scholarly journals Experimental and Numerical Study of Octagonal Composite Column Subject to Various Loading

2017 ◽  
Author(s):  
Mehdi Ebadi Jamkhaneh ◽  
Mohammad Ali Kafi
Keyword(s):  
Numerical Study ◽  
Slenderness Ratio ◽  
Compressive Loading ◽  
Axial Loading ◽  
Experimental Tests ◽  
Composite Column ◽  
Concrete Confinement ◽  
Steel Column ◽  
Different Types ◽  
The Relationship

In this study, experimental tests of the behaviour of steel and partially encased composite (PEC) columns subjected to compressive loading is performed. Evaluation of this type of composite column under axial loading and numerical analysis of its behaviour under combined torsional and axial loading are the main objectives of this study. At first, a parametric study of PEC columns under axial loading was performed in order to find the relationship between flange slenderness ratio of steel column section and concrete confinement. Width-to-thickness ratio of the flange, diameter and spacing of the transverse links were considered as variables in this study. It was observed that dimension of transverse links had almost no effect on the capacity of the specimens, however smaller transverse links spacing increased both capacity and deformability of the specimens. The comparison of the code equations given in CSA S16-14 and EN 1994-1-1 revealed that the equation in CSA S16-14 underestimates the capacity. Furthermore, different types of retrofit of cross-shaped steel column including concrete encasement, use of stiffener plates and transverse links were investigated in this research. Results revealed that concrete confinement and use of transverse links had respectively the most and the least effect on increasing torsional capacity of the specimens.

scholarly journals Experimental and Numerical Investigation of Octagonal Partially Encased Composite Columns Subject to Axial and Torsion Moment Loading

2017 ◽  
Vol 3 (10) ◽  
pp. 939 ◽  
Author(s):  
Mehdi Ebadi Jamkhaneh ◽  
Mohammad Ali Kafi
Keyword(s):  
Numerical Study ◽  
Compressive Loading ◽  
Compressive Load ◽  
Thickness Ratio ◽  
Composite Columns ◽  
Deformation Curves ◽  
Concrete Confinement ◽  
Different Types ◽  
Analytical Phase ◽  
Partially Encased Composite Columns

This paper includes experimental and numerical study of the octagonal partially encased composite (PEC) columns specimens under axial and torsion loading. The major difference between them was the concrete reinforcement details. The parameters investigated in the experimental and numerical study were the type of reinforcement details, the failure mode, width-to-thickness ratio of flange, transverse links spacing and diameter. The results were presented as load-deformation curves. Numerical model was validated using finite element method and the results indicated acceptable accuracy with tests results in the form of capacity and ductility. In the analytical phase, the experimental results in the compressive loading were compared with those obtained from CSA S16-14 and EN 1994-1-1 equations. Also, the new concrete confinement factor in proportion to the web width to thickness ratio was presented to octagonal PEC columns under pure compressive load. Furthermore, different types of retrofit of cross-shaped steel column including concrete encasement, use of stiffener plates and transverse links were investigated in this research. Results revealed that concrete confinement and use of transverse links had respectively the most and the least effect on increasing torsional capacity of the specimens.

Effect of Slenderness Ratio on Inelastic Buckling and Residual Strength of H-Section Steel Column Member

2013 ◽  
Vol 405-408 ◽  
pp. 895-899 ◽  
Author(s):  
Daniel Yeshewawork Abebe ◽  
Jin Woo Kim ◽  
Jeong Hyun Jang ◽  
Jae Hyouk Choi
Keyword(s):  
Total Energy ◽  
Residual Strength ◽  
Slenderness Ratio ◽  
Energy Curve ◽  
Cumulative Energy ◽  
Element Analysis ◽  
Inelastic Buckling ◽  
Steel Column ◽  
Load Displacement ◽  
The Relationship

This study presents the effect of slenderness ratio on inelastic buckling behavior and residual strength of H-section steel column member under axial compression loading. Both end pinned H-section steel column constraining rotation on the weak and strong axis was studied. When column members subjected to unexpected compression load (other than design load) will buckle if the applied load exceeds the critical load that induces buckling. To evaluate the effect of slenderness ratio and the influence of constraining rotation in different axis on the structural behavior of H-section steel column member, explicit nonlinear FEM analysis were carried out with reasonable accuracy. To verify the nonlinear finite element analysis, compression test was conducted and both inelastic deformation and the relationship between load-displacement curves were compared. The cumulative energy curve calculated from the load-displacement relationship curve has also been compared and satisfactory result was obtained. From the analysis result the part total energy (the total energy absorbed by the flanges and web) for the two constrain conditions was presented. Furthermore, based on the deflection theory, the relationship between load and displacement was also proposed.

scholarly journals On the Development of a Release Mechanism for a Split Hopkinson Tension and Compression Bar

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7609
Author(s):  
Georg Baumann ◽  
Dominik Niederkofler ◽  
Christian Ellersdorfer ◽  
Florian Feist
Keyword(s):  
Numerical Study ◽  
Compressive Loading ◽  
High Strength ◽  
Experimental Tests ◽  
Release Mechanism ◽  
Mechanical Characterisation ◽  
Ultra High Strength Steel ◽  
Tension And Compression ◽  
Split Hopkinson ◽  
Rising Time

Split Hopkinson bars are used for the dynamic mechanical characterisation of materials under high strain rates. Many of these test benches are designed in such a way that they can either be used for compressive or tensile loading. The goal of the present work is to develop a release mechanism for an elastically pre-stressed Split Hopkinson bar that can be universally used for tensile or compressive loading. The paper describes the design and dimensioning of the release mechanism, including the brittle failing wear parts from ultra-high strength steel. Additionally, a numerical study on the effect of the time-to-full-release on the pulse-shape and pulse-rising time was conducted. The results of the analytical dimensioning approaches for the release mechanism, including the wear parts, were validated against experimental tests. It can be demonstrated that the designed release concept leads to sufficiently short and reproducible pulse rising times of roughly 0.11 ms to 0.21 ms, depending on the pre-loading level for both the tension and compression wave. According to literature, the usual pulse rising times can range from 0.01 ms to 0.35 ms, which leads to the conclusion that a good average pulse rising time was achieved with the present release system.

Experimental Investigation of the Bullet-proof Properties of Different Kevlar, Comparing .22 Inch with 9 mm Projectiles

2020 ◽  
Vol 13 (1) ◽  
pp. 26-38
Author(s):  
Riaan Stopforth ◽  
Sarp Adali
Keyword(s):  
High Speed ◽  
Experimental Tests ◽  
Test Environment ◽  
Number Of Layers ◽  
Study Results ◽  
Different Types ◽  
Target Set ◽  
Set Up ◽  
The Relationship ◽  
Penetration Depths

Background: Results of an experimental study are given involving high-impact ballistic tests using .22 inch diameter ammunition (commonly known only as .22 ammunition) with the target set up as a combination of different numbers and weights of Kevlar layers. These experimental tests are conducted as literature indicating that the .22 projectiles are not as effective as with larger calibre ammunition. Present work is part of a research study to assess the safety limits of Kevlar layers of different weights against various calibre projectiles. Objective: The objective is to obtain test data to determine the number of Kevlar layers and weights needed for the design of safe bullet proof vests capable of stopping various size ammunition. In the present study, results are given for .22 inch ammunition, which provide data on the characteristics of high-speed ballistic penetration of .22 bullets into Kevlar layers and stopping distances in gel/Kevlar combinations. Methods: Tests were performed with Kevlar fabrics of different weights of Gram per Square Meter (GSM) to provide a comparison among different Kevlar fabrics as well as with different number of Kevlar layers. The tests were conducted with the use of a chronograph in a controlled test environment. The penetration depth in ballistic gelatine was recorded. Results: The results identify the number of layers of Kevlar required to stop a .22 projectile and the relationship between the different layers and weights of Kevlar materials. The results of the .22 projectile penetration are compared with those of different 9 mm Parabellum projectiles to assess the effect of different size ammunition on the bullet-proof capabilities of Kevlar. Experimental data on the penetration depths of different types of bullets into the gel/Kevlar combinations are presented using various graphs. Conclusion: The .22 projectiles perform similar penetration depths compared to that of 9 mm projectiles, and therefore cannot be considered as ineffective ammunition as literature has indicated.

scholarly journals Comparison of VOC Emissions Produced by Different Types of Adhesives Based on Test Chambers

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1924
Author(s):  
Mateusz Kozicki ◽  
Katarzyna Guzik
Keyword(s):  
Indoor Air ◽  
Building Materials ◽  
Indoor Air Pollution ◽  
Experimental Tests ◽  
Upper Respiratory Tract ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Different Types ◽  
Upper Respiratory ◽  
The Relationship

Volatile organic compounds (VOCs) emitted from building materials into the indoor air may cause discomfort associated with a perceptible chemical odour and may irritate the upper respiratory tract. Hence, it is vital to control indoor air pollution sources, such as interior finishing materials, including adhesives. The study involved carrying out a series of experimental tests of VOC emissions of 25 adhesives based on the ISO 16000 series standards. The research concerns three groups of construction adhesives with indoor applications, i.e., flooring (10), finishing walls and ceilings (6), and for other applications such as edge-gluing or gluing tiles or mirrors (9) differing in chemical composition. A series of temperature tests were carried out for a representative floor adhesive at selected temperatures: 25 °C, 35 °C and 45 °C. The theoretical correlation approach was adopted to characterise the relationship between the emission rate and temperature of selected chemical compounds.

scholarly journals DEM-FDM Coupled Numerical Study on the Reinforcement of Biaxial and Triaxial Geogrid Using Pullout Test

2021 ◽  
Vol 11 (19) ◽  
pp. 9001
Author(s):  
Jianjun Fu ◽  
Junfeng Li ◽  
Cheng Chen ◽  
Rui Rui
Keyword(s):  
Numerical Study ◽  
Interaction Mechanism ◽  
Coupled Model ◽  
Deformation Characteristics ◽  
Pullout Tests ◽  
Different Types ◽  
Simulation Results ◽  
The Relationship ◽  
Similar Deformation ◽  
Better Than

The key to modeling the interlocking of geogrid-reinforced ballast is considering both the continuous deformation characteristics of the geogrid and the discontinuity of the ballast particles. For this purpose, pullout tests using biaxial and triaxial geogrids were simulated using the coupled discrete element method (DEM) and finite difference method (FDM). In this coupled model, two real-shaped geogrid models with square and triangular apertures were established using the solid element in FLAC3D. Meanwhile, simplified shaped clumps were used to represent the ballast using PFC3D. The calibration test simulation showed that the accurately formed geogrid model can reproduce the deformation and strength characteristics of a geogrid. The pullout simulation results show that the DEM-FDM method can well predict the relationship between pullout force and displacement, which is more accurate than the DEM method. For ballast particles of 40 mm in size, both the experiment and simulation results showed that the triaxial geogrid of 75 mm is better than the 65-mm biaxial geogrid . In addition, the DEM-FDM method can study the interaction mechanism between the particles and the geogrid from a microscopic view, and also reveal the similar deformation behavior of the geogrid in the pullout process. Therefore, the DEM-FDM coupled method can not only investigate the interlocking mechanism between the ballast and particles but can also provide a great method for evaluating the performance of different types of geogrids.

THEORY OF LAW AND PHILOSOPHY OF LAW AS THEORETICAL DISCOURSES: SPECIFICS AND RELATIONSHIP

2020 ◽  
pp. 9-17
Author(s):  
Вадим Леонидович Афанасьевский
Keyword(s):  
Scientific Knowledge ◽  
Scientific Theory ◽  
Theoretical Concept ◽  
Philosophy Of Law ◽  
The West ◽  
Scientific Creativity ◽  
Key Characteristics ◽  
Different Types ◽  
Theory Of Law ◽  
The Relationship

В статье анализируется проблема взаимоотношений философии права и научной теории права. Рассматриваемая проблема стала особенно актуальной в российском образовательном пространстве в связи с введением после длительного перерыва в государственный образовательный стандарт магистратуры по юриспруденции учебной дисциплины «Философия права». Автор статьи в качестве базисного принимает тезис, согласно которому философия права, являясь сферой философской мысли, и теория права как область научного социогуманитарного знания представляют собой разные типы теоретического дискурса. Исходя из этого, в статье выстраивается теоретическая концепция, согласно которой задачей философии права как философского типа мышления является конструирование или экспликация онтологических, эпистемологических, аксиологических, феноменологических оснований для формирования и функционирования научных теоретико-правовых и историко-правовых построений. Для реализации поставленной в статье задачи подробно рассматриваются ключевые характеристики как теории философского типа, так и идеалов, норм и характеристик научного знания. Выявленное различие экстраполируется на взаимоотношение теории права как продукта научного творчества и философии права как конструкции, задающей базовые мировоззренческие смыслы. В качестве примера выработанных философией права и государства оснований научных теорий прогресса, государства, морали и права, автор приводит взгляды мыслителей западноевропейской философской классики: Т. Гоббса, Ж.-Ж. Руссо, И. Канта, Г.В.Ф. Гегеля. Именно их философские концепции предопределили образы теоретико- и историко-правовых учений XVIII, XIX, XX и даже начала XXI в. Таким образом, отношение философии права и теории права выстраивается по «вертикали»: от онтологического основания к возведению теоретико-правовых и историко-правовых научных построений. The article analyzes the problem of the relationship between the philosophy of law and the scientific theory of law. The problem under consideration has become especially urgent in the Russian educational space in connection with the introduction of the Philosophy of Law discipline master's degree in law after a long break. The author of the article takes as the basis the thesis that the philosophy of law, being the sphere of philosophical thought, and the theory of law as a field of scientific socio-humanitarian knowledge are different types of theoretical discourse. Based on this, the article builds a theoretical concept according to which the task of the philosophy of law as a philosophical type of thinking is the construction or explication of ontological, epistemological, axiological, phenomenological grounds for the formation and functioning of concrete scientific theoretical and legal and historical and legal constructions. To implement the task posed in the article, the key characteristics of both a theory of a philosophical type and ideals, norms and characteristics of scientific knowledge are examined in detail. The revealed difference is extrapolated to the relationship between the theory of law as a product of scientific creativity and the philosophy of law as a construction that sets basic philosophical meanings. As an example of the foundations of the scientific theories of progress, state, morality and law developed by the philosophy of law and the state, the author gives the views and thinkers of the West European philosophical classics T. Hobbes, J.-J. Russo, I. Kant, G.V.F. Hegel. It was their philosophical concepts that predetermined the images of theoretical and historical-legal doctrines of the XVIII, XIX, XX and even the beginning of the XXI centuries. Thus, the attitude of the philosophy of law and the theory of law is built along the «vertical»: from the ontological foundation to the construction of theoretical and historical and historical legal scientific constructions.

Characteristics of Different Types of Childhood Violence and the Risk of Revictimization

2019 ◽  
Vol 25 (14) ◽  
pp. 1696-1716 ◽  
Author(s):  
Ida Frugaard Stroem ◽  
Helene Flood Aakvaag ◽  
Tore Wentzel-Larsen
Keyword(s):  
Childhood Abuse ◽  
Telephone Survey ◽  
Regression Analyses ◽  
Multiple Forms ◽  
Different Types ◽  
Children And Young Adults ◽  
Childhood Violence ◽  
Forms Of Violence ◽  
The Relationship

This study investigates the relationship between the characteristics of different types of childhood violence and adult victimization using two waves of data from a community telephone survey (T1) and a follow-up survey, including 505 cases and 506 controls, aged 17-35 years (T2). The logistic regression analyses showed that exposure to childhood abuse, regardless of type, was associated with adult victimization. Exposure to multiple types of abuse, victimization both in childhood and in young adulthood, and recency of abuse increased these odds. Our findings emphasize the importance of assessing multiple forms of violence when studying revictimization. Practitioners working with children and young adults should be attentive to the number of victimization types experienced and recent victimization to prevent further abuse.

scholarly journals Endolysosomal Cation Channels and MITF in Melanocytes and Melanoma

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1021
Author(s):  
Carla Abrahamian ◽  
Christian Grimm
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Transcription Factor ◽  
Convincing Evidence ◽  
Signaling Cascades ◽  
Cation Channels ◽  
Pore Channel ◽  
Different Types ◽  
Canonical Wnt ◽  
The Relationship

Microphthalmia-associated transcription factor (MITF) is the principal transcription factor regulating pivotal processes in melanoma cell development, growth, survival, proliferation, differentiation and invasion. In recent years, convincing evidence has been provided attesting key roles of endolysosomal cation channels, specifically TPCs and TRPMLs, in cancer, including breast cancer, glioblastoma, bladder cancer, hepatocellular carcinoma and melanoma. In this review, we provide a gene expression profile of these channels in different types of cancers and decipher their roles, in particular the roles of two-pore channel 2 (TPC2) and TRPML1 in melanocytes and melanoma. We specifically discuss the signaling cascades regulating MITF and the relationship between endolysosomal cation channels, MAPK, canonical Wnt/GSK3 pathways and MITF.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

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