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.

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.

Nanofillers’ Effects on Fracture Energy in Composite Aerospace Structures

2019 ◽  
Vol 827 ◽  
pp. 43-48
Author(s):  
Andrea Sellitto ◽  
Aniello Riccio ◽  
A. Russo ◽  
Antonio Garofano ◽  
Mauro Zarrelli
Keyword(s):  
Fracture Toughness ◽  
Composite Materials ◽  
Composite Laminates ◽  
Compressive Loading ◽  
Compressive Load ◽  
Numerical Procedure ◽  
Delamination Growth ◽  
Different Types ◽  
Research Programmes ◽  
Consequent Reduction

Composite materials damage behaviour is, nowadays, extensively investigated in the frame of aerospace research programmes. Among the several failure mechanisms which can affect composites, delamination can be considered as the most critical one, especially when combined to compressive loading conditions. In this context, nanofillers can represent an effective way to increase the composites fracture toughness with a consequent reduction of the delamination onset and evolution. Hence, in this paper, the toughening effect of the nanofillers on the delamination growth in composite material panels, subject to compressive load, has been numerically studied. A validated robust numerical procedure for the prediction of the delamination growth in composite materials panel, named SMXB and based on the VCCT-Fail release approach, has been used to perform numerical analyses by considering two different types of nanofillers. Reference material, without nanofillers insertion, has been used as benchmark in order to assess the capability of nanofillers to enhance the fracture toughness in composite laminates.

Numerical Simulations of Fully Encased Composite Columns under Gravity Loads

2016 ◽  
Vol 860 ◽  
pp. 140-145 ◽  
Author(s):  
Md Soebur Rahman ◽  
Mahbuba Begum
Keyword(s):  
Composite Structures ◽  
Numerical Study ◽  
Concrete Strength ◽  
Fe Model ◽  
Nonlinear Behaviour ◽  
Composite Columns ◽  
Axial Capacity ◽  
Concrete Confinement ◽  
Inelastic Behaviour ◽  
Steel Shapes

Composite structures is a combination of structural steel shapes and reinforced concrete and these two materials are combined in such a way to benefit each material characteristic. This paper investigates the behaviour and strength of axially loaded concrete encased steel composite columns. A nonlinear 3-D finite element (FE) model has been developed to analyse the inelastic behaviour of steel, concrete, and longitudinal reinforcement as well as the effect of concrete confinement on fully encased composite (FEC) columns. The model has been verified against the experiments conducted in the laboratory under concentric gravity loads. It has been found that the FE model is capable of predicting the nonlinear behaviour of the FEC columns up to failure with good accuracy. The capacities of each constituent of FEC columnssuch as steel-I section, concrete and rebars were also determined from the numerical study. Concrete is observed to provide around 57% of the total axial capacity of the column whereas the steel I-sections contributes to the rest of the capacity as well as to the ductility of the overall system. The nonlinear FE model developed in this study is also used to explore the effects of concrete strength on the behaviour of FEC columns under concentric loads. The axial capacity of FEC columns has been found to increase significantly by increasing the strength of concrete.

A Non-Cooperative Game Analysis of Competition between Content Providers in the Internet Market

2019 ◽  
Vol 15 (1) ◽  
pp. 88-104 ◽  
Author(s):  
M'hamed Outanoute ◽  
Hamid Garmani ◽  
Mohamed Baslam ◽  
Rachid El Ayachi ◽  
Belaid Bouikhalene
Keyword(s):  
Quality Of Service ◽  
Detailed Analysis ◽  
Cooperative Game ◽  
Price Of Anarchy ◽  
Numerical Study ◽  
Pure Nash Equilibrium ◽  
Game Analysis ◽  
Different Types ◽  
Internet Market

In internet market, content providers (CPs) continue to play a primordial role in the process of accessing different types of data. Competition in this area is fierce; customers are looking for providers that offer them good content (credibility of content and quality of service) with a reasonable price. In this work, the authors analyze this competition between CPs and the economic influence of their strategies on the market. The authors formulate their problem as a non-cooperative game among multiple CPs for the same market. Through a detailed analysis, the researchers prove uniqueness of a pure Nash Equilibrium (NE). Furthermore, a fully distributed algorithm to converge on the NE point is presented. In order to quantify how efficient the NE point is, a detailed analysis of the Price of Anarchy (PoA) is adopted to ensure the performance of the system at equilibrium. Finally, an extensive numerical study is provided to describe the interactions between CPs and to point out the importance of quality of service (QoS) and credibility of content in the market.

Bejan’s Constructal Theory Analysis of Gas-Liquid Cooled Finned Modules

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Giulio Lorenzini ◽  
Simone Moretti
Keyword(s):  
Thermal Behavior ◽  
Heat Exchangers ◽  
High Performance ◽  
Numerical Study ◽  
Constructal Theory ◽  
Electronic Components ◽  
Theory Analysis ◽  
Pressure Losses ◽  
Different Types ◽  
Overall Performance

High performance heat exchangers represent nowadays the key of success to go on with the trend of miniaturizing electronic components as requested by the industry. This numerical study, based on Bejan’s Constructal theory, analyzes the thermal behavior of heat removing fin modules, comparing their performances when operating with different types of fluids. In particular, the simulations involve air and water (as representative of gases and liquids), to understand the actual benefits of employing a less heat conductive fluid involving smaller pressure losses or vice versa. The analysis parameters typical of a Constructal description (such as conductance or Overall Performance Coefficient) show that significantly improved performances may be achieved when using water, even if an unavoidable increase in pressure losses affects the liquid-refrigerated case. Considering the overall performance: if the parameter called Relevance tends to 0, air prevails; if it tends to 1, water prevails; if its value is about 0.5, water prevails in most of the case studies.

scholarly journals Tissue Modification of the Lateral Compartment of the Tibio-Femoral Joint Following In Vivo Varus Loading in the Rat

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
M. L. Roemhildt ◽  
B. D. Beynnon ◽  
M. Gardner-Morse ◽  
K. Anderson ◽  
G. J. Badger
Keyword(s):  
Articular Cartilage ◽  
Subchondral Bone ◽  
Compressive Loading ◽  
Compressive Load ◽  
Lateral Compartment ◽  
Peripheral Region ◽  
Degenerative Changes ◽  
Medial Compartment ◽  
Compressive Loads

This study describes the first application of a varus loading device (VLD) to the rat hind limb to study the role of sustained altered compressive loading and its relationship to the initiation of degenerative changes to the tibio-femoral joint. The VLD applies decreased compressive load to the lateral compartment and increased compressive load to the medial compartment of the tibio-femoral joint in a controlled manner. Mature rats were randomized into one of three groups: unoperated control, 0% (sham), or 80% body weight (BW). Devices were attached to an animal’s leg to deliver altered loads of 0% and 80% BW to the experimental knee for 12 weeks. Compartment-specific material properties of the tibial cartilage and subchondral bone were determined using indentation tests. Articular cartilage, calcified cartilage, and subchondral bone thicknesses, articular cartilage cellularity, and degeneration score were determined histologically. Joint tissues were sensitive to 12 weeks of decreased compressive loading in the lateral compartment with articular cartilage thickness decreased in the peripheral region, subchondral bone thickness increased, and cellularity of the midline region decreased in the 80% BW group as compared to the 0% BW group. The medial compartment revealed trends for diminished cellularity and aggregate modulus with increased loading. The rat-VLD model provides a new system to evaluate altered quantified levels of chronic in vivo loading without disruption of the joint capsule while maintaining full use of the knee. These results reveal a greater sensitivity of tissue parameters to decreased loading versus increased loading of 80% BW for 12 weeks in the rat. This model will allow future mechanistic studies that focus on the initiation and progression of degenerative changes with increased exposure in both magnitude and time to altered compressive loads.

scholarly journals Multi-configuration Stiffened Panels under Compressive Load: Part 1 – Theoretical Analysis

2018 ◽  
Vol 7 (3.11) ◽  
pp. 38
Author(s):  
Ramzyzan Ramly ◽  
Wahyu Kuntjoro ◽  
Amir Radzi Abdul Ghani ◽  
Rizal Effendy Mohd Nasir ◽  
Zulkifli Muhammad
Keyword(s):  
Theoretical Analysis ◽  
Experimental Analysis ◽  
Critical Loads ◽  
Input Parameter ◽  
Compressive Loading ◽  
Compressive Load ◽  
Cross Sectional ◽  
Stiffened Panels ◽  
Compression Load ◽  
Main Input

Stiffened panels are the structure used in the aircraft wing skin panels. Stiffened panels are often critical in compression load due to its thin structural configuration. This paper analyzes the critical loads of a multi configuration stiffened panels under axial compressive loading. The study comprised three main sections; theoretical analysis, numerical analysis and experimental analysis. The present paper deals only with the theoretical analysis. This first part of analysis is very important since the results will be the main input parameter for the subsequent numerical and experimental analysis. The analysis was done on the buckling properties of the panels. Four panel configurations were investigated. Results showed that even though the stiffened panels have the same cross-sectional area, their critical loads were not identical.   

Uplift behaviour of tapered piles established from model tests

2000 ◽  
Vol 37 (1) ◽  
pp. 56-74 ◽  
Author(s):  
M Hesham El Naggar ◽  
Jin Qi Wei
Keyword(s):  
Load Transfer ◽  
Compressive Loading ◽  
Compressive Load ◽  
Tensile Load ◽  
Confining Pressure ◽  
Cohesionless Soil ◽  
Uplift Capacity ◽  
Experimental Modelling ◽  
Confining Pressures ◽  
Load Tests

Tapered piles have a substantial advantage with regard to their load-carrying capacity in the downward frictional mode. The uplift performance of tapered piles, however, has not been fully understood. This paper describes the results of an experimental investigation into the characteristics of the uplift performance of tapered piles. Three instrumented steel piles with different degrees of taper were installed in cohesionless soil and subjected to compressive and tensile load tests. The soil was contained in a steel soil chamber and pressurized using an air bladder to facilitate modelling the confining pressures pertinent to larger embedment depths. The results of this study indicated that the pile axial uplift capacity increased with an increase in the confining pressure for all piles examined in this study. The ratios of uplift to compressive load for tapered piles were less than those for straight piles of the same length and average embedded diameter. The uplift capacity of tapered piles was found to be comparable to that of straight-sided wall piles at higher confining pressure values, suggesting that the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles. Also, the results indicated that residual stresses developed during the compressive loading phase and their effect were more significant on the initial uplift capacity of piles, and this effect was more pronounced for tapered piles in medium-dense sand.Key words: tapered piles, uplift, axial response, load transfer, experimental modelling.

Sign in / Sign up

Export Citation Format

Share Document