A Coarse Model for the Multiaxial Elastic-Plastic Response of Ductile Porous Materials

2019 ◽  
Vol 86 (8) ◽  
Author(s):  
Andreas Schiffer ◽  
Panagiotis Zacharopoulos ◽  
Dennis Foo ◽  
Vito L. Tagarielli
Keyword(s):  
Mechanical Response ◽  
Hydrostatic Stress ◽  
Parent Material ◽  
Porous Solids ◽  
Plastic Response ◽  
Elastic Plastic ◽  
Numerical Studies ◽  
Coarse Model ◽  
Modeling Strategy ◽  
Good Agreement

We propose a modeling strategy to predict the mechanical response of porous solids to imposed multiaxial strain histories. A coarse representation of the microstructure of a porous material is obtained by subdividing a volume element into cubic cells by a regular tessellation; some of these cells are modeled as a plastically incompressible elastic-plastic solid, representing the parent material, while the remaining cells, representing the pores, are treated as a weak and soft compressible solid displaying densification behavior at large compressive strains. The evolution of homogenized deviatoric and hydrostatic stress is explored for different porosities by finite element simulations. The predictions are found in good agreement with previously published numerical studies in which the microstructural geometry was explicitly modeled.

scholarly journals The Elastic-Plastic Response of Thin Spherical Shells to Internal Blast Loading

1960 ◽  
Vol 27 (1) ◽  
pp. 139-144 ◽  
Author(s):  
W. E. Baker
Keyword(s):  
Numerical Solutions ◽  
Equations Of Motion ◽  
Analytic Solutions ◽  
Plastic Response ◽  
Transient Pressure ◽  
Elastic Plastic ◽  
Small Deflection ◽  
Thin Spherical Shell ◽  
Internal Blast Loading ◽  
Good Agreement

In this paper, the theory is developed for the elastic-plastic response of a thin spherical shell to spherically symmetric internal transient pressure loading. Analytic solutions are obtained to the linear, small-deflection equations of motion for shell materials which exhibit various degrees of strain-hardening. Numerical solutions obtained by digital computer are also presented for the equations for large deflections obtained by accounting for shell thinning and increase in radius during deformation. The theory is compared with experiment, and is shown to be in good agreement.

Elastic-Plastic Response of 6061-T6 Aluminum Beams to Impulse Loads

1976 ◽  
Vol 43 (2) ◽  
pp. 259-262 ◽  
Author(s):  
M. J. Forrestal ◽  
D. L. Wesenberg
Keyword(s):  
Sine Wave ◽  
Approximate Theory ◽  
Strain Gages ◽  
Plastic Response ◽  
Peak Displacement ◽  
Elastic Plastic ◽  
Numerical Predictions ◽  
Time Histories ◽  
Measured Displacement ◽  
Good Agreement

The elastic-plastic response of 6061-T6 aluminum beams is examined experimentally and analytically. Simply supported beams are loaded with half-sine wave, short-duration magnetic pressure pulses and the response is monitored with a framing camera and strain gages. A closed-form elastic-plastic approximate theory for peak displacement is derived and compared with measurements and a numerical analysis. Measured displacement-time and strain-time histories are also compared with numerical predictions. Good agreement is shown between measurements and predictions.

scholarly journals Visco-Hyperelastic Characterization of the Equine Immature Zona Pellucida

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1223
Author(s):  
Elisa Ficarella ◽  
Mohammad Minooei ◽  
Lorenzo Santoro ◽  
Elisabetta Toma ◽  
Bartolomeo Trentadue ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Soft Matter ◽  
Mechanical Response ◽  
Mechanical Characterization ◽  
Nonlinear Material ◽  
Prony Series ◽  
Critical Comparison ◽  
Highly Nonlinear ◽  
Good Agreement

This article presents a very detailed study on the mechanical characterization of a highly nonlinear material, the immature equine zona pellucida (ZP) membrane. The ZP is modeled as a visco-hyperelastic soft matter. The Arruda–Boyce constitutive equation and the two-term Prony series are identified as the most suitable models for describing the hyperelastic and viscous components, respectively, of the ZP’s mechanical response. Material properties are identified via inverse analysis based on nonlinear optimization which fits nanoindentation curves recorded at different rates. The suitability of the proposed approach is fully demonstrated by the very good agreement between AFM data and numerically reconstructed force–indentation curves. A critical comparison of mechanical behavior of two immature ZP membranes (i.e., equine and porcine ZPs) is also carried out considering the information on the structure of these materials available from electron microscopy investigations documented in the literature.

Modelling the nano indentation behaviour of recast layer and heat affected zone on reverse micro EDMed hemispherical feature

2021 ◽  
pp. 1-15
Author(s):  
Tribeni Roy ◽  
Anuj Sharma ◽  
Prabhat Ranjan ◽  
R. Balasubramaniam
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Heat Affected Zone ◽  
Parent Material ◽  
Recast Layer ◽  
Machined Surface ◽  
Nano Indentation ◽  
Fea Simulation ◽  
Load Displacement ◽  
Good Agreement

Abstract Electrical discharge machined surfaces inherently possess recast layer on the surface with heat affected zone (HAZ) beneath it and these have a detrimental effect on the mechanical properties viz. hardness, elastic modulus, etc. It is very difficult to experimentally characterise each machined surface. Therefore, an attempt is made in this study to numerically calculate the mechanical properties of the parent material, HAZ and the recast layer on a hemispherical protruded micro feature fabricated by reverse micro EDM (RMEDM). In the 1st stage, nano indentation was performed to experimentally determine the load-displacement plots, elastic modulus and hardness of the parent material, HAZ and the recast layer. In the 2nd stage, FEA simulation was carried out to mimic the nano indentation process and determine the load-displacement plots for all the three cases viz. parent material, recast layer and HAZ. Results demonstrated that the load'displacement plots obtained from numerical model in each case was in good agreement with that of the experimental curves. Based on simulated load-displacement plots, hardness was also calculated for parent material, HAZ and the recast layer. A maximum of 11% error was observed between simulated values of hardness and experimentally determined values.

Development and verification of a numerical model for the analysis of geosynthetic-reinforced soil segmental walls under working stress conditions

2005 ◽  
Vol 42 (4) ◽  
pp. 1066-1085 ◽  
Author(s):  
Kianoosh Hatami ◽  
Richard J Bathurst
Keyword(s):  
Numerical Model ◽  
Constitutive Models ◽  
Reinforced Soil ◽  
Stress Conditions ◽  
Soil Reinforcement ◽  
Lagrangian Analysis ◽  
Elastic Plastic ◽  
Geosynthetic Reinforced Soil ◽  
Working Stress ◽  
Good Agreement

The paper describes a numerical model that was developed to simulate the response of three instrumented, full-scale, geosynthetic-reinforced soil walls under working stress conditions. The walls were constructed with a fascia column of solid modular concrete units and clean, uniform sand backfill on a rigid foundation. The soil reinforcement comprised different arrangements of a weak biaxial polypropylene geogrid reinforcement material. The properties of backfill material, the method of construction, the wall geometry, and the boundary conditions were otherwise nominally the same for each structure. The performance of the test walls up to the end of construction was simulated with the finite-difference-based Fast Lagrangian Analysis of Continua (FLAC) program. The paper describes FLAC program implementation, material properties, constitutive models for component materials, and predicted results for the model walls. The results predicted with the use of nonlinear elastic-plastic models for the backfill soil and reinforcement layers are shown to be in good agreement with measured toe boundary forces, vertical foundation pressures, facing displacements, connection loads, and reinforcement strains. Numerical results using a linear elastic-plastic model for the soil also gave good agreement with measured wall displacements and boundary toe forces but gave a poorer prediction of the distribution of strain in the reinforcement layers.Key words: numerical modelling, retaining walls, reinforced soil, geosynthetics, FLAC.

Elastoplastic Analysis of Layered Metal Matrix Composite Cylinders—Part I: Theory

1996 ◽  
Vol 118 (1) ◽  
pp. 13-20 ◽  
Author(s):  
R. S. Salzar ◽  
M.-J. Pindera ◽  
F. W. Barton
Keyword(s):  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Stiffness Matrix ◽  
Metal Matrix ◽  
Plastic Response ◽  
Solution Strategy ◽  
Composite Tubes ◽  
Elastic Plastic ◽  
Stiffness Matrices ◽  
Local Stiffness

An exact elastic-plastic analytical solution for an arbitrarily laminated metal matrix composite tube subjected to axisymmetric thermo-mechanical and torsional loading is presented. First, exact solutions for transversely isotropic and monoclinic (off-axis) elastoplastic cylindrical shells are developed which are then reformulated in terms of the interfacial displacements as the fundamental unknowns by constructing a local stiffness matrix for the shell. Assembly of the local stiffness matrices into a global stiffness matrix in a particular manner ensures satisfaction of interfacial traction and displacement continuity conditions, as well as the external boundary conditions. Due to the lack of a general macroscopic constitutive theory for the elastic-plastic response of unidirectional metal matrix composites, the micromechanics method of cells model is employed to calculate the effective elastic-plastic properties of the individual layers used in determining the elements of the local and thus global stiffness matrices. The resulting system of equations is then solved using Mendelson’s iterative method of successive elastic solutions developed for elastoplastic boundary-value problems. Part I of the paper outlines the aforementioned solution strategy. In Part II (Salzar et al., 1996) this solution strategy is first validated by comparison with available closed-form solutions as well as with results obtained using the finite-element approach. Subsequently, examples are presented that illustrate the utility of the developed solution methodology in predicting the elastic-plastic response of arbitrarily laminated metal matrix composite tubes. In particular, optimization of the response of composite tubes under internal pressure is considered through the use of functionally graded architectures.

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