Numerical Evaluation of Recalling Elasticity due to Surface Roughness by Finite Element Modeling of Human Skin

2019 ◽  
Author(s):  
Tomohisa Yamamoto ◽  
Atsushi Sakuma
Keyword(s):  
Surface Roughness ◽  
Finite Element ◽  
Human Skin ◽  
Tactile Perception ◽  
Maximum Pressure ◽  
Skin Model ◽  
Solid Objects ◽  
Pitch Ratio ◽  
The Relationship ◽  
Maximum Inclination

Abstract Among human sensations, tactile perception has an important role in physics and in living comfortably. It is already known that surface roughness greatly affects the feel of solid objects, but the mechanics of the relationship between feeling and physics, as well as their effects, are difficult to determine. This study, aims to clarify the numerical relationship between elastic tactile perception and surface roughness of a rigid body by designing various products with surfaces comfortable to touch. The finite element method (FEM) has been adopted for this clarification, and a numerical model of human skin with 3 layers, epidermis, dermis, and subcutaneous, has been developed to discuss the mechanical effects of touch movement. This skin model is used to evaluate the distribution of skin deformations during the process of touch movement, and the analysis of the tactile perception is done by discussing the distribution change due to touching objects. The change in distribution of deformation is mainly discussed in terms of pressure under the epidermis, and various patterns of distribution are inspected by changing the diameters and pitch ratio of a uniformly spread ball used as a plain surface. By comparing the relationship between distributions of rigid and elastic surfaces, similar distributions of pressure in the skin model were observed, and the relationships of the distribution are summarized to solve the mechanics of touch feeling. In this summarization, the maximum pressure and the maximum gradient of pressure distribution are adopted as parameters for the analysis. The analysis shows that it is numerically possible to represent the elasticity recalled by the rigid surface from its relationship with the elastic surface when they have the same maximum pressure and maximum inclination of pressure. The importance of maximum inclination of pressure for touch feeling is also shown here.

Model Simulating the Heat Transfer of Skin

2014 ◽  
Vol 3 (2) ◽  
pp. 42-58 ◽  
Author(s):  
Anders Jarløv ◽  
Tim Toftgaard Jensen
Keyword(s):  
Heat Transfer ◽  
Human Skin ◽  
Blood Perfusion ◽  
Electrical Model ◽  
Skin Model ◽  
Transfer Rates ◽  
Electric Circuits ◽  
Analogue Models ◽  
The Relationship

The relationship between surface temperature and heat transfer in a section of isotropic material with plane parallel sides, in this context simulating human skin, can be attained by means of analogue models. A model, in the form of electric circuits, enables the analogue functions to be recorded as electrical signals. Analogue heat transfer rates derived by processing voltage data from the models can be used for the determination of analogue measures of blood perfusion of the skin, which is generally stated in terms of ml blood flow per 100 ml tissue per minute. Analogue time scales can be compressed, reducing recording times of analogue functions, and inaccessible sites of actual tissues can be made accessible for observation in a model version. Lengthy calculations and the development of formulas can be substituted with the recording of analogue functions. The ability of a perfusable material to simulate the skin model is estimated by how well the material, when subjected to known perfusions with water, exhibit surface temperatures that agree with the corresponding analogue properties of the electrical model. The materials and methods are tentatively applied to recordings of perfusion of human skin.

Crystal Plasticity Finite Element Modelling of the Influence of Friction on Surface Roughening during Uniaxial Planar Compression

2010 ◽  
Vol 654-656 ◽  
pp. 1606-1609 ◽  
Author(s):  
Hei Jie Li ◽  
Zheng Yi Jiang ◽  
Dong Bin Wei ◽  
Jing Tao Han ◽  
A. Kiet Tieu
Keyword(s):  
Surface Roughness ◽  
Finite Element ◽  
Metal Forming ◽  
Finite Element Modelling ◽  
Element Model ◽  
Surface Roughening ◽  
Crystal Plasticity Finite Element ◽  
Finite Element Software ◽  
Key Factor ◽  
The Relationship

The friction is a key factor that influences the surface quality in metal forming. To figure out the relationship between the friction and the surface roughening, a finite element model is employed in the commercial finite element software ABAQUS to simulate the surface roughness of top side of Al plate during uniaxial planar compression. With the change of friction conditions, the surface roughening varies. The average surface roughness (Ra) shows a relationship with the friction coefficient. During the surface roughening process, the grain slip takes place in the “soft orientation”, and the “hard orientations” become the barrier of the slip.

Effects of Load, Speed, and Surface Roughness on Sliding EHD Contact Temperatures

1977 ◽  
Vol 99 (2) ◽  
pp. 254-261 ◽  
Author(s):  
H. S. Nagaraj ◽  
D. M. Sanborn ◽  
W. O. Winer
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
High Frequency ◽  
Point Contact ◽  
Temperature Measurements ◽  
Maximum Pressure ◽  
Surface Temperatures ◽  
Ball Surface ◽  
The Relationship ◽  
Frequency Temperature

An infrared technique has been used to determine the effects of load, speed and surface roughness on temperature in a sliding EHD point contact. Ball surface temperatures are reported for sliding speeds of 0.35 to 5.08 m/s at 0.52 to 2.03 GN/m2 maximum pressure with surface roughness in the range 0.01 to 0.38 μm c.1.a. The relationship between asperity interaction, as measured by relocation surface profilimetry and high frequency temperature measurements, and the ratio of film thickness to surface roughness has also been studied.

Analysis of magnetic force and dynamic characteristic for non-contact permanent magnet linear drive device

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1337-1345
Author(s):  
Chuan Zhao ◽  
Feng Sun ◽  
Junjie Jin ◽  
Mingwei Bo ◽  
Fangchao Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Dynamic Characteristic ◽  
Driving Force ◽  
Magnetic Circuit ◽  
Response Speed ◽  
Computation Method ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper proposes a computation method using the equivalent magnetic circuit to analyze the driving force for the non-contact permanent magnet linear drive system. In this device, the magnetic driving force is related to the rotation angle of driving wheels. The relationship is verified by finite element analysis and measuring experiments. The result of finite element simulation is in good agreement with the model established by the equivalent magnetic circuit. Then experiments of displacement control are carried out to test the dynamic characteristic of this system. The controller of the system adopts the combination control of displacement and angle. The results indicate that the system has good performance in steady-state error and response speed, while the maximum overshoot needs to be reduced.

Possible examinations of stone machining focused on the relationship between technological parameters and surface quality

2013 ◽  
Vol 4 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Zs. Kun ◽  
I. G. Gyurika
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Theoretical Background ◽  
Motion Path ◽  
Depth Of Cut ◽  
Manufacturing Cost ◽  
Technological Parameters ◽  
The Relationship ◽  
Manufacturing Time

Abstract The stone products with different sizes, geometries and materials — like machine tool's bench, measuring machine's board or sculptures, floor tiles — can be produced automatically while the manufacturing engineer uses objective function similar to metal cutting. This function can minimise the manufacturing time or the manufacturing cost, in other cases it can maximise of the tool's life. To use several functions, manufacturing engineers need an overall theoretical background knowledge, which can give useful information about the choosing of technological parameters (e.g. feed rate, depth of cut, or cutting speed), the choosing of applicable tools or especially the choosing of the optimum motion path. A similarly important customer's requirement is the appropriate surface roughness of the machined (cut, sawn or milled) stone product. This paper's first part is about a five-month-long literature review, which summarizes in short the studies (researches and results) considered the most important by the authors. These works are about the investigation of the surface roughness of stone products in stone machining. In the second part of this paper the authors try to determine research possibilities and trends, which can help to specify the relation between the surface roughness and technological parameters. Most of the suggestions of this paper are about stone milling, which is the least investigated machining method in the world.

Contact Analysis of Tire Tread Rubber on Flat Surface with Microscopic Roughness3

2006 ◽  
Vol 34 (4) ◽  
pp. 237-255 ◽  
Author(s):  
M. Kuwajima ◽  
M. Koishi ◽  
J. Sugimura
Keyword(s):  
Surface Roughness ◽  
Finite Element ◽  
Sliding Friction ◽  
Tangential Force ◽  
Partial Slip ◽  
Real Contact Area ◽  
Element Analysis ◽  
Real Contact ◽  
Local Slip ◽  
Tread Rubber

Abstract This paper describes experimental and analytical studies of the dependence of tire friction on the surface roughness of pavement. Abrasive papers were adopted as representative of the microscopic surface roughness of pavement surfaces. The rolling∕sliding friction of tire tread rubber against these abrasive papers were measured at low slip velocities. Experimental results indicated that rolling∕sliding frictional characteristics depended on the surface roughness. In order to examine the interfacial phenomena between rubber and the abrasive papers, real contact length, partial slip, and apparent friction coefficient under vertical load and tangential force were analyzed with two-dimensional explicit finite element analysis in which slip-velocity-dependent frictional coefficients were considered. Finite element method results indicated that the sum of real contact area and local partial slip were larger for finer surfaces under the same normal and tangential forces. In addition, the velocity-dependent friction enhanced local slip, where the dependence of local slip on surface roughness was pronounced. It proved that rolling∕sliding friction at low slip ratio was affected by local frictional behavior at microslip regions at asperity contacts.

Development and evaluation of trans-Amadi groundwater parameters: The integration of finite element techniques

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Finite Element ◽  
Polynomial Regression ◽  
Nitrate Concentration ◽  
Strong Relationship ◽  
Total Iron ◽  
Coefficient Of Determination ◽  
Port Harcourt ◽  
Polynomial Expression ◽  
The Relationship ◽  
Best Fit

Mathematical model was developed and evaluated to monitor and predict the groundwater characteristics of Trans-amadi region in Port Harcourt City. In this research three major components were considered such as chloride, total iron and nitrate concentration as well as the polynomial expression on the behavious on the concentration of each component was determined in terms of the equation of the best fit as well as the square root of the curve. The relationship between nitrate and distance traveled by Nitrate concentration by the model is given as Pc = 0.003x2 - 0.451x + 14.91with coefficient of determination, R² = 0.947, Chloride given as Pc = 0.000x2 - 0.071x + 2.343, R² = 0.951while that of Total Iron is given as Pc = 2E-05x2 - 0.003x + 0.110, R² = 0.930. All these show a strong relationship as established by Polynomial Regression Model. The finite element techniques are found useful in monitoring, predicting and simulating groundwater characteristics of Trans-amadi as well as the prediction on the variation on the parameters of groundwater with variation in time.

scholarly journals Downscaled Finite Element Modeling of Metal Targets for Surface Roughness Level under Pulsed Laser Irradiation

2021 ◽  
Vol 11 (3) ◽  
pp. 1253
Author(s):  
Evaggelos Kaselouris ◽  
Kyriaki Kosma ◽  
Yannis Orphanos ◽  
Alexandros Skoulakis ◽  
Ioannis Fitilis ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Finite Element ◽  
Surface Acoustic Waves ◽  
Pulsed Laser ◽  
Multiscale Simulation ◽  
Experimental Methodology ◽  
Computational Domain ◽  
Area Of Interest ◽  
Depth Analysis ◽  
Laser Solid Interactions

A three-dimensional, thermal-structural finite element model, originally developed for the study of laser–solid interactions and the generation and propagation of surface acoustic waves in the macroscopic level, was downscaled for the investigation of the surface roughness influence on pulsed laser–solid interactions. The dimensions of the computational domain were reduced to include the laser-heated area of interest. The initially flat surface was progressively downscaled to model the spatial roughness profile characteristics with increasing geometrical accuracy. Since we focused on the plastic and melting regimes, where structural changes occur in the submicrometer scale, the proposed downscaling approach allowed for their accurate positioning. Additionally, the multiscale simulation results were discussed in relation to experimental findings based on white light interferometry. The combination of this multiscale modeling approach with the experimental methodology presented in this study provides a multilevel scientific tool for an in-depth analysis of the influence of heat parameters on the surface roughness of solid materials and can be further extended to various laser–solid interaction applications.

scholarly journals Disinfectant effectiveness against SARS-CoV-2 and influenza viruses present on human skin: model-based evaluation

2021 ◽  
Author(s):  
Ryohei Hirose ◽  
Risa Bandou ◽  
Hiroshi Ikegaya ◽  
Naoto Watanabe ◽  
Takuma Yoshida ◽  
...  
Keyword(s):  
Human Skin ◽  
Influenza Viruses ◽  
Skin Model ◽  
Model Based

scholarly journals Inlay-Retained Dental Bridges—A Finite Element Analysis

2021 ◽  
Vol 11 (9) ◽  
pp. 3770
Author(s):  
Monica Tatarciuc ◽  
George Alexandru Maftei ◽  
Anca Vitalariu ◽  
Ionut Luchian ◽  
Ioana Martu ◽  
...  
Keyword(s):  
Finite Element ◽  
Young Patients ◽  
Maximum Pressure ◽  
Class Iii ◽  
Element Analysis ◽  
Dental Prostheses ◽  
Abutment Teeth ◽  
Fixed Dental Prostheses ◽  
Implant Therapy ◽  
The Stability

Inlay-retained dental bridges can be a viable minimally invasive alternative when patients reject the idea of implant therapy or conventional retained full-coverage fixed dental prostheses, which require more tooth preparation. Inlay-retained dental bridges are indicated in patients with good oral hygiene, low susceptibility to caries, and a minimum coronal tooth height of 5 mm. The present study aims to evaluate, through the finite element method (FEM), the stability of these types of dental bridges and the stresses on the supporting teeth, under the action of masticatory forces. The analysis revealed the distribution of the load on the bridge elements and on the retainers, highlighting the areas of maximum pressure. The results of our study demonstrate that the stress determined by the loading force cannot cause damage to the prosthetic device or to abutment teeth. Thus, it can be considered an optimal economical solution for treating class III Kennedy edentation in young patients or as a provisional pre-implant rehabilitation option. However, special attention must be paid to its design, especially in the connection area between the bridge elements, because the connectors and the retainers represent the weakest parts.

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