Consideration on Evaluation of Layered Material for Identification of Mechanical Characteristics in Horny layer by Indentation Test

Many industries, such as the biotechnology, food, and beauty industries, require noninvasive methods for quantifying material stiffness. One such method is the indentation test, which is particularly useful in evaluating the mechanical characteristics of soft materials. However, it is difficult to identify mechanical characteristics of the distinct layers of layered materials such as human skin due to their physical integration with one another. There is particular interest in evaluating the softness of the stratum corneum (the outermost layer of skin) in the cosmetics industry, where the effect of cosmetics should be restricted to this outermost layer. The purpose of this study was to develop a method to determine the elasticities and thicknesses of discrete layers in a layered material by using an indentation test. This paper discusses the results of this indentation test derived via the finite element method (FEM). Here, the finite element (FE) model is constructed by a layered structure of flat surfaces with given Young’s moduli. The FEM results suggest the existence of a law among the elasticities and layer thicknesses of a layered material.

Download Full-text

Abnormal Structural Strength of Topocomposites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.560-561.338 ◽

2012 ◽

Vol 560-561 ◽

pp. 338-343 ◽

Cited By ~ 1

Author(s):

Nikolay A. Voronin

Keyword(s):

Surface Layer ◽

Bearing Capacity ◽

Half Space ◽

Contact Interaction ◽

Solid Body ◽

Mechanical Characteristics ◽

Structural Strength ◽

Layered Material ◽

Thin Surface Layer ◽

Layer Coating

The mechanics of contact interaction of rigid spherical indenter with two-layer elastic - plastic half-space, simulating a surface of a solid body with a thin surface layer is considered. Analytical dependences of critical indentation and bearing capacity on mechanical characteristics of materials of a base and a coating, and as well as that for thickness of top layer (coating) in all region of possible thickness are received and analyzed. Existence of regions of the abnormal structural strength allowing the surface layered material to identify unequivocally as a topocomposite is shown. Theoretical dependences were verified by a final elements method.

Download Full-text

Sintering and Mechanical Properties of Alumina Ceramics Prepared by Nanosize Alumina

Materials Science Forum ◽

10.4028/www.scientific.net/msf.544-545.821 ◽

2007 ◽

Vol 544-545 ◽

pp. 821-824

Author(s):

Indra ◽

S.W. Oh ◽

Hee Joon Kim

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Relative Density ◽

Mechanical Characteristics ◽

Indentation Test ◽

Test System ◽

Alumina Ceramics ◽

New Materials ◽

Size Dependent

This work examined the mechanical properties of alumina that can directly be enhanced by ratio of nano sized alumina powders additives to micro size alumina powders (n/m ratio). These new materials have mechanical properties that are strongly grain size dependent and often significantly different from those of their coarser grained counter parts. The mechanical characteristics of samples were observed by using the indentation test system. This data shows that the relative density for the sample is increased with increasing Meyer hardness.

Download Full-text

Contribution to the Determination of In Vivo Mechanical Characteristics of Human Skin by Indentation Test

Computational and Mathematical Methods in Medicine ◽

10.1155/2013/814025 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 5

Author(s):

Marie-Angèle Abellan ◽

Hassan Zahouani ◽

Jean-Michel Bergheau

Keyword(s):

Human Skin ◽

Mechanical Characteristics ◽

Heterogeneous Media ◽

Indentation Test ◽

Stratified Medium ◽

Ionic Component ◽

Intact Skin ◽

Behaviour Law

This paper proposes a triphasic model of intact skin in vivo based on a general phenomenological thermohydromechanical and physicochemical (THMPC) approach of heterogeneous media. The skin is seen here as a deforming stratified medium composed of four layers and made out of different fluid-saturated materials which contain also an ionic component. All the layers are treated as linear, isotropic materials described by their own behaviour law. The numerical simulations of in vivo indentation test performed on human skin are given. The numerical results correlate reasonably well with the typical observations of indented human skin. The discussion shows the versatility of this approach to obtain a better understanding on the mechanical behaviour of human skin layers separately.

Download Full-text

Theoretical and Experimental Research on Mechanical Behavior of Layered Composites Laminates

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.657.432 ◽

2014 ◽

Vol 657 ◽

pp. 432-436

Author(s):

Bogdan Nicolae Ghitan ◽

Nicolae Florin Cofaru

Keyword(s):

Experimental Research ◽

Mechanical Characteristics ◽

Tensile Modulus ◽

Experimental Tests ◽

Maximum Load ◽

Layered Material ◽

Layered Composites ◽

Flexural Test ◽

Elongation At Break ◽

Maximum Voltage

The aim of the research of the experiment was to determine the mechanical characteristics of the composite layered material. There has been two types of experimental tests i.e. test for determining the tensile modulus of elasticity of the material, the maximum voltage and the elongation at break of the material. The second type of test is the flexural test was intended to determine the maximum load that the breaking is produced by bending.

Download Full-text

Paracrystalline Aggregates of Psoriatic Keratin and Their Relation to Normal Keratin Structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120096 ◽

1985 ◽

Vol 43 ◽

pp. 680-681

Author(s):

S. Trachtenberg ◽

P.M. Steinert ◽

B.L. Trus ◽

A.C. Steven

Keyword(s):

Cell Death ◽

Stratum Corneum ◽

Intermediate Filament ◽

Skin Disease ◽

Amorphous Matrix ◽

Terminal Differentiation ◽

Proteolytic Degradation ◽

Horny Layer ◽

Chronic Skin ◽

Chronic Skin Disease

During terminal differentiation of vertebrate epidermis, certain specific keratin intermediate filament (KIF) proteins are produced. Keratinization of the epidermis involves cell death and disruption of the cytoplasm, leaving a network of KIF embedded in an amorphous matrix which forms the outer horny layer known as the stratum corneum. Eventually these cells are shed (desquamation). Normally, the processes of differentiation, keratinization, and desquamation are regulated in an orderly manner. In psoriasis, a chronic skin disease, a hyperkeratotic stratum corneum is produced, resulting in abnormal desquamation of unusually large scales. In this disease, the normal KIF proteins are diminished in amount or absent, and other proteins more typical of proliferative epidermal cells are present. There is also evidence of proteolytic degradation of the KIF.

Download Full-text