DETERMINATION OF THE RATIONAL SHAPE AND PARAMETERS OF THE ARTICULATION OF THE SPLIT COLLET OF THE CLAMPING MANDREL TO EXPAND ITS TECHNOLOGICAL CAPABILITIES

2020 ◽  
pp. 23-36
Author(s):  
P. V. Klakotsky ◽  
D. S. Blinov
Keyword(s):  
Practical Interest ◽  
Technological Capabilities ◽  
The Finite Element Method ◽  
Traditional Design ◽  
Equal Strength ◽  
Wide Range ◽  
Strength Based ◽  
Rational Shape ◽  
Maximum Stresses

The object of research is perspective mandrels with the pince fendues used for installing blanks such as rings, bushings and cups. These machine accessories are both high-precision and wide-range, but in previous articles it was found that there are reserves for expanding their technological capabilities. It was found that the shape and size of the articulation are key parameters and they significantly affect the allowable compression of the collet and its strength. Therefore, in this article, the finite element method solves the problem of determining the rational shape and parameters of the articulation to increase the compression of the collet while maintaining strength. Based on the manufacturability of the split collet articulations, various forms of articulations are considered by the method of iteration from the traditional rectangular to the idealistic semicircular. The configuration of the articulation shape, the chamfer angle that bevels a right angle in a traditional design, and the chamfer size varied. As a result of calculations, the maximum stresses and displacement of the ends of the articulation, which provides its compression were determined. This compression allows increasing the base diameter of the collet when loading, and the stresses ensure the strength of the collet. Two rational forms of collet articulation that have practical interest are defined. The first form, which is the easiest to manufacture, has a 45° chamfer and, with equal strength, provides almost 15 % more compression of the collet than for a traditional design. The second form, which is more difficult to manufacture, has chamfers of 30° and 60° and with equal strength provides 30 % more compression of the collet.

DETERMINATION OF MECHANISMS OF WEAR FOR ROLLING-SLIDING CONTACT IN SELECTED OPERATIONAL CONDITIONS BY MEANS OF SURFACE TOPOGRAPHY AND MES STUDIES

Tribologia ◽  
2018 ◽  
Vol 273 (3) ◽  
pp. 5-11
Author(s):  
Henryk BĄKOWSKI ◽  
Bogusław ŁAZARZ
Keyword(s):  
Surface Layer ◽  
Operating Conditions ◽  
Simulation Studies ◽  
The Finite Element Method ◽  
Operational Conditions ◽  
Roll To Roll ◽  
Roll System ◽  
Variable Operating Conditions ◽  
Maximum Stresses

The paper presents the influence of selected operating factors, i.e. load, slip, and wear rate, and surface conditions. The wear mechanism between the cooperating rolling surfaces in the rolling/sliding combination varies due to the interaction of the complex stresses / deformations caused by the variable operating conditions. Surface roughness studies have allowed determining the stereological parameters that are specific to the set type of wear. In addition, simulation studies using the Finite Element Method in a roll-to-roll system have been used to determine the value and depth of maximum stresses and deformations occurring in the surface layer due to the interaction of two co-operating bodies. Geometric models have the same properties and disadvantages as the surface layer in a real object. Reflecting the operating conditions and defining the wear mechanisms in the proposed research allowed us to determine the state of the surface layer and predict its durability.

Finite Element Determination of Beam Surface Stresses Due to Multiple Delamination

2009 ◽  
Author(s):  
Benjamin Dauda ◽  
S. Olutunde Oyadiji ◽  
Prassad Potluri
Keyword(s):  
Finite Element ◽  
Spatial Distributions ◽  
Distribution Characteristics ◽  
The Finite Element Method ◽  
Element Determination ◽  
Fixed Length ◽  
Beam Surface ◽  
Multiple Delamination ◽  
Maximum Stresses

The finite element method is used to analyse the through-the-width stress distribution characteristics of single and multiple delaminated cantilevered composite beams. Single delaminations of fixed length, which are located at different through-the-thickness locations, and multiple delaminations of sequential and diagonal configurations are investigated. The total length of multiple delaminations in a beam was made equal to the fixed length of a single delamination. The results show that the configurations and spatial distributions of multiple delaminations have significant effects on the magnitude of the maximum stresses induced in the beams. Beams in which most of the delaminations are concentrated around the mid-plane of the beam show higher stresses than beams in which most of the delaminations are concentrated close to the surface of the laminate. However, delaminations close to the surfaces of the beams exhibit higher stresses at the tips of the delaminations.

EVALUATION OF PARAMETERS DETERMINING PROCESS CAPABILITIES OF MANDRELS WITH SPLIT COLLETS

2020 ◽  
pp. 18-26 ◽  
Author(s):  
D. S. Blinov ◽  
P. V. Klakotsky
Keyword(s):  
The Finite Element Method ◽  
Inexpensive Method ◽  
Method Of Calculation ◽  
Wide Range ◽  
Conical Section ◽  
Evaluation Of Parameters ◽  
Strain Stress ◽  
Thin Walled ◽  
Definition Of

In order to fasten blanks such as rings, bushings, cups and shells, especially thin-walled ones, the use is made of a great number of devices. The previous article contained the review of the devices used and the definition of their structure with split collets, which are highly precise and wide-range, i.e. the most preferable. The devices with split collets are selected as a study object and the task was set to expand a range of diameters of blanks fixed in them while maintaining the collet strength. Developed in this article is a deformation mechanism of the split collet at its unclamping by the shaft conical section. The developed mechanism, with account of the results from the earlier performed studies on determination of the split collet strain-stress behavior, was taken as a basis for the approximated method of calculation the devices with split collets. With the use of the mentioned calculation the analysis was made of the split collet parameters which make it possible to expand a range of diameters of blanks being fixed while maintaining the collet strength. Shape and sizes of a collet belong to such parameters. While considering the variants of the coupling external profile it is necessary to be guided by the process capabilities of a simple and inexpensive method of the mentioned profile manufacture. In order to evaluate the influence of different variants of the coupling external profile shape on process capabilities of the device it is necessary to carry out the comparative calculations by the finite element method. The obtained results of the comparative calculations and their analysis are supposed to be published in the next article.

DINAMIKA POLITIK PERSETUJUAN BERSAMA TENTANG PENETAPAN DESA ADAT DI KABUPATEN ROKAN HULU TAHUN 2014

2017 ◽  
Vol 15 (1) ◽  
pp. 21
Author(s):  
Haryo Suganda ◽  
Raja Muhammad Amin
Keyword(s):  
Regulatory Region ◽  
Field Research ◽  
Analysis Techniques ◽  
Political Dynamics ◽  
Political Interests ◽  
Wide Range ◽  
Information Method ◽  
Qualitative Descriptive ◽  
The Village

This study is motivated the identification of policies issued by the regional Governmentof Rokan Hulu in the form of Regulatory region number 1 by 2015 on the determination of thevillage and Indigenous Village. Political dynamics based on various interests against themanufacture of, and decision-making in the process of formation of the corresponding localregulations determination of Indigenous Villages in the Rokan Hulu is impacted to a verysignificantamount of changes from the initial draft of the number i.e. 21 (twenty one) the villagebecame Customary 89 (eighty-nine) the Indigenous Villages who have passed. Type of thisresearch is a qualitative descriptive data analysis techniques. The research aims to describe theState of the real situation in a systematic and accurate fact analysis unit or related research, aswell as observations of the field based on the data (information). Method of data collectionwas done with interviews, documentation, and observations through fieldwork (field research).The results of the research on the process of discussion of the draft local regulations andmutual agreement about Designation of Indigenous Villages in the Rokan Hulu is, showed thatthe political dynamics that occur due to the presence of various political interests, rejectionorally by Villagers who were judged to have met the requirements of Draft Regulations to beformulated and the area for the set to be Indigenous Villages, and also there is a desire fromsome villages in the yet to Draft local regulations in order to set the Indigenous village , there isa wide range of interests of these aspects influenced the agreement to assign the entire localVillage which is in the Rokan Hulu become Indigenous village, and the village of Transmigrationinto administrative Villages where the initiator of the changes in the number of IndigenousVillages in the Rokan Hulu it is the desire of the local Government of its own.

scholarly journals Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

2021 ◽  
Vol 18 (4) ◽  
pp. 1768
Author(s):  
Hernâni Marques ◽  
Pedro Cruz-Vicente ◽  
Tiago Rosado ◽  
Mário Barroso ◽  
Luís A. Passarinha ◽  
...  
Keyword(s):  
Tobacco Smoke ◽  
Solid Phase ◽  
Smoke Exposure ◽  
Tobacco Smoke Exposure ◽  
World Health ◽  
Second Hand Smoke ◽  
Tobacco Exposure ◽  
Wide Range ◽  
Recent Developments

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid–liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

scholarly journals Determination of Transverse Shear Stiffness of Sandwich Panels with a Corrugated Core by Numerical Homogenization

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1976
Author(s):  
Tomasz Garbowski ◽  
Tomasz Gajewski
Keyword(s):  
Transverse Shear ◽  
Shear Stiffness ◽  
The Finite Element Method ◽  
Homogenization Procedure ◽  
Plate Structures ◽  
Corrugated Board ◽  
Energy Equivalence ◽  
The Stability ◽  
Global Stiffness Matrix

Knowing the material properties of individual layers of the corrugated plate structures and the geometry of its cross-section, the effective material parameters of the equivalent plate can be calculated. This can be problematic, especially if the transverse shear stiffness is also necessary for the correct description of the equivalent plate performance. In this work, the method proposed by Biancolini is extended to include the possibility of determining, apart from the tensile and flexural stiffnesses, also the transverse shear stiffness of the homogenized corrugated board. The method is based on the strain energy equivalence between the full numerical 3D model of the corrugated board and its Reissner-Mindlin flat plate representation. Shell finite elements were used in this study to accurately reflect the geometry of the corrugated board. In the method presented here, the finite element method is only used to compose the initial global stiffness matrix, which is then condensed and directly used in the homogenization procedure. The stability of the proposed method was tested for different variants of the selected representative volume elements. The obtained results are consistent with other technique already presented in the literature.

scholarly journals Applicability of Cork as Novel Modifiers to Develop Electrochemical Sensor for Caffeine Determination

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Mayra K. S. Monteiro ◽  
Djalma R. Da Silva ◽  
Marco A. Quiroz ◽  
Vítor J. P. Vilar ◽  
Carlos A. Martínez-Huitle ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Linear Response ◽  
High Performance ◽  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Caffeine Concentration ◽  
Real Samples ◽  
Wide Range ◽  
Potential Use

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 °C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5–1000 µM), with R2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.

scholarly journals Differential Laboratory Diagnosis of Acute Fever in Guinea: Preparedness for the Threat of Hemorrhagic Fevers

2021 ◽  
Vol 18 (11) ◽  
pp. 6022
Author(s):  
Vladimir G. Dedkov ◽  
N’Faly Magassouba ◽  
Olga A. Stukolova ◽  
Victoria A. Savina ◽  
Jakob Camara ◽  
...  
Keyword(s):  
Ebola Virus ◽  
Febrile Illness ◽  
Laboratory Diagnosis ◽  
Acute Febrile Illness ◽  
Causative Pathogen ◽  
Hemorrhagic Fevers ◽  
Wide Range ◽  
Causative Agents ◽  
Pathognomonic Sign

Acute febrile illnesses occur frequently in Guinea. Acute fever itself is not a unique, hallmark indication (pathognomonic sign) of any one illness or disease. In the infectious disease context, fever’s underlying cause can be a wide range of viral or bacterial pathogens, including the Ebola virus. In this study, molecular and serological methods were used to analyze samples from patients hospitalized with acute febrile illness in various regions of Guinea. This analysis was undertaken with the goal of accomplishing differential diagnosis (determination of causative pathogen) in such cases. As a result, a number of pathogens, both viral and bacterial, were identified in Guinea as causative agents behind acute febrile illness. In approximately 60% of the studied samples, however, a definitive determination could not be made.

scholarly journals Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 80
Author(s):  
Dmitry V. Vedernikov ◽  
Alexander N. Shanygin ◽  
Yury S. Mirgorodsky ◽  
Mikhail D. Levchenkov
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Performance ◽  
Strength Analysis ◽  
Labor Input ◽  
Aerodynamic Loading ◽  
Aspect Ratios ◽  
Wide Range ◽  
Parametrical Design

This publication presents the results of complex parametrical strength investigations of typical wings for regional aircrafts obtained by means of the new version of the four-level algorithm (FLA) with the modified module responsible for the analysis of aerodynamic loading. This version of FLA, as well as a base one, is focused on significant decreasing time and labor input of a complex strength analysis of airframes by using simultaneously different principles of decomposition. The base version includes four-level decomposition of airframe and decomposition of strength tasks. The new one realizes additional decomposition of alternative variants of load cases during the process of determination of critical load cases. Such an algorithm is very suitable for strength analysis and designing airframes of regional aircrafts having a wide range of aerodynamic concepts. Results of validation of the new version of FLA for a high-aspect-ratio wing obtained in this work confirmed high performance of the algorithm in decreasing time and labor input of strength analysis of airframes at the preliminary stages of designing. During parametrical design investigation, some interesting results for strut-braced wings having high aspect ratios were obtained.

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