scholarly journals Experimental Investigation of Thin-walled Column-end Joints Encased in Ultra-lightweight Concrete

2017 ◽  
Author(s):  
Péter Hegyi ◽  
László Dunai
Keyword(s):  
Experimental Investigation ◽  
Cross Sections ◽  
Failure Modes ◽  
Lightweight Concrete ◽  
Close Correlation ◽  
Structural Detail ◽  
Structural System ◽  
Compression Members ◽  
Different Types ◽  
Thin Walled

A novel thin-walled structural system is under development which aims to utilise the beneficial effect of continuous bracing achieved by encasing CFS elements in ultra-lightweight-concrete. This paper deals with the experimental analysis of column-end joints. Altogether six types of end connection and four cross-sections were tested by 18 unbraced and 48 braced specimens. Based on the results four main zones of the load-displacement curves were defined which represent the behaviour of the different types. The failure modes and ultimate loads were identified and were found to be in close correlation with the results of previous tests on compression members. The experimental test helped to identify the main parameters of thin-walled column-end joints which affect the behaviour of the structural detail.

scholarly journals Buckling behavior of cold-formed steel columns at both ambient temperature and simulated fire conditions

Fire Research ◽  
2016 ◽  
Author(s):  
Hélder D. Craveiro ◽  
João Paulo C. Rodrigues ◽  
Luís M. Laím
Keyword(s):  
Experimental Investigation ◽  
Ambient Temperature ◽  
Cross Sections ◽  
Failure Modes ◽  
Steel Columns ◽  
Buckling Behavior ◽  
Wide Range ◽  
Cold Formed Steel ◽  
Simulated Fire ◽  
Fire Conditions

Cold-formed steel (CFS) profiles with a wide range of cross-section shapes are commonly used in building construction industry. Nowadays several cross-sections can be built using the available standard single sections (C, U, Σ, etc.), namely open built-up and closed built-up cross-sections. This paper reports an extensive experimental investigation on the behavior of single and built-up cold-formed steel columns at both ambient and simulated fire conditions considering the effect of restraint to thermal elongation. The buckling behavior, ultimate loads and failure modes, of different types of CFS columns at both ambient and simulated fire conditions with restraint to thermal elongation, are presented and compared. Regarding the buckling tests at ambient temperature it was observed that the use of built-up cross-sections ensures significantly higher values of buckling loads. Especially for the built-up cross-sections the failure modes were characterized by the interaction of individual buckling modes, namely flexural about the minor axis, distortional and local buckling. Regarding the fire tests, it is clear that the same levels of restraint used in the experimental investigation induce different rates in the generated restraining forces due to thermal elongation of the columns. Another conclusion that can be drawn from the results is that by increasing the level of restraint to thermal elongation the failure of the columns is controlled by the generated restraining forces, whereas for lower levels of restraint the temperature plays a more important role. Hence, higher levels of imposed restraint to thermal elongation will lead to higher values of generated restraining forces and eventually to lower values of critical temperature and time.

Impact of multi-dimensional vibration trajectories on quality and failure modes in ultrasonic bonding

2019 ◽  
Vol 2019 (1) ◽  
pp. 000509-000514
Author(s):  
Reinhard Schemmel ◽  
Florian Eacock ◽  
Collin Dymel ◽  
Tobias Hemsel ◽  
Matthias Hunstig ◽  
...  
Keyword(s):  
Cross Sections ◽  
Failure Modes ◽  
Copper Substrate ◽  
Industrial Process ◽  
Acoustic Microscopy ◽  
Ultrasonic Power ◽  
Bond Quality ◽  
Ultrasonic Bonding ◽  
Different Types ◽  
Electrical Connections

Abstract Ultrasonic joining is a common industrial process. To build electrical connections in the electronics industry, uni-axial and torsional ultrasonic vibration have been used to join different types of workpieces for decades. Many influencing factors like ultrasonic power, bond normal force, bond duration and frequency are known to have a high impact on bond quality and reliability. Multi-dimensional bonding has been investigated in the past to increase ultrasonic power and consequently bond strength. This contribution is focused on the comparison of circular, multi-frequency planar and uniaxial vibration trajectories used for ultrasonic bonding of copper pins on copper substrate. Bond quality was analyzed by shear tests, scanning acoustic microscopy and interface cross-sections.

Experimental Investigation of Energy Absorption of ‎Partially Wrapped Thin-Walled ‎Aluminium-Glass/Epoxy Tube Subjected to Quasi-Static Loading

2017 ◽  
Vol 904 ◽  
pp. 61-67
Author(s):  
Tahir Abbas ◽  
Hamdan H. Ya ◽  
Mohamad Zaki Abdullah
Keyword(s):  
Experimental Investigation ◽  
Energy Absorption ◽  
Fiber Orientation ◽  
Static Loading ◽  
Failure Modes ◽  
Testing Machine ◽  
Filament Winding ◽  
Universal Testing ◽  
Thin Walled ◽  
Filament Winding Process

This paper describes the failure modes and energy absorption capability of partially wrapped aluminium-glass/epoxy tubes, subjected to quasi-static loading. ‎These tubes are used in aircraft and automobiles applications. Aluminium tubes were partially wrapped with 4, 6 and 8 glass/epoxy layers, using filament winding process. The 90◦ fiber orientation was used for glass/epoxy layers. Quasi-static loading of partially wrapped tubes was carried out at 5mm/min speed, using the universal ‎testing machine. The experimental results revealed that partially wrapped aluminium tubes are 42.54%, 47.77% and 28.91% more ‎efficient in energy absorption as compared to the simple aluminium tubes. Furthermore, the effect of glass/epoxy layers on ‎failure modes has also been described.

Study on Three-Point Bending Mechanical Performance of Thin-Walled Super Alloy Honeycomb Sandwich with Penetrable Defects

2011 ◽  
Vol 314-316 ◽  
pp. 1203-1209
Author(s):  
Kai Yang ◽  
Li Wu Liu ◽  
Kai Ping Yu ◽  
Xiang Hao Kong
Keyword(s):  
Failure Modes ◽  
Mechanical Performance ◽  
Lower Plate ◽  
Three Point Bending ◽  
Fracture Failure ◽  
Bending Load ◽  
Honeycomb Sandwich ◽  
Different Types ◽  
Thin Walled ◽  
Super Alloy

By three-point bending experiments on XY-plane of thin-walled super alloy honeycomb sandwich with different types and dimensions of penetrable defects, their failure modes and influence of defects of different types and dimensions on their mechanical properties are researched by observing failure modes and performance curves of test samples. Researches show that when failure occurs on sandwich structures under three-point loading, vertical to XY-plane, buckling depression occurs on center part of the upper plate along with fracture failure occurring on center part of the lower plate. Similar to three-point experiment on conventional structures, failure always occurs in the longitudinal regions near middle loading area. When lateral walls of honeycomb or strengthen points of welding are set at center loading area, fracture failure occurs on the lower plate, or only buckling deformation occurs on honeycomb cores. And by comparison, FE model can be used to evaluate its mechanical performance of thin-walled super alloy honeycomb sandwich with penetrable defects under three-point bending load. It is the experimental basis for improving the structural reliability and damage tolerance of the structure.

Experimental Investigation of Prestressing in Double-Layer Grids

1994 ◽  
Vol 9 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Robert Levy ◽  
Ariel Hanaor ◽  
Nancy Rizzuto
Keyword(s):  
Experimental Investigation ◽  
Double Layer ◽  
Cross Sections ◽  
Experimental Work ◽  
Peak Load ◽  
Trade Off ◽  
Structural Efficiency ◽  
Compression Members ◽  
Increased Strength ◽  
Full Utilization

Practical designs of double-layer grids often fail to achieve full utilization of the structural efficiency inherent in this spatial framework. This ineffi-ciency is due partly to the tendency to use a small number of different cross-sections, and partly to the sensitivity of compression members with “brittle type” buckling characteristics to imperfections. Prestressing can enhance structural efficiency through recruitment of unutilized member capacity. The procedure also enables improvement of ductility through some controlled strength trade-off. Results of the experimental work presented in this paper indicated increased strength of 40% compared with the non-prestressed configuration as well as enhanced ductility in the peak load region. Larger enhancements are feasible in large grids.

Compressed Thin-Walled Cold-Formed Steel Members with Closed Cross-Sections

2014 ◽  
Vol 969 ◽  
pp. 93-96 ◽  
Author(s):  
Mohamad Al Ali
Keyword(s):  
Experimental Investigation ◽  
Theoretical Analysis ◽  
Cross Sections ◽  
Theoretical Research ◽  
Loading Process ◽  
Steel Members ◽  
Fundamental Information ◽  
Cold Formed Steel ◽  
Thin Walled ◽  
Theoretical Results

The paper presents fundamental information about experimental-theoretical research oriented to determinate the resistance of thin-walled compressed steel members. The investigated members had closed cross-sections made from homogeneous materials. The theoretical analysis in this research is oriented to determinate the resistance of mentioned members according to relevant standards, while the experimental investigation is to verify the theoretical results and to investigate the behavior of mentioned members during the loading process.

Geological Field Sketches and Illustrations

2019 ◽  
Author(s):  
Matthew J. Genge
Keyword(s):  
Cross Sections ◽  
Earth Science ◽  
Three Dimensional ◽  
Worked Examples ◽  
Scientific Publications ◽  
Thin Sections ◽  
Geological Features ◽  
Different Types ◽  
The Subject

Drawings, illustrations, and field sketches play an important role in Earth Science since they are used to record field observations, develop interpretations, and communicate results in reports and scientific publications. Drawing geology in the field furthermore facilitates observation and maximizes the value of fieldwork. Every geologist, whether a student, academic, professional, or amateur enthusiast, will benefit from the ability to draw geological features accurately. This book describes how and what to draw in geology. Essential drawing techniques, together with practical advice in creating high quality diagrams, are described the opening chapters. How to draw different types of geology, including faults, folds, metamorphic rocks, sedimentary rocks, igneous rocks, and fossils, are the subjects of separate chapters, and include descriptions of what are the important features to draw and describe. Different types of sketch, such as drawings of three-dimensional outcrops, landscapes, thin-sections, and hand-specimens of rocks, crystals, and minerals, are discussed. The methods used to create technical diagrams such as geological maps and cross-sections are also covered. Finally, modern techniques in the acquisition and recording of field data, including photogrammetry and aerial surveys, and digital methods of illustration, are the subject of the final chapter of the book. Throughout, worked examples of field sketches and illustrations are provided as well as descriptions of the common mistakes to be avoided.

scholarly journals Experimental investigation and analytical modelling of shear strength of thin walled textile-reinforced UHPC beams

2021 ◽  
Vol 231 ◽  
pp. 111735
Author(s):  
Philipp Preinstorfer ◽  
Patrick Huber ◽  
Tobias Huber ◽  
Benjamin Kromoser ◽  
Johann Kollegger
Keyword(s):  
Experimental Investigation ◽  
Shear Strength ◽  
Analytical Modelling ◽  
Thin Walled
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