scholarly journals Study of mechanical behavior and internal structure of ferritic nanocrystalline material

1992 ◽  
Author(s):  
J.R. Weertman ◽  
W.P. Murphy
Keyword(s):  
Mechanical Behavior ◽  
Internal Structure ◽  
Nanocrystalline Material

Representation of Mechanical Behavior in the Presence of Changing Internal Structure

1988 ◽  
Vol 55 (1) ◽  
pp. 1-10 ◽  
Author(s):  
E. T. Onat ◽  
F. A. Leckie
Keyword(s):  
Mechanical Behavior ◽  
Internal Structure ◽  
Applied Stress ◽  
Constitutive Equations ◽  
Creep Damage ◽  
Main Ideas ◽  
The Relationship ◽  
Small Deformations

The paper is concerned with the representation of the relationship that exists, for a given material and temperature and for small deformations, between histories of applied stress and the observed strain and the accompanying changes in internal structure of the material. Emphasis is given to creep damage in metals as a vehicle for illustration of the main ideas introduced in the paper. In particular, the role played by irreducible even rank tensors in the representation of internal structure is discussed and clarified. The restrictions placed by thermodynamics on constitutive equations are considered and the use of potentials in these equations is examined and criticized.

scholarly journals Structure investigations of layered soil – varved clay

2016 ◽  
Vol 48 (4) ◽  
pp. 365-375 ◽  
Author(s):  
Matylda Tankiewicz
Keyword(s):  
Mechanical Behavior ◽  
Internal Structure ◽  
Strength Properties ◽  
Layered Soil ◽  
Radiographic Images ◽  
Composition And Structure ◽  
Computed Microtomography ◽  
Structure Investigations ◽  
Varved Clay

Abstract In the paper the results of laboratory investigations of structure of layered soil are presented. They focus on varved clay that is a soil composed of two alternately arranged varves with different texture and mechanical properties. An effect of such structure is an anisotropy of the material. Due to varying conditions during its formation process the soil exhibits some irregularities in composition and structure. Due to that modelling of mechanical behavior, like strength, may not provide satisfactory results. Main purpose of the examinations is an investigation of internal structure of layered soil – varved clay – in relation to its strength anisotropy and evaluation of the suitability of the use of two different techniques to assess the soil structure. Investigated material have been taken from area near city of Bełchatów in central Poland. The examinations included investigation of particle size distribution of soil and its components, identification of lamination with use of scanning electron microscope (SEM) and computed microtomography technique (μCT). First, the texture of each varve and varved clay as a composite have been estimated. Next, the investigation of surface perpendicular to the lamination have been carried out with SEM. Pictures of varves with different magnifications are presented. Also the varves arrangement and details of layers contact area are shown. Finally, investigation of internal structure of the soil have been performed by using microtomograph. The outcome is a series of radiographic images and reconstructed 3D model of tested soil. Presented results show complexity of the structure of varved clay that affect the mechanical behavior. Determination of the structure with use of presented techniques may be helpful in examination of strength properties and proper modeling of such soil.

scholarly journals Mechanical behavior of a hydrated perfluorosulfonic acid membrane at meso and nano scales

RSC Advances ◽  
2019 ◽  
Vol 9 (17) ◽  
pp. 9594-9603 ◽  
Author(s):  
Cong Feng ◽  
Yan Li ◽  
Kunnan Qu ◽  
Zhiming Zhang ◽  
Pengfei He
Keyword(s):  
Mechanical Properties ◽  
Fuel Cells ◽  
Mechanical Behavior ◽  
Internal Structure ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Membrane Material ◽  
Perfluorosulfonic Acid ◽  
The Stability ◽  
Exchange Membrane

Perfluorosulfonic acid (PFSA) is widely used as the membrane material for proton-exchange membrane fuel cells, and its mechanical properties directly affect the stability and the life of the internal structure of the proton exchange membrane.

scholarly journals Macroscopic Behavior and Microscopic Structure Evolution of Marine Clay in One-Dimensional Compression Revealed by Discrete Element Simulation

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2259
Author(s):  
Lisha Luo ◽  
Zhifu Shen ◽  
Hongmei Gao ◽  
Zhihua Wang ◽  
Xin Zhou
Keyword(s):  
Mechanical Behavior ◽  
Internal Structure ◽  
Formation Process ◽  
Discrete Element ◽  
Structure Evolution ◽  
Microscopic Structure ◽  
Marine Clay ◽  
Dem Simulation ◽  
One Dimensional ◽  
Simulation Scheme

Marine clay has been attracting in-depth research on its mechanical behavior and internal structure evolution, which are crucial to marine infrastructure safety. In the formation process of marine clay, including the sedimentation and consolidation stages, the compression behavior and internal structure evolution are highly dependent on the pore water salinity. Discrete element method (DEM) simulation is a powerful tool to study the microscopic mechanics behind the complicated macroscopic mechanical behavior of marine clay. In this study, a DEM simulation scheme is systematically proposed to numerically study the macroscopic beahvior and microscopic structure evolution of marine clay in one-dimensional compression that mimics the marine clay formation process. First, the proposed calculation scheme for double layer repulsive interaction and van der Waals interaction is introduced. Then, the developed DEM simulation scheme is validated by satisfactorily reproducing the experimentally observed one-dimensional compression curves and internal structure transition from an edge-to-edge/edge-to-face flocculated structure to a face-to-face dispersed structure. Finally, evolutions of coordinate number and fabric anisotropy are quantitatively evaluated in the microscopic view. The noticeable effects of ion concentration on the internal structure evlotion and mechanical behavior of marine clay have been examined and discussed.

Variational Viscoelastic-Damage Model for Fiber Reinforced Soft Tissues

2013 ◽  
Author(s):  
Eduardo A. Fancello ◽  
Jakson M. Vassoler
Keyword(s):  
Mechanical Behavior ◽  
Internal Structure ◽  
Soft Tissues ◽  
Damage Model ◽  
Potential Functions ◽  
Ground Substance ◽  
Mullins Effect ◽  
Numerical Examples ◽  
Proposed Model ◽  
Dissipative Material

Connective soft tissues have a pronounced anisotropic mechanical behavior due to their internal structure, consisting of a quasi isotropic ground substance and anisotropic reinforcement based mostly in elastin and collagen fibers. The objective of this paper is to extend previously proposed model for viscoelastic materials with fiber reinforcement making it capable to represent two important phenomena: the so-called Mullins effect and the softening at excessive strains. The model is based on a variational, thermodynamical consistent framework based on an incremental potential that allows for the representation of different dissipative material by simply changing the expression of potential functions and for the obtention of symmetric constitutive tangent matrices. Numerical examples show the capability of the proposed model to mimic with appreciable accuracy the experimentally observed mechanical behavior of soft tissues.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

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