Interfaces Behavior in Glued Granular Materials

2015 ◽  
Vol 665 ◽  
pp. 113-116
Author(s):  
Michele Buonsanti ◽  
Fortunato Ceravolo ◽  
Giovanni Leonardi ◽  
Francesco Scopelliti
Keyword(s):  
Granular Materials ◽  
Structural Integrity ◽  
High Surface ◽  
Volume Element ◽  
Model Specification ◽  
Scale Model ◽  
Critical Conditions ◽  
Stress And Strain ◽  
Strain Fields ◽  
Micro Scale

In this paper a micro-scale model to investigate the structural integrity of a runway surface has been developed. By performing stress analysis on a representative volume element (RVE), our model specification has been focalized on two elementary mixture constituents, two rigid components glued together by asphalt. The analysis is performed under thermo-mechanical actions, as those produced by landing gear impact and variable high surface temperatures. Three different interfaces (rigid to rigid, rigid to soft and soft to soft), three different asphalt density and two different values of surface temperature have been considered in the simulation. Resulting stress and strain fields are compared to define the greater critical conditions and to evaluate the micro-scale structural integrity

Homogenization of Out-of-Plane Loaded Random Plates

2010 ◽  
Vol 638-642 ◽  
pp. 2766-2771
Author(s):  
Karam Sab
Keyword(s):  
Composite Material ◽  
Boundary Conditions ◽  
Boundary Problem ◽  
Representative Volume Element ◽  
Plane Deformation ◽  
Infinite Plate ◽  
Volume Element ◽  
Stress And Strain ◽  
Strain Fields ◽  
Out Of Plane

The homogenization of elastic periodic plates is as follows: The 3D heterogeneous body is replaced by a homogeneous Love-Kirchhoff plate whose stiffness constants are computed by solving an auxiliary boundary problem on a 3D unit cell that generates the plate by periodicity in the in-plane directions. In the present study, a generalization of the above mentioned approach is presented for the random case. The homogenized bending stiffness and the moduli for in-plane deformation of a plate cut from a block of composite material, considered to be a statistically uniform random material in the in-plane directions, are defined in three equivalent manners: a) the first definition considers statistically invariant stress and strain fields in the infinite plate. In the second and third definitions, a finite representative volume element of the plate is submitted to suitable b) kinematically uniform boundary conditions and c) statically uniform boundary conditions. The relationships between these three definitions are studied and bounds are derived.

Micro-Macro Characterization of Granular Materials

2012 ◽  
Vol 598 ◽  
pp. 345-350
Author(s):  
Yan Qiong Zhang ◽  
Xiao Min Xu ◽  
Dao Sheng Ling
Keyword(s):  
Granular Materials ◽  
Strain Tensor ◽  
Volume Element ◽  
Fabric Tensor ◽  
Micro Scale ◽  
Macro Scale ◽  
Intrinsic Complexity ◽  
Force Contact ◽  
Contact Displacement

The intrinsic complexity of granular materials stems from the fact that the characterizing variables at the micro-scale and the macro-scale are of different nature. Macroscopically, tensorial variables (stress tensor, strain tensor, fabric tensor) are commonly used based on Representative Volume Element (RVE), while vectorial variables (contact force, contact displacement, contact normal) are adopted at particle-scale. This paper mainly discusses some basic characterizations for these two scales, as well as their correlations. Numerical simulations using Discrete Element Method (DEM) are then conducted to show the evolutions of both microscopic and macroscopic variables during monotonic loading. It is indicated that the particle reorientations in the dense sample are much more pronounced than that in the loose one during shearing.

Mathematical Model of the Effective Properties of a Fiber Reinforced Composite with a Linearly Graded Transition Zone

2010 ◽  
Vol 38 (4) ◽  
pp. 286-307
Author(s):  
Carey F. Childers
Keyword(s):  
Mathematical Model ◽  
Transition Zone ◽  
Effective Properties ◽  
Local Stress ◽  
Stress And Strain ◽  
Fiber Reinforced ◽  
Strain Fields ◽  
Shear Moduli ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Abstract Tires are fabricated using single ply fiber reinforced composite materials, which consist of a set of aligned stiff fibers of steel material embedded in a softer matrix of rubber material. The main goal is to develop a mathematical model to determine the local stress and strain fields for this isotropic fiber and matrix separated by a linearly graded transition zone. This model will then yield expressions for the internal stress and strain fields surrounding a single fiber. The fields will be obtained when radial, axial, and shear loads are applied. The composite is then homogenized to determine its effective mechanical properties—elastic moduli, Poisson ratios, and shear moduli. The model allows for analysis of how composites interact in order to design composites which gain full advantage of their properties.

Localization simulation of forming-induced residual stresses of composite using prescribed boundary

2021 ◽  
pp. 073168442094118
Author(s):  
Qi Wu ◽  
Hongzhou Zhai ◽  
Nobuhiro Yoshikawa ◽  
Tomotaka Ogasawara ◽  
Naoki Morita
Keyword(s):  
Residual Stresses ◽  
Representative Volume Element ◽  
Computational Cost ◽  
Volume Element ◽  
Thermoplastic Composite ◽  
Structural Deformation ◽  
Element Analysis ◽  
Micro Scale ◽  
Representative Volume ◽  
Localization Approach

A novel localization approach that seamlessly bridges the macro- and micro-scale models is proposed and used to model the forming-induced residual stresses within a representative volume element of a fiber reinforced composite. The approach uses a prescribed boundary that is theoretically deduced by integrating the asymptotic expansion of a composite and the equal strain transfer, thus rendering the simulation setting to be easier than conventional approaches. When the localization approach is used for the finite element analysis, the temperature and residual stresses within an ideal cubic representative volume element are precisely simulated, given a sandwiched thermoplastic composite is formed under one-side cooling condition. The simulation results, after being validated, show that the temperature gradient has an impact on the local residual stresses, especially on the in-plane normal stress transverse to the fiber, and consequently, influences the structural deformation. This newly designed localization approach demonstrates the advantages of enhanced precision and reduced computational cost owing to the fast modeling of the finely meshed representative volume element. This is beneficial for a detailed understanding of the actual residual stresses at the micro-scale.

The stress and strain fields in the neighbourhood of a notch in polyethylene

Polymer ◽  
1989 ◽  
Vol 30 (8) ◽  
pp. 1456-1461 ◽  
Author(s):  
Xue-qin Wang ◽  
Norman Brown
Keyword(s):  
Stress And Strain ◽  
Strain Fields

Endochronic Analysis of Cyclic Elastoplastic Strain Fields in a Notched Plate

1983 ◽  
Vol 50 (4a) ◽  
pp. 789-794 ◽  
Author(s):  
K. C. Valanis ◽  
J. Fan
Keyword(s):  
Residual Stress ◽  
Numerical Scheme ◽  
External Loading ◽  
Stress And Strain ◽  
Elastoplastic Strain ◽  
Residual Stress Field ◽  
Progressive Change ◽  
Strain Fields ◽  
Cyclic Tension ◽  
Cyclic Elastoplastic Strain

In this paper we present an analytical cum-numerical scheme, based on endochronic plasticity and the finite element formalism. The scheme is used to calculate the stress and elastoplastic strain fields in a plate loaded cyclically in its own plane along its outer edges and bearing two symmetrically disposed edge notches. One most important result that stands out is that while the external loading conditions are symmetric and periodic, the histories of stress and strain at the notch tip are neither symmetric nor periodic in character. In cyclic tension ratcheting phenomena at the tip of the notches prevail and a progressive change of the residual stress field at the notch line is shown to occur.

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