scholarly journals Evaluation of different approaches to 3d numerical model development of the contact zone between elementary asperities and flat surface

2017 ◽  
Vol 4 (17) ◽  
pp. 40-53 ◽  
Author(s):  
Pawel MACIOLKA ◽  
Jerzy JEDRZEJEWSKI
Keyword(s):  
Contact Zone ◽  
Flat Surface ◽  
Model Development ◽  
Real Surface ◽  
Contact Loading ◽  
The Real ◽  
Subsurface Zone ◽  
Elastoplastic Properties ◽  
Quarter Model ◽  
Contact Characteristic

This paper presents two triaxial finite element (FE) models: a “full model” and a “quarter model”, representing the contact between the specimen’s rough surface and the ideally smooth and flat surface of the punch. Models have a contact zone that represents the topography of the real surface and has elastoplastic properties close to those of the real contact. The contact zone was entirely modelled on the basis of roughness measurements performed on a real milled specimen made of 5083 aluminium alloy. The development of the FE models, the stages in their refinement and the interlinking of the contact zone with the material of the specimen are described. The results of the computed deformations occurring during the specimen contact loading with the punch were compared with the experimental results. The possible causes of the observed deviations of the computer simulation results from the experimental ones were discussed. The models were used to analyse the effect of the specimen’s material properties, i.e. Young’s modulus, yield strength, compressive strength and material hardening, on the deformations in the contact. On this basis a procedure for predicting the parameters describing the contact characteristic in cases of changes in the properties of the subsurface zone is proposed

Scanning electron microscopy of human iliac bone by a simple preparation method

1990 ◽  
Vol 48 (3) ◽  
pp. 226-227
Author(s):  
Toshihiko Takita ◽  
Tomonori Naguro ◽  
Toshio Kameie ◽  
Akihiro Iino ◽  
Kichizo Yamamoto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Real Surface ◽  
Public Attention ◽  
Preparation Methods ◽  
The Real ◽  
Simple Preparation ◽  
Scanning Electron

Recently with the increase in advanced age population, the osteoporosis becomes the object of public attention in the field of orthopedics. The surface topography of the bone by scanning electron microscopy (SEM) is one of the most useful means to study the bone metabolism, that is considered to make clear the mechanism of the osteoporosis. Until today many specimen preparation methods for SEM have been reported. They are roughly classified into two; the anorganic preparation and the simple preparation. The former is suitable for observing mineralization, but has the demerit that the real surface of the bone can not be observed and, moreover, the samples prepared by this method are extremely fragile especially in the case of osteoporosis. On the other hand, the latter has the merit that the real information of the bone surface can be obtained, though it is difficult to recognize the functional situation of the bone.

Mathematical Model of Flat Surface Machining Inaccuracies due to Elastic Strains of Technological System

2018 ◽  
pp. 1-14 ◽  
Author(s):  
I. I. Kravchenko
Keyword(s):  
Mathematical Model ◽  
Vector Field ◽  
Model Development ◽  
Technological System ◽  
Mutual Arrangement ◽  
Real Surface ◽  
Main Bearing ◽  
Flat Surfaces ◽  
Internal Surfaces ◽  
Elastic Strains

The paper considers the mathematical model development technique to build a vector field of the shape deviations when machining flat surfaces of shell parts on multi-operational machines under conditions of anisotropic rigidity in technological system (TS). The technological system has an anisotropic rigidity, as its elastic strains do not obey the accepted concepts, i.e. the rigidity towards the coordinate axes of the machine is the same, and they occur only towards the external force. The record shows that the diagrams of elastic strains of machine units are substantially different from the circumference. The issues to ensure the specified accuracy require that there should be mathematical models describing kinematic models and physical processes of mechanical machining under conditions of the specific TS. There are such models for external and internal surfaces of rotation [2,3], which are successfully implemented in practice. Flat surfaces (FS) of shell parts (SP) are both assembly and processing datum surfaces. Therefore, on them special stipulations are made regarding deviations of shape and mutual arrangement. The axes of the main bearing holes are coordinated with respect to them. The joints that ensure leak tightness and distributed load on the product part are closed on these surfaces. The paper deals with the analytical construction of the vector field F, which describes with appropriate approximation the real surface obtained as a result of modeling the process of machining flat surfaces (MFS) through face milling under conditions of anisotropic properties.

Identification and Minimization of Deviations of Real Gear Tooth Surfaces

1989 ◽  
Author(s):  
F. L. Litvin ◽  
Y. Zhang ◽  
J. Kieffer ◽  
R. F. Handschuh
Keyword(s):  
Machine Tool ◽  
Gear Tooth ◽  
Real Surface ◽  
The Real ◽  
Tooth Surfaces ◽  
Coordinate Measurements

Abstract The authors propose an approach that uses coordinate measurements of the real surface to: (i) determine the real applied machine-tool settings, (ii) determine the deviations of the real surface from the theoretical one, (iii) minimize the deviations by correction of the machine-tool settings, and (iv) represent the real surface analytically in the same Gaussian coordinates as the theoretical one.

scholarly journals A Study on Generic Representation of Skeletal Remains Replication of Prehistoric Burial

2015 ◽  
Vol XL-5/W7 ◽  
pp. 379-386
Author(s):  
C.-W. Shao ◽  
H.-L. Chiu ◽  
S.-K. Chang
Keyword(s):  
Rapid Prototyping ◽  
Surface Texture ◽  
Colour Change ◽  
3D Scanning ◽  
Skeletal Remains ◽  
Real Surface ◽  
Neolithic Period ◽  
Human Skeletal Remains ◽  
The Real ◽  
Generic Representation

Generic representation of skeletal remains from burials consists of three dimensions which include physical anthropologists, replication technicians, and promotional educators. For the reason that archaeological excavation is irreversible and disruptive, detail documentation and replication technologies are surely needed for many purposes. Unearthed bones during the process of 3D digital scanning need to go through reverse procedure, 3D scanning, digital model superimposition, rapid prototyping, mould making, and the integrated errors generated from the presentation of colours and textures are important issues for the presentation of replicate skeleton remains among professional decisions conducted by physical anthropologists, subjective determination of makers, and the expectations of viewers. This study presents several cases and examines current issues on display and replication technologies for human skeletal remains of prehistoric burials. <br><br> This study documented detail colour changes of human skeleton over time for the reference of reproduction. The tolerance errors of quantification and required technical qualification is acquired according to the precision of 3D scanning, the specification requirement of rapid prototyping machine, and the mould making process should following the professional requirement for physical anthropological study. Additionally, the colorimeter is adopted to record and analyse the “colour change” of the human skeletal remains from wet to dry condition. Then, the “colure change” is used to evaluate the “real” surface texture and colour presentation of human skeletal remains, and to limit the artistic presentation among the human skeletal remains reproduction. <br><br> The“Lingdao man No.1”, is a well preserved burial of early Neolithic period (8300 B.P.) excavated from Liangdao-Daowei site, Matsu, Taiwan , as the replicating object for this study. In this study, we examined the reproduction procedures step by step for ensuring the surface texture and colour of the replica matches the real human skeletal remains when discovered. The “colour change” of the skeleton documented and quantified in this study could be the reference for the future study and educational exhibition of human skeletal remain reproduction.

Determination of the Real Surface Area of Palladium Electrode

2010 ◽  
Vol 23 (5) ◽  
pp. 543-548 ◽  
Author(s):  
Lan-lan Fang ◽  
Qian Tao ◽  
Ming-fang Li ◽  
Ling-wen Liao ◽  
Dong Chen ◽  
...  
Keyword(s):  
Surface Area ◽  
Real Surface ◽  
The Real ◽  
Palladium Electrode ◽  
Real Surface Area

scholarly journals Modelling of Level Process

2019 ◽  
Vol 8 (11) ◽  
pp. 1155-1161
Keyword(s):  
Real Time ◽  
Empirical Model ◽  
First Principles ◽  
Model Development ◽  
The Real ◽  
Development Models ◽  
System A ◽  
Basic Physics ◽  
Tank System ◽  
Operating Points

Industries such as, textile, food processing, chemical and water treatment plants are part of our global development. The efficiency of processes used by them is always a matter of great importance. Efficiency can be greatly improved by obtaining an exact model of the process. This paper studies the two main classifications of model development – First-Principles Model and Empirical Model. First-Principles Model can be obtained with an understanding of the basic physics of the system. On the other hand, Empirical Models require only the input-output data and can thus factor in process non-linearity, disturbances and unexpected errors. This paper utilizes the System Identification Toolbox in MATLAB for empirical model development. Models are developed for a single tank system, a classic SISO problem and for the two interacting tank system. Both systems are studied with respect to three operating points, each from a local linear region. The obtained models are validated with the real-time setup. They are satisfactory in their closeness to the real time process and hence deemed fit for use in control algorithms and other process manipulations

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