Djamel Boutagouga and Said Mamouri
This paper aims to investigate post-buckling responses of shell-like structures using an implicit conservative-decaying time integration dynamic scheme.
Abstract
Purpose
This paper aims to investigate post-buckling responses of shell-like structures using an implicit conservative-decaying time integration dynamic scheme.
Design/methodology/approach
In this work, the authors have proposed the use of a four-node quadrilateral flat shell finite element with drilling rotational degree of freedom within the framework of an updated Lagrangian formulation mutually with an implicit conservative-dissipative time integration dynamic scheme.
Findings
Several numerical simulations were considered to evaluate the accuracy, robustness, stability and the capacity of the considered time integration scheme to dissipate numerical noise in the presence of high frequencies. The obtained results illustrate a very satisfying performance of the implicit conservative-dissipative direct time integration scheme conjointly with the quadrilateral flat shell finite element with drilling rotation.
Originality/value
The authors have investigated the potential of the implicit dynamic scheme to deal with unstable branches after limit points in the non-linear post-buckling response of shell structures with no need for structural damping. The capability of the studied algorithm to study buckling and post-buckling behaviour of thin shell structures is illustrated through several numerical examples.
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Keywords
Boštjan Brank, Said Mamouri and Adnan Ibrahimbegović
Aims to address the issues pertaining to dynamics of constrained finite rotations as a follow‐up from previous considerations in statics.
Abstract
Purpose
Aims to address the issues pertaining to dynamics of constrained finite rotations as a follow‐up from previous considerations in statics.
Design/methodology/approach
A conceptual approach is taken.
Findings
In this work the corresponding version of the Newmark time‐stepping schemes for the dynamics of smooth shells employing constrained finite rotations is developed. Different possibilities to choose the constrained rotation parameters are discussed, with the special attention given to the preferred choice of the incremental rotation vector.
Originality/value
The pertinent details of consistent linearization, rotation updates and illustrative numerical simulations are supplied.
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Sedki Karoui and Romdhane Khemakhem
This study aims to better understand the Islamic consumption incentives because the spectacular flourishing of the halal market in different places around the world has grown the…
Abstract
Purpose
This study aims to better understand the Islamic consumption incentives because the spectacular flourishing of the halal market in different places around the world has grown the interest in understanding and deciphering the mechanisms behind its development.
Design/methodology/approach
Through an exploratory study of some Tunisia-based Islamic groups’ purchasing behavior, this paper investigates factors leading to the purchasing of halal goods (Islamic consumption).
Findings
Findings show that the Islamic consumer is more of an Islamist than simply a Muslim. In addition, findings show that halal consumption is not merely related to religious affiliations but also the product of numerous cultural, social and psychological factors.
Originality/value
In addition to Islamism and Islamic activism, this paper puts in evidence the role of some post-structural factors such as identity, nostalgia and hedonism in relation to the buying intention of halal products and services.
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Adnan Ibrahimbegovic, Guillaume Hervé and Pierre Villon
The purpose of this paper is to provide the methodology for structural design of complex massive structures under impact by a large airplane.
Abstract
Purpose
The purpose of this paper is to provide the methodology for structural design of complex massive structures under impact by a large airplane.
Design/methodology/approach
Using case studies, the issues related to multi‐scale modelling of inelastic damage mechanisms for massive structures are discussed, as well as the issues pertaining to the time integration schemes in presence of different scales in time variation of different sub‐problems, brought by a particular nature of loading with a very short duration) and finally the issues related to model reduction seeking to provide an efficient and yet sufficiently reliable basis for parametric studies which are an indispensable part of a design procedure.
Findings
Several numerical simulations are presented in order to further illustrate the approaches proposed herein. Concluding remarks are stated regarding the current and future research in this domain.
Originality/value
Proposed design procedure for complex massive engineering structures under impact by a large airplane provides on one side a very reliable representation of inelastic damage mechanisms and external loading represented by the solution of the corresponding contact/impact problem, and on the other side a very efficient basis obtained by model reduction for performing the parametric design studies.
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The purpose of this paper is to investigate internal forces in bridges induced by moving vehicles and compare them to earthquake loading.
Abstract
Purpose
The purpose of this paper is to investigate internal forces in bridges induced by moving vehicles and compare them to earthquake loading.
Design/methodology/approach
Dynamic analysis of bridges is performed for moving support actions, for spectral method with Eurocode 8 parameters and for moving vehicle influence. Results from all three methods have been compared on two examples and conclusions have been made. Moving vehicle analysis could be based on the moving force and on the moving mass approach where the later one requires rather accurate knowledge of structural accelerations. It has been shown that the classical Newmark formulation produces accelerations of low accuracy and a novel impulse acceleration method has been devised.
Findings
It is found that the actions induced by the moving load could be comparable or larger than those caused by the earthquake on bridges whose mass is not too large in comparison to the vehicle mass.
Research limitations/implications
The developed method will be applied to a broader choice of examples and more reliable conclusions made.
Practical implications
There are bridges where it would be appropriate to perform moving vehicle dynamic analysis, in which case the vertical earthquake actions could be neglected in the analysis.
Originality/value
In order to assess actions from moving vehicles, Newmark method has been generalized in a novel way. Paper describes vector formulation of Newmark method that permits free mixing of integration parameters that could vary from node to node. The method is advantageous for moving load analysis where loading conditions of nodes change in time.
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Ab Kasaeian, Reza Daneshazarian, Fathollah Pourfayaz, Sahar Babaei, Mojgan Sheikhpour and Shima Nakhjavani
Because of its increased absorptance in fluid and reduced heat loss, direct absorption nanofluid (DANF) is receiving intense interest as an efficient way to harvest solar energy…
Abstract
Purpose
Because of its increased absorptance in fluid and reduced heat loss, direct absorption nanofluid (DANF) is receiving intense interest as an efficient way to harvest solar energy. This work aims to investigate, for the first time, the application of DANF in parabolic trough collectors (PTC), a promising collector for solar thermal systems.
Design/methodology/approach
A representative flow and heat transfer study of different fluids in a straight tube is conducted, and the basic energy equation and radiative transfer equations are numerically solved to obtain the fluid temperature distribution and energy conversion efficiency. Ethylene glycol (EG) and different concentrations of (i.e., 0.1-0.6 per cent) multi-wall carbon nanotubes (MWCNT) in EG are used as sample fluids. Four cases are studied for a traditional PTC (i.e., using metal tube) and a direct absorption PTC (i.e., using transparent tube) including a bare tube, a tube with an air-filled glass envelope and a tube with vacuumed glass envelop. The numerical results are verified by an experimental study using a copper-glass absorber tube, which reveals the good potential of DANFs.
Findings
Compared with a conventional PTC, using DANF shows an increase of 8.6 per cent and 6.5 K, respectively, in thermal efficiency and outlet temperature difference at a volume fraction (0.5 per cent) of nanoparticles. The results also show that the improvement in solar efficiency increases with increasing particle concentrations, and the vacuum insulated case has the highest efficiency.
Originality/value
In all previous studies, an important section was missing as the effect of photons on the direct solar absorption trough collector, which is considered in this study. This paper proposes a new concept of using direct solar absorption nanofluids for concentrated solar collectors and analyzes the performance of both absorptance and transmittance efficiency considerations. To reveal the potential of the new concept, an analytical model based on energy balance is developed, and two case studies are performed.