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Article
Publication date: 1 September 1997

A. Hernández, J. Albizuri, M.B.G. Ajuria and M.V. Hormaza

Proposes an automatic adaptive meshing scheme. Error in strain energy is directly obtained through strain energy density function (SED). Versatility of this function, in…

560

Abstract

Proposes an automatic adaptive meshing scheme. Error in strain energy is directly obtained through strain energy density function (SED). Versatility of this function, in comparison with that of others, is looked at in detail. Mesh enrichment method consists of a series of h‐refinement steps and concludes with a single p‐refinement step. Adds that an examination of the accuracy of the element used in the refinement procedure is made. This scheme has been implemented in ZATILAN, a FE code developed in the Department of the Mechanical Engineering of the University of the Basque Country.

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Engineering Computations, vol. 14 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 June 1999

A. Hernández, J. Albizuri, R. Avilés and E. Amezua

The present paper proposes a procedure for the resolution of non‐linear structural problems. It includes a study of the reliability of the results and the adaptive meshing. The…

323

Abstract

The present paper proposes a procedure for the resolution of non‐linear structural problems. It includes a study of the reliability of the results and the adaptive meshing. The iterative phase of the solution of the equilibrium equations entails an adaptive strategy for updating the tangent stiffness matrix, with a control of the load step. This results in a higher rate of convergence for the iterative process. The mechanical deformation processes here considered may give rise to considerable geometric distortion in the finite elements of the mesh. If they do, the consequence will be not only that the FE analysis fails to yield precise results, but also, owing to problems deriving from the numerical ill‐conditioning, that continuation may be impractical. To facilitate the study of these results, we developed an error estimator of the flux projection type, which is based on the mechanical deformation power. It is also used as a refinement criterion for the FE mesh. Distorted meshes can be fully or partially submitted to a process of regularization based on the aspect ratio of their elements. The mesh contour may be affected by the refinement and regularization processes, for which reason we developed a procedure for its updating. This procedure is of more importance in the case of contact problems, its primary object being to avoid interpenetration. The work was done in the ZATILAN code, developed by the Department of Mechanical Engineering of the University of the Basque Country.

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Engineering Computations, vol. 16 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 16 November 2018

Soheil Mohajerani, Duruo Huang, Gang Wang, Seyed-Mohammad Esmaeil Jalali and Seyed Rahman Torabi

This study aims to develop an efficient algorithm for generation of conforming mesh for seepage analysis through 3D discrete fracture networks (DFN).

139

Abstract

Purpose

This study aims to develop an efficient algorithm for generation of conforming mesh for seepage analysis through 3D discrete fracture networks (DFN).

Design/methodology/approach

The algorithm is developed based on a refined conforming Delaunay triangulation scheme, which is then validated using analytical solutions. The algorithm is well able to meet the challenge of meshing complex geometry of DFNs.

Findings

A series of sensitivity analysis have been performed to evaluate the effect of meshing parameters on steady state solution of Darcy flow using a finite element scheme. The results show that an optimized minimum internal angle of meshing elements should be predetermined to guarantee termination of the algorithm.

Originality/value

The developed algorithm is computationally efficient, fast and is of low cost. Furthermore, it never changes the geometrical structure and connectivity pattern of the DFN.

Details

Engineering Computations, vol. 35 no. 8
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 September 2002

Ch. Pinto, R. Avilés, J. Albizuri and A. Hernández

In this second part of the paper, some properties of the discretization error estimators are presented, although their theoretical background was already developed in the first…

197

Abstract

In this second part of the paper, some properties of the discretization error estimators are presented, although their theoretical background was already developed in the first part. Two numerical examples have been selected and will be used to check some properties of these error estimators. In addition to this, some practical conclusions will be addressed from the results and graphical output of the implemented procedure.

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Engineering Computations, vol. 19 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 September 2002

A. Hernández, Ch. Pinto, J. Albizuri and O. Altuzarra

This paper focuses on the study of finite element (FE) analysis reliability of non‐linear planar structural problems (large strains and plasticity). In this first part, some error…

171

Abstract

This paper focuses on the study of finite element (FE) analysis reliability of non‐linear planar structural problems (large strains and plasticity). In this first part, some error estimators of the flux projection type have been developed over the strain power density concept. Spatial, temporal and global error estimators are proposed. From this point, the authors analyse the behaviour of different discretization error components as a function of parameters such as load step or the number of degrees of freedom of the FE model. In the second part of this work, several properties of these estimators are checked with the application to some numerical examples.

Details

Engineering Computations, vol. 19 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 15 March 2022

Mohamed H. Sharaf, Adham M. Nagiub, Salem S. Salem, Mohamed H. Kalaba, Esmail M. El Fakharany and Hamada Abd El-Wahab

This study aims to focus on the preparation and characterization of the silver nanowire (AgNWs), as well as their application as antimicrobial and antivirus activities either with…

310

Abstract

Purpose

This study aims to focus on the preparation and characterization of the silver nanowire (AgNWs), as well as their application as antimicrobial and antivirus activities either with incorporation on the waterborne coating formulation or on their own.

Design/methodology/approach

Prepared AgNWs are characterized by different analytical instruments, such as ultraviolet-visible spectroscope, scanning electron microscope and X-ray diffraction spectrometer. All the paint formulation's physical and mechanical qualities were tested using American Society for Testing and Materials, a worldwide standard test procedure. The biological activities of the prepared AgNWs and the waterborne coating based on AgNWs were investigated. And, their effects on pathogenic bacteria, antioxidants, antiviral activity and cytotoxicity were also investigated.

Findings

The obtained results of the physical and mechanical characteristics of the paint formulation demonstrated the formulations' greatest performance, as well as giving good scrub resistance and film durability. In the antimicrobial activity, the paint did not have any activity against bacterial pathogen, whereas the AgNWs and AgNWs with paint have similar activity against bacterial pathogen with inhibition zone range from 10 to 14 mm. The development of antioxidant and cytotoxicity activity of the paint incorporated with AgNWs were also observed. The cytopathic effects of herpes simplex virus type 1 (HSV-1) were reduced in all three investigated modes of action when compared to the positive control group (HSV-1-infected cells), suggesting that these compounds have promising antiviral activity against a wide range of viruses, including DNA and RNA viruses.

Originality/value

The new waterborne coating based on nanoparticles has the potential to be promising in the manufacturing and development of paints, allowing them to function to prevent the spread of microbial infection, which is exactly what the world requires at this time.

Details

Pigment & Resin Technology, vol. 52 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 2 May 2017

Danguang Pan and Chenfeng Li

Extended from the classic Rayleigh damping model in structural dynamics, the Caughey damping model allows the damping ratios to be specified in multiple modes while satisfying the…

193

Abstract

Purpose

Extended from the classic Rayleigh damping model in structural dynamics, the Caughey damping model allows the damping ratios to be specified in multiple modes while satisfying the orthogonality conditions. Despite these desirable properties, Caughey damping suffers from a few major drawbacks: depending on the frequency distribution of the significant modes, it can be difficult to choose the reference frequencies that ensure reasonable values for all damping ratios corresponding to the significant modes; it cannot ensure all damping ratios are positive. This paper aims to present a constrained quadratic programming approach to address these issues.

Design/methodology/approach

The new method minimizes the error of the structural displacement peak based on the response spectrum theory, while all modal damping ratios are constrained to be greater than zero.

Findings

Several comprehensive examples are presented to demonstrate the accuracy and effectiveness of the proposed method, and comparisons with existing approaches are provided whenever possible.

Originality/value

The proposed method is highly efficient and allows the damping ratios to be conveniently specified for all significant modes, producing optimal damping coefficients in practical applications.

Details

Engineering Computations, vol. 34 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 8 May 2007

Bin Wu, Bing‐Hai Zhou and Li‐Feng Xi

This paper aims to develop a service‐oriented distributed multi‐robot system based on manufacturing message specification (MMS) and new‐generation distributed object technology �…

1525

Abstract

Purpose

This paper aims to develop a service‐oriented distributed multi‐robot system based on manufacturing message specification (MMS) and new‐generation distributed object technology – web services for realizing remotely monitoring and controlling multiple heterogeneous robots in the internet environment.

Design/methodology/approach

The study presents robot communication model and distributed multi‐robot monitoring and control software structure based on MMS and web services. In particular, monitoring and control software design of MMS concepts in web services environment using Unified Modeling Language model is discussed in detail. In addition, to verify the validity of the proposed design method, a multi‐robot prototype system for robot flexible assemble cell has been achieved. Its Server software is implemented in C++ with Visual Studio.NET being the development environment and Client software is programmed in Java with Borland JBuilder 9 being the development tool.

Findings

Finds that the communication structure following MMS can make the multi‐robot monitoring and control system have perfect robustness, interoperability and reconfigurability. Besides, web services technology can conveniently realize MMS services, also can successfully resolve the remote multi‐robot monitoring and control problem among cross‐network, cross‐platform and heterogeneous systems.

Research limitations/implications

Provides an easy and low‐cost method for realizing heterogeneous multi‐robot remote driving. The web‐based distribution of the presented system is critical in enabling capabilities such as e‐manufacturing, e‐diagnostics and e‐maintenance.

Practical implications

The proposed system can be seamlessly integrated into other automated manufacturing systems or management systems in plug‐and‐play fashion. The combination of MMS and web services is in favor of real manufacturing equipments being embedded in the network, so the presented systematic methodology can be a useful reference for constructing web‐based reconfigurable manufacturing systems.

Originality/value

Provides robot communication model based on MMS and web services and presents service‐oriented distributed remote multi‐robot monitoring and control software architecture.

Details

Industrial Robot: An International Journal, vol. 34 no. 3
Type: Research Article
ISSN: 0143-991X

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