scholarly journals Linear analysis of Atwood number effects on shear instability in the elastic–plastic solids

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xi Wang ◽  
Xiao-Mian Hu ◽  
Sheng-Tao Wang ◽  
Hao Pan ◽  
Jian-Wei Yin
Keyword(s):  
Dominant Role ◽  
Oblique Impact ◽  
Shear Instability ◽  
Unstable State ◽  
Interface Evolution ◽  
Plastic Properties ◽  
Motion Equations ◽  
Elastic Plastic ◽  
Continuity Equations ◽  
Atwood Number

AbstractThe evolution of shear instability between elastic–plastic solid and ideal fluid which is concerned in oblique impact is studied by developing an approximate linear theoretical model. With the velocities expressed by the velocity potentials from the incompressible and irrotational continuity equations and the pressures obtained by integrating momentum equations with arbitrary densities, the motion equations of the interface amplitude are deduced by considering the continuity of normal velocities and the force equilibrium with the perfectly elastic–plastic properties of solid at interface. The completely analytical formulas of the growth rate and the amplitude evolution are achieved by solving the motion equations. Consistent results are performed by the model and 2D Lagrange simulations. The characteristics of the amplitude development and Atwood number effects on the growth are discussed. The growth of the amplitude is suppressed by elastic–plastic properties of solids in purely elastic stage or after elastic–plastic transition, and the amplitude oscillates if the interface is stable. The system varies from stable to unstable state as Atwood number decreasing. For large Atwood number, elastic–plastic properties play a dominant role on the interface evolution which may influence the formation of the wavy morphology of the interface while metallic plates are suffering obliquely impact.

scholarly journals Finite Pure Plane Strain Bending of Inhomogeneous Anisotropic Sheets

Symmetry ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 145
Author(s):  
Sergei Alexandrov ◽  
Elena Lyamina ◽  
Yeong-Maw Hwang
Keyword(s):  
Plane Strain ◽  
Yield Criterion ◽  
Large Strains ◽  
Rigid Plastic ◽  
Plastic Properties ◽  
Elastic Plastic ◽  
Starting Point ◽  
The Difference ◽  
Inside Radius ◽  
Elastic Unloading

The present paper concerns the general solution for finite plane strain pure bending of incompressible, orthotropic sheets. In contrast to available solutions, the new solution is valid for inhomogeneous distributions of plastic properties. The solution is semi-analytic. A numerical treatment is only necessary for solving transcendent equations and evaluating ordinary integrals. The solution’s starting point is a transformation between Eulerian and Lagrangian coordinates that is valid for a wide class of constitutive equations. The symmetric distribution relative to the center line of the sheet is separately treated where it is advantageous. It is shown that this type of symmetry simplifies the solution. Hill’s quadratic yield criterion is adopted. Both elastic/plastic and rigid/plastic solutions are derived. Elastic unloading is also considered, and it is shown that reverse plastic yielding occurs at a relatively large inside radius. An illustrative example uses real experimental data. The distribution of plastic properties is symmetric in this example. It is shown that the difference between the elastic/plastic and rigid/plastic solutions is negligible, except at the very beginning of the process. However, the rigid/plastic solution is much simpler and, therefore, can be recommended for practical use at large strains, including calculating the residual stresses.

Determining Elastic-Plastic Properties of Al6061-T6 from Micro-Indentation Technique

2013 ◽  
Vol 592-593 ◽  
pp. 610-613
Author(s):  
Sina Amiri ◽  
Nora Lecis ◽  
Andrea Manes ◽  
Davide Mombelli ◽  
Marco Giglio
Keyword(s):  
Manufacturing Process ◽  
Optimization Procedure ◽  
Test System ◽  
Standard Test ◽  
Material Behavior ◽  
Plastic Properties ◽  
Representative Strain ◽  
Elastic Plastic ◽  
Dimensionless Analysis ◽  
Micro Indentation

Different approaches have been proposed in order to determine the material behavior of ductile materials. Since, the mechanical properties of a mechanical component are modified during manufacturing process due to plastic deformation, heat treatment and etc, a non-destructive indentation experimental procedure addressed to predict the elastic-plastic properties of material after manufacturing process is of interest. This is especially true for small size components where it is complex to extract specimens to test on standard test system. Based on dimensionless analysis and the concept of a representative strain, different approaches have been proposed to determine the material properties of power law materials by using indentation process. In this work, the Johnson-Cook (JC) constitutive model of the aluminum alloy Al6061-T6 is characterized by means of a well-defined optimization procedure based on micro-indentation testing and high fidelity finite element models and an optimization procedure but without the concept of dimensionless analysis and a representative strain. This methodology allows determining a set of JC constants for Al6061-T6. The obtained results have good agreement with parameters calibrated by means of universal standard tests and reverse engineering approach.

Evaluation of elastic, elastic-plastic properties of thin Pt wire by mechanical bending test

2010 ◽  
Vol 103 (2) ◽  
pp. 493-496 ◽  
Author(s):  
S. K. Deb Nath ◽  
Hironori Tohmyoh ◽  
M. A. Salam Akanda
Keyword(s):  
Bending Test ◽  
Plastic Properties ◽  
Elastic Plastic ◽  
Mechanical Bending

The influence of the Sc3+ dopant on the transmittance of (Y, Er)3Al5O12 ceramics

2021 ◽  
Author(s):  
Elena Dobretsova ◽  
Vadim Zhmykhov ◽  
Sergey Kuznetsov ◽  
Irina Chikulina ◽  
Marina Nikova ◽  
...  
Keyword(s):  
Optical Transmittance ◽  
Plastic Properties ◽  
Elastic Plastic

The substitution of Al3+ with the larger Sc3+ in the Er:YSAG structure leads to improved elastic–plastic properties. The optical transmittance of the ceramics is affected strongly by including Sc3+ and is increased to up to 60% at about 1.5 μm.

scholarly journals Gradient Elastic–Plastic Properties of Expanded Austenite Layer in 316L Stainless Steel

2018 ◽  
Vol 31 (8) ◽  
pp. 831-841 ◽  
Author(s):  
Yong Jiang ◽  
Yang Li ◽  
Yun-Fei Jia ◽  
Xian-Cheng Zhang ◽  
Jian-Ming Gong
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Plastic Properties ◽  
Elastic Plastic ◽  
Expanded Austenite

High Velocity Oblique Impact and Coefficient of Restitution for Head Disk Interface Operational Shock

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi ◽  
Robert M. Crone
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Damage ◽  
Element Model ◽  
Oblique Impact ◽  
Coefficient Of Restitution ◽  
Energy Losses ◽  
Elastic Plastic ◽  
Impact Angles ◽  
Operational Shock

With the increased use of hard disk drives (HDDs) in mobile and consumer applications combined with the requirement of higher areal density, there is enhanced focus on reducing head disk spacing, and consequently there is higher susceptibility of slider/disk impact damage during HDD operation. To investigate this impact process, a dynamic elastic-plastic finite element model of a sphere (representing a slider corner) obliquely impacting a thin-film disk was created to study the effect of the slider corner radius and the impact velocity on critical contact parameters. To characterize the energy losses due to the operational shock impact damage, the coefficient of restitution for oblique elastic-plastic impact was studied using the finite element model. A modification to an existing physics-based elastic-plastic oblique impact coefficient of restitution model was proposed to accurately predict the energy losses for a rigid sphere impacting a half-space. The analytical model results compared favorably to the finite element results for the range from low impact angles (primarily normal impacts) to high impact angles (primarily tangential impacts).

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