Bending tests for the structural safety assessment of space truss members

2018 ◽  
Vol 33 (3-4) ◽  
pp. 138-149 ◽  
Author(s):  
Marco Bonopera ◽  
Kuo-Chun Chang ◽  
Chun-Chung Chen ◽  
Tzu-Kang Lin ◽  
Nerio Tullini
Keyword(s):  
Cross Sections ◽  
Flexural Rigidity ◽  
Compressive Force ◽  
Scale Space ◽  
Transverse Load ◽  
Structural Safety ◽  
Small Scale ◽  
Order Effects ◽  
Beam Columns ◽  
Space Truss

This article compares two nondestructive static methods used for the axial load assessment in prismatic beam-columns of space trusses. Examples include the struts and ties or the tension chords and diagonal braces of steel pipe racks or roof trusses. The first method requires knowledge of the beam-column’s flexural rigidity under investigation, whereas the second requires knowledge of the corresponding Euler buckling load. In both procedures, short-term flexural displacements must be measured at the given cross sections along the beam-column under examination and subjected to an additional transverse load. The proposed methods were verified by numerical and laboratory tests on beams of a small-scale space truss prototype made from aluminum alloy and rigid connections. In general, if the higher second-order effects are induced during testing and the corresponding total displacements are accurately measured, it would be easy to obtain tensile and compressive force estimations.

Compressive Column Load Identification in Steel Space Frames Using Second-Order Deflection-Based Methods

2018 ◽  
Vol 18 (07) ◽  
pp. 1850092 ◽  
Author(s):  
Marco Bonopera ◽  
Kuo-Chun Chang ◽  
Chun-Chung Chen ◽  
Tzu-Kang Lin ◽  
Nerio Tullini
Keyword(s):  
Cross Sections ◽  
Flexural Rigidity ◽  
Scale Space ◽  
Second Order ◽  
Transverse Load ◽  
Small Scale ◽  
Order Effects ◽  
Space Frames ◽  
Compressive Loads ◽  
Steel Space Frames

This paper presents a comparison of two static nondestructive methods used to assess compressive loads in columns of steel space frames. The first method requires knowledge of the flexural rigidity of the column under investigation, whereas the second method requires knowledge of the column’s buckling load. In each method, short-term displacements are measured at given cross-sections along the member under examination, which is subjected to an additional transverse load. The two methods were verified in this study through experimental and numerical tests on a column of a small-scale space frame prototype with generic connections and end conditions. Estimations of compressive forces were generally reliable when second-order effects were accurately considered. In conclusion, the two methods can be successfully used to test steel space frames in a laboratory or under real conditions.

scholarly journals PROBABILITY‐BASED DESIGN OF SPUN CONCRETE BEAM‐COLUMNS

2010 ◽  
Vol 16 (4) ◽  
pp. 451-461 ◽  
Author(s):  
Antanas Kudzys ◽  
Romualdas Kliukas
Keyword(s):  
Cross Sections ◽  
Safety Margin ◽  
High Strength ◽  
Order Effects ◽  
Braced Frames ◽  
Building Frames ◽  
Beam Columns ◽  
Index Approach ◽  
Spun Concrete ◽  
Concrete Beam Columns

The attention of engineers is turned to the application of precast spun concrete columns reinforced by high‐strength steel bars for office and administrative buildings. The paper discusses a possibility of using the reliability index approach to designing beam‐columns of building frames and analyses resistance criteria for beam‐columns of annular cross sections as compression members with bending moments and bending members with compressive forces. First and second order effects of beam‐columns are considered. The article also presents time‐dependent resistance safety margin and its stationary equivalent and investigates the unsophisticated applied models for probability‐based design of frame beam‐columns. The design of a beam‐column of the braced frames is illustrated providing a numerical example. Santrauka Atkreiptas inžinieriu demesys i didžiastiprio plieno strypais armuotu sijiniu kolonu iš centrifuguotojo betono naudojima istaigu ir administraciniuose pastatuose. Aptarta galimybe projektuojant pastato remo sijines kolonas taikyti patikimumo indekso būda. Analizuojamas sijiniu kolonu kaip lenkiamai gniuždomu ir gniuždomai lenkiamu žiedinio skerspjūvio ele‐mentu atspario kriterijus. Nagrinejamos sijiniu kolonu pirmosios ir antrosios eiles iražos. Pateiktas laike kintantis ribines saugos atsparis ir jo stacionarusis ekvivalentas. Tyrinejamas nesudetingas taikomasis modelis remo sijiniu kolonu ti‐kimybiniam projektavimui. Skaitiniu pavyzdžiu iliustruojamas stabilizuojamu remu sijines kolonos projektavimas.

scholarly journals Movement Around Real and Virtual Cluttered Environments

2005 ◽  
Vol 14 (5) ◽  
pp. 580-596 ◽  
Author(s):  
Simon Lessels ◽  
Roy A. Ruddle
Keyword(s):  
Real World ◽  
Search Task ◽  
Scale Space ◽  
Visual Scene ◽  
Field Of View ◽  
Small Scale ◽  
High Fidelity ◽  
Cluttered Environments ◽  
The Real ◽  
Desktop Virtual Environment

Two experiments investigated participants' ability to search for targets in a cluttered small-scale space. The first experiment was conducted in the real world with two field of view conditions (full vs. restricted), and participants found the task trivial to perform in both. The second experiment used the same search task but was conducted in a desktop virtual environment (VE), and investigated two movement interfaces and two visual scene conditions. Participants restricted to forward only movement performed the search task quicker and more efficiently (visiting fewer targets) than those who used an interface that allowed more flexible movement (forward, backward, left, right, and diagonal). Also, participants using a high fidelity visual scene performed the task significantly quicker and more efficiently than those who used a low fidelity scene. The performance differences among all the conditions decreased with practice, but the performance of the best VE group approached that of the real-world participants. These results indicate the importance of using high fidelity scenes in VEs, and suggest that the use of a simple control system is sufficient for maintaining one's spatial orientation during searching.

Fluid Flow and Heat Transfer of Liquid Sodium in Small-Scale Heat Sinks With Different Geometries

2021 ◽  
Author(s):  
Mahyar Pourghasemi ◽  
Nima Fathi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Cross Sections ◽  
Heat Sink ◽  
Volume Ratio ◽  
Heat Sinks ◽  
Liquid Sodium ◽  
Small Scale ◽  
Nusselt Numbers ◽  
The Difference

Abstract 3-D numerical simulations are performed to investigate liquid sodium (Na) flow and the heat transfer within miniature heat sinks with different geometries and hydraulic diameters of less than 5 mm. Two different straight small-scale heat sinks with rectangular and triangular cross-sections are studied in the laminar flow with the Reynolds number up to 1900. The local and average Nusselt numbers are obtained and compared against eachother. At the same surface area to volume ratio, rectangular minichannel heat sink leads to almost 280% higher convective heat transfer rate in comparison with triangular heat sink. It is observed that the difference between thermal efficiencies of rectangular and triangular minichannel heat sinks was independent of flow Reynolds number.

Evaluation of Tensile Properties Profile of Weld Zone Using Instrumented Indentation

2010 ◽  
Author(s):  
Seung-Kyun Kang ◽  
Young-Cheon Kim ◽  
Chan-Pyoung Park ◽  
Dongil Kwon
Keyword(s):  
Tensile Properties ◽  
Weld Zone ◽  
Indentation Test ◽  
Tensile Tests ◽  
Structural Safety ◽  
Small Scale ◽  
Stress And Strain ◽  
Instrumented Indentation ◽  
Deformation And Fracture ◽  
Instrumented Indentation Test

Understanding the property distribution in the weld zone is very important for structural safety, since deformation and fracture begin at the weakest point. However, conventional tensile tests can measure only average material properties because they require large specimens. Small-scale tests are being extensively researched to remove this limitation, among such tests, instrumented indentation test (IIT) are of great interest because of their simple procedures. Here we describe the evaluation of tensile properties using IIT and a representative stress-strain approach. The representative stressstrain method, introduced in 2008 in ISO/TR29381, directly correlates the stress and strain under the indenter to the true stress and strain of tensile testing by defining representative functions. Using this technique, we successfully estimate the yield strength and tensile strength of structural metallic materials and also obtain profiles of the weld-zone tensile properties.

Hydrostatic Collapse Pressure and Radial Collapse Force Comparisons for Ultra-Deepwater Pipelines

2014 ◽  
Author(s):  
Marco A. P. Rosas ◽  
Ana Paula F. Souza ◽  
Marcos V. Rodrigues ◽  
Danilo Machado L. da Silva
Keyword(s):  
Numerical Models ◽  
Research Work ◽  
Compressive Force ◽  
Quadratic Function ◽  
Radial Force ◽  
Small Scale ◽  
Collapse Pressure ◽  
First Results ◽  
Specimen Test ◽  
The Relationship

In this paper the behavior and the relationship between hydrostatic collapse pressure and diametrically opposed radial compressive force for pipelines were analyzed. This study presents an introduction of a research work aimed to assess the pipeline collapse pressure based on the radial collapse force. Initially the hydrostatic collapse pressure is analyzed, for pipes with different diameter to wall thickness ratio (D/t) and ovalities, using classical assessment (DNV method) and numerical models (FE). Then, the compressive radial force is also analyzed using numerical models validated by a small-scale ring specimen test. After that, the relationship between hydrostatic collapse pressure and compressive radial force is discussed. These first results show that the radial force is a quadratic function of the collapse pressure.

Measurement of fission neutron spectrum averaged cross sections of some threshold reactions on europium: small scale production of no-carrier-added 153Sm in a nuclear reactor

2002 ◽  
Vol 90 (2) ◽  
Author(s):  
I. Fatima ◽  
Jamshed H. Zaidi ◽  
Shujaat Ahmad ◽  
M. S. Subhani
Keyword(s):  
Neutron Spectrum ◽  
Cross Sections ◽  
Nuclear Reactor ◽  
Fission Neutron ◽  
Small Scale ◽  
Activation Technique ◽  
Scale Production ◽  
Radiochemical Separations ◽  
Fission Neutron Spectrum ◽  
Γ Ray

SummaryEmploying the activation technique in combination with radiochemical separations and high-resolution γ-ray spectroscopy fission neutron spectrum averaged cross sections were measured for several (

scholarly journals MEASURING DIGITAL DIVIDE IN KING ABDULAZIZ UNIVERSITY

2012 ◽  
Vol 3 (1) ◽  
pp. 8-19
Author(s):  
Iqbal S. Alsaleh ◽  
Shaymaa M. Rashad
Keyword(s):  
Digital Divide ◽  
Information And Communication Technologies ◽  
Communication Technologies ◽  
Information And Communications Technology ◽  
Small Scale ◽  
Order Effects ◽  
Diffusion Of Technology ◽  
Information And Communication ◽  
King Abdulaziz University ◽  
The University

Due to the undesirable effects of the gap between citizens to access and use information and communication technologies (ICT), most researchers have been paying much attention to the threat of a digital divide. Unfortunately an amazingly large number of people do not have the abilities to use the ICTs in a proper way and, therefore, cannot draw advantages from its usage. As a result, digital divide is commonly regarded as a potential barrier for participation in the information society. This study measure the digital divide in Saudi Arabia by analyzing the results of a small-scale study conducted at the University KAU, regarding students’ and university members’ perceptions toward the usage of ICT. This analysis measure the digital divide concerning some factors like gender, educational level using a questionnaire. The analysis shows that KAU has no digital divide. Key words: digital divide, information and communications technology, ICT, diffusion of technology, second order effects.

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