this study was to identify the microstructural mechanisms related to the high strength and ductile behavior of 2139-Al, and how dynamic conditions would affect the overall behavior of this alloy. Three interrelated approaches, which span a spectrum of spatial and temporal scales, were used: (i) The mechanical response was obtained using the split Hopkinson pressure bar, for strain-rates ranging from 1.0×10−3 s to 1.0×104 s−1. (ii) First principles density functional theory calculations were undertaken to characterize the structure of the interface and to better understand the role played by Ag in promoting the formation of the Ω phase for several Ω-Al interface structures. (iii) A specialized microstructurally based finite element analysis and a dislocation-density based multiple-slip formulation that accounts for an explicit crystallographic and morphological representation of Ω and θ′ precipitates and their rational orientation relations were conducted. The predictions from the microstructural finite element model indicated that the precipitates continue to harden and also act as physical barriers that impede the matrix from forming large connected zones of intense plastic strain. As the microstructural FE predictions indicated, and consistent with the experimental observations, the combined effects of θ′ and Ω, acting on different crystallographic orientations, enhance the strength and ductility, and reduce the susceptibility of 2139-Al to shear strain localization due to dynamic compressive loads.

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.

A Study of the Dynamic Behavior of Elastomeric Materials Using Finite Elements

1996 ◽  
Vol 118 (4) ◽  
pp. 503-508 ◽  
Author(s):  
G. E. Vallee ◽  
Arun Shukla
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Split Hopkinson Pressure Bar ◽  
Material Model ◽  
Element Model ◽  
Material Behavior ◽  
Hopkinson Pressure Bar ◽  
Material Models ◽  
Finite Element Program ◽  
Elastomeric Materials

A numerical method is described for determining a dynamic finite element material model for elastomeric materials loaded primarily in compression. The method employs data obtained using the Split Hopkinson Pressure Bar (SHPB) technique to define a molecular constitutive model for elastomers. The molecular theory is then used to predict dynamic material behavior in several additional deformation modes used by the ABAQUS/Explicit (Hibbitt, Karlsson, and Sorenson, 1993a) commercial finite element program to define hyperelastic material behavior. The resulting dynamic material models are used to create a finite element model of the SHPB system, yielding insights into both the accuracy of the material models and the SHPB technique itself when used to determine the dynamic behavior of elastomeric materials. Impact loading of larger elastomeric specimens whose size prohibits examination by the SHPB technique are examined and compared to the results of dynamic load-deflection experiments to further verify the dynamic material models.

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.

scholarly journals Mechanical and thermo-mechanical response of a lead-core bearing device subjected to different loading conditions

2018 ◽  
Vol 165 ◽  
pp. 16011
Author(s):  
Todor Zhelyazov ◽  
Rajesh Rupakhety ◽  
Simon Olafsson
Keyword(s):  
Finite Element ◽  
Seismic Isolation ◽  
Mechanical Response ◽  
Constitutive Relations ◽  
Element Model ◽  
General Purpose ◽  
Constitutive Laws ◽  
Macroscopic Model ◽  
Loading Conditions ◽  
Element Analysis

The contribution is focused on the numerical modelling, simulation and analysis of a lead-core bearing device for passive seismic isolation. An accurate finite element model of a lead-core bearing device is presented. The model is designed to analyse both mechanical and thermo-mechanical responses of the seismic isolator to different loading conditions. Specifically, the mechanical behaviour in a typical identification test is simulated. The response of the lead-core bearing device to circular sinusoidal paths is analysed. The obtained shear displacement – shear force relationship is compared to experimental data found in literature sources. The hypothesis that heating of the lead-core during cyclic loading affects the degrading phenomena in the bearing device is taken into account. Constitutive laws are defined for each material: lead, rubber and steel. Both predefined constitutive laws (in the used general–purpose finite element code) and semi-analytical procedures aimed at a more accurate modelling of the constitutive relations are tested. The results obtained by finite element analysis are to be further used to calibrate a macroscopic model of the lead-core bearing device seen as a single-degree-of-freedom mechanical system.

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.

Differences of transverse impact damages in 3D angle-interlock woven composites between warp and weft directions

2019 ◽  
Vol 28 (8) ◽  
pp. 1203-1227 ◽  
Author(s):  
Chunlei Ren ◽  
Amna Siddique ◽  
Baozhong Sun ◽  
Bohong Gu
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Kink Band ◽  
Woven Composites ◽  
Hopkinson Pressure Bar ◽  
Transverse Impact ◽  
Element Analysis ◽  
The Impact ◽  
Impact Damages

Transverse impact damages of 3D angle-interlock woven composites have been tested at split Hopkinson pressure bar along warp and weft directions respectively. The impact deformation and damages were photographed with a high-speed camera. A finite element analyses model was established at mesostructure level to unveil the inner yarn, resin damages, and stress distributions. There are significant differences of yarn breakages and interface damage between the two directions. From finite element analysis simulations and scanning electron microscope photographs, we found the warp yarns were in kink band deformation and shear damage, while the weft yarns were in compressive failure and had smooth fractography. The warp yarns which run through-thickness directions impede transverse impact crack propagations in resins and lead to high delamination resistances. The straight weft yarns impart high stiffness and strength to in-plane directions.

Experimental and numerical analysis of stress wave propagation in polymers and the role of interfaces in armour systems

2012 ◽  
Vol 2 (4) ◽  
Author(s):  
Chandragupt Gorwade ◽  
Ian Ashcroft ◽  
Vadim Silberschmidt ◽  
Foz Hughes ◽  
Gerry Swallowe
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Split Hopkinson Pressure Bar ◽  
Polymeric Materials ◽  
Element Model ◽  
Stress Wave Propagation ◽  
Hopkinson Pressure Bar ◽  
Impedance Mismatch ◽  
Stress And Deformation

AbstractAdvanced polymeric materials are finding an increasing range of industrial and defence applications. These materials have the potential to improve combat survivability, whilst reducing the cost and weight of armour systems. In this paper the results from a split Hopkinson pressure bar (SHPB) test of a high density polyethylene (HDPE) sample involving multiple stress waves is discussed with aid of a finite element model of the test. It is seen that the phenomenon of impedance mismatch at interfaces plays an important role in the levels of stress and deformation seen in the sample. A multi-layer armour system is then investigated using the finite element model. This case study illustrates the role of impedance mismatch and interface engineering in the design and optimisation of armour solutions.

Finite Element Analysis of Deep Transverse Metatarsal Ligaments Mechanical Response during Landing

2012 ◽  
Vol 472-475 ◽  
pp. 2558-2561 ◽  
Author(s):  
Y.D. Gu ◽  
M Rong ◽  
Z.Y Li ◽  
M.J Lake ◽  
G.Q Ruan
Keyword(s):  
Finite Element ◽  
Load Transfer ◽  
Mechanical Response ◽  
Material Model ◽  
Element Model ◽  
Measurement Technology ◽  
Element Analysis ◽  
Load Transfer Mechanism ◽  
Metatarsal Bones ◽  
Transverse Arch

The deep transverse metatarsal ligaments (DTML) play an important role in stabilizing the metatarsal bones and manipulating foot transverse arch deformation. However, the biomechanical research about DTML in the foot maneuver is quite few. Due to the difficulties and lack of better measurement technology for these ligaments experimental monitor, the load transfer mechanism and internal stress state also hadn’t been well addressed. The purpose of this study was to develop a detailing foot finite element model including DTML tissues, to investigate the mechanical response of DTML during the landing condition. The DTML was considered as hyperelastic material model was used to represent the nonlinear and nearly incompressible nature of the ligament tissue. From the simulation results, it is clearly to find that the peak maiximal principal stress of DTML was between the third and fourth metatarsals. Meanwhile, it seems the DTML in the middle position experienced higher tension than the sides DTML.

A Three-dimensional Finite Element Model for Arterial Clamping

2002 ◽  
Vol 124 (4) ◽  
pp. 355-363 ◽  
Author(s):  
Thomas C. Gasser ◽  
Christian A. J. Schulze-Bauer ◽  
Gerhard A. Holzapfel
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Axial Tensile ◽  
Injury Mechanisms ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Clamp induced injuries of the arterial wall may determine the outcome of surgical procedures. Thus, it is important to investigate the underlying mechanical effects. We present a three-dimensional finite element model, which allows the study of the mechanical response of an artery–treated as a two-layer tube-during arterial clamping. The important residual stresses, which are associated with the load-free configuration of the artery, are also considered. In particular, the finite element analysis of the deformation process of a clamped artery and the associated stress distribution is presented. Within the clamping area a zone of axial tensile peak-stresses was identified, which (may) cause intimal and medial injury. This is an additional injury mechanism, which clearly differs from the commonly assumed wall damage occurring due to compression between the jaws of the clamp. The proposed numerical model provides essential insights into the mechanics of the clamping procedure and the associated injury mechanisms. It allows detailed parameter studies on a virtual clamped artery, which can not be performed with other methodologies. This approach has the potential to identify the most appropriate clamps for certain types of arteries and to guide optimal clamp design.

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.

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