Plastic Behavior of Two-Layer Sandwich Structures

1973 ◽  
Vol 40 (1) ◽  
pp. 257-262 ◽  
Author(s):  
P. V. McLaughlin
Keyword(s):  
Shell Theory ◽  
Sandwich Structures ◽  
Fibrous Composite ◽  
Constitutive Relations ◽  
Sheet Material ◽  
Plastic Behavior ◽  
Thin Sheets ◽  
Elastic Plastic ◽  
Doubly Curved ◽  
Flow Laws

Sandwich structures composed of two thin sheets separated by a core which can support only transverse shear are both statically and kinematically determinate “in-plane”, allowing in-plane elastic-plastic behavior of such structures to be found in terms of sheet material properties. Unlike homogeneous shells, the shear load-deformation relations separate from in-plane behavior, and all the usual difficulties associated therewith disappear. The method for deriving in-plane constitutive relations for thick (t/R terms not negligible compared to unity), doubly curved, nonsymmetric shells with arbitrary-known sheet elastic-plastic behavior is presented. The form of the equations for yield and limit behavior is discussed, including yield surfaces and flow laws. Comparison of thin versus thick shell theory shows that nonconservative strength predictions can result from neglecting t/R terms. Use of the theory is illustrated by an example which shows application to fibrous composite materials and the effect of shell thickness.

A Simplified Analysis Method for Complex Piping Systems in Elastic-Plastic-Creep Range

1985 ◽  
Vol 107 (2) ◽  
pp. 148-156
Author(s):  
O. Watanabe ◽  
H. Ohtsubo
Keyword(s):  
Finite Element ◽  
Present Method ◽  
Constitutive Relations ◽  
Plastic Behavior ◽  
Piping System ◽  
Curved Beams ◽  
Elastic Plastic ◽  
Piping Systems ◽  
Creep Deformations ◽  
Plastic Creep

The present paper describes a simplified finite element method for analysis of behavior of complex piping systems under elevated temperature. Elastic-plastic-creep deformations of a piping system under a combined moment loading can be analyzed by the present method. The system is idealized by straight and curved beams, and derivation of the finite element equation is based on the force method. The unified constitutive relations are used for creep and plastic behavior, where plastic deformation is treated as a limiting case of creep. The numerical results are compared with previous experimental ones, which verifies the validity of the proposed method. Elastic follow-up problem of a piping system of actually complex configuration is also solved by the present method.

A Comparison Between Two Models That Predict the Elastic-Plastic Behavior of Particulate Metal Matrix Composites Under Multiaxial Fatigue Type Loading

Materials ◽  
2003 ◽  
Author(s):  
Gbadebo Moses Owolabi ◽  
Meera N. K. Singh
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Constitutive Relations ◽  
Multiaxial Fatigue ◽  
Cyclic Plasticity ◽  
Plastic Behavior ◽  
Matrix Composites ◽  
Elastic Plastic ◽  
Particulate Metal

This paper is an effort to first modify two cyclic plasticity models developed for homogeneous metals to address the heterogeneous nature of particulate metal matrix composites (PMMCs), and subsequently to evaluate the resulting relations both theoretically and experimentally. Specifically, using the original Mro´z model and the endochronic theory of plasticity as their bases, two sets of elastic-plastic constitutive relations are identified. These sets of relations account for the interaction in stress fields between adjacent particles in PMMCs. The behavior predicted by each model is compared with experimental results obtained from a series of uniaxial and biaxial (tension-torsion) tests performed on circular specimens made of the 6061/Al2O3/20p-T6 PMMCs with 20% volume fraction of particles. The materials are tested for a variety of applied monotonic and cyclic loading paths.

Elastic-Plastic Behavior of Filamentary Networks

2000 ◽  
Author(s):  
Eveline Baesu
Keyword(s):  
Plastic Deformation ◽  
Plastic Behavior ◽  
Thin Sheets ◽  
Equilibrium Equations ◽  
Elastic Plastic ◽  
Global Force ◽  
Incremental Formulation ◽  
Constitutive Properties ◽  
Material Points

Abstract The finite elastic-plastic deformation of thin sheets formed by several families of perfectly flexible extensible fibers is described using an idealized theory in which fibers are assumed to be continuously distributed and fastened together at nodes which deform as material points. The constitutive properties of the associated surface are deduced directly from those of the constituent fibers. An incremental formulation of the equilibrium equations for two families of fibers is presented and used to generate extremum principles based on primary bounds on the exact global force-deflection response.

Elastic-plastic behavior of coldworked holes

1983 ◽  
Author(s):  
H. ARMEN ◽  
A. LEVY ◽  
H. EIDINOFF
Keyword(s):  
Plastic Behavior ◽  
Elastic Plastic

scholarly journals Alternative derivation of the higher-order constitutive model for six-parameter elastic shells

2021 ◽  
Vol 72 (2) ◽  
Author(s):  
Mircea Bîrsan
Keyword(s):  
Energy Density ◽  
Constitutive Model ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Shell Theory ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Classical Shell Theory ◽  
Three Dimensional Elasticity ◽  
General Method

AbstractIn this paper, we present a general method to derive the explicit constitutive relations for isotropic elastic 6-parameter shells made from a Cosserat material. The dimensional reduction procedure extends the methods of the classical shell theory to the case of Cosserat shells. Starting from the three-dimensional Cosserat parent model, we perform the integration over the thickness and obtain a consistent shell model of order $$ O(h^5) $$ O ( h 5 ) with respect to the shell thickness h. We derive the explicit form of the strain energy density for 6-parameter (Cosserat) shells, in which the constitutive coefficients are expressed in terms of the three-dimensional elasticity constants and depend on the initial curvature of the shell. The obtained form of the shell strain energy density is compared with other previous variants from the literature, and the advantages of our constitutive model are discussed.

Approximate Macroscale Constitutive Relations Using a Finite Element Based Constitutive Equations for Microscale Contact

2008 ◽  
Author(s):  
Ali Sepehri ◽  
Kambiz Farhang
Keyword(s):  
Finite Element ◽  
Contact Force ◽  
Rough Surfaces ◽  
Constitutive Relations ◽  
Cumulative Effect ◽  
Element Model ◽  
Tangential Component ◽  
Total Force ◽  
Asperity Contact ◽  
Elastic Plastic

Three dimensional elastic-plastic contact of two nominally flat rough surfaces is considered. Equations governing the shoulder-shoulder contact of asperities are derived based on the asperity-asperity constitutive relations from a finite element model of their elastic-plastic interaction. Shoulder-shoulder asperity contact yields a slanted contact force consisting of both tangential (parallel to mean plane) and normal components. Multiscale modeling of the elastic-plastic rough surface contact is presented in which asperity-level FE-based constitutive relations are statistically summed to obtain total force in the normal and tangential direction. The equations derived are in the form of integral functions and provide expectation of contact force components between two rough surfaces. An analytical fusion technique is developed to combine the piecewise asperity level constitutive relations. This is shown to yield upon statistical summation the cumulative effect resulting in the contact force between two rough surfaces with two components, one in the normal direction and a half-plane tangential component.

Effect of Defect on Elastic/Plastic and Creep Behavior of Bone: A Finite Element Study

2007 ◽  
Author(s):  
A. Ajdari ◽  
P. K. Canavan ◽  
H. Nayeb-Hashemi ◽  
G. Warner
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Trabecular Bone ◽  
Fatigue Loading ◽  
Dimensional Structure ◽  
Plastic Behavior ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Local Bone ◽  
Osteoporotic Vertebral Fractures

Three-dimensional structure of trabecular bone can be modeled by 2D or 3D Voronoi structure. The effect of missing cell walls on the mechanical properties of 2D honeycombs is a first step towards understanding the effect of local bone resorption due to osteoporosis. In patients with osteoporosis, bone mass is lost first by thinning and then by resorption of the trabeculae [1]. Furthermore, creep response is important to analyze in cellular solids when the temperature is high relative to the melting temperature. For trabecular bone, as body temperature (38 °C) is close to the denaturation temperature of collagen (52 °C), trabecular bone creeps [1]. Over the half of the osteoporotic vertebral fractures that occur in the elderly, are the result of the creep and fatigue loading associated with the activities of daily living [2]. The objective of this work is to understand the effect of missing walls and filled cells on elastic-plastic behavior of both regular hexagonal and non-periodic Voronoi structures using finite element analysis. The results show that the missing walls have a significant effect on overall elastic properties of the cellular structure. For both regular hexagonal and Voronoi materials, the yield strength of the structure decreased by more than 60% by introducing 10% missing walls. In contrast, the results indicate that filled cells have much less effect on the mechanical properties of both regular hexagonal and Voronoi materials.

Thermal Annealing Effect on Elastic-Plastic Behavior of Al-Si-Cu Structural Films Under Uniaxial and Biaxial Tension

2013 ◽  
Vol 22 (6) ◽  
pp. 1414-1427 ◽  
Author(s):  
Takahiro Namazu ◽  
Masayuki Fujii ◽  
Hiroki Fujii ◽  
Kei Masunishi ◽  
Yasushi Tomizawa ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Biaxial Tension ◽  
Annealing Effect ◽  
Plastic Behavior ◽  
Elastic Plastic

Load Regime Diagram of a Pipe With Cyclically Plastic Bending

2002 ◽  
Author(s):  
Yanping Yao ◽  
Ming-Wan Lu
Keyword(s):  
Axial Force ◽  
Bending Moment ◽  
Boundary Curve ◽  
Plastic Behavior ◽  
Cyclic Bending ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Load Regime ◽  
Reversed Cyclic ◽  
Cyclic Bending Moment

The criteria of piping seismic design based on linear elastic analysis has been proved to be conservative, which is mainly because the influence of plastic deformation on piping dynamic response is neglected. In the present paper, a pipe under seismic excitation is simplified as an beam with tubular cross section subjected to steady axial force and fully reversed cyclic bending moment, and the elastic-plastic behavior of the pipe is studied. Various behavior of the pipe under different combinations of axial force and cyclic bending moment is discussed and the boundary curve equations between them are obtained. Also the load regime diagram for a pipe which is formed by the boundary curve equations in the loading plane is given, from which the elastic-plastic behavior of the pipe can be determined directly.

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