With digital equipment becoming increasingly networked, either on wired or wireless networks, for personal and professional use alike, distributed software systems have become a crucial element in information and communications technologies. The study of these systems forms the core of the ARLES' work, which is specifically concerned with defining new system software architectures, based on the use of emerging networking technologies. In this context, we concentrate on the study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence.

반도체 공정 overview

Composites science and technology

https://cyberleninka.org/article/n/403409.pdf

A review of numerical analysis of friction stir welding

Friction stir welding: Process, automation, and control

Friction stir welding/processing of metals and alloys: A comprehensive review on microstructural evolution

This paper presents on-going finite element modeling efforts of friction stir spot welding (FSSW) process by an explicit finite element code. Adaptive meshing and advection schemes, which makes it possible to maintain mesh quality under large deformations, is utilized to simulate the material flow and temperature distribution in FSSW process. The predicted overall deformation shape of the weld joint resembles that experimentally observed. Temperature and stress graphs in the radial direction as well as temperature-deformation distribution plots are presented. However, refinements of several modeling aspects are needed for more realistic prediction of the FSSW process.

Thermo-Mechanical Modeling of Friction Stir Spot Welding (FSSW) Process: Use of an Explicit Adaptive Meshing Scheme

Friction Stir Welding (FSW) is a novel kind of welding for joining metals that are impossible or difficult to weld by conventional methods. Three-dimensional nature of FSW makes the experimental investigation more complex. Moreover, experimental observations are often costly and time consuming, and usually there is an inaccuracy in measuring the data during experimental tests. Thus, Finite Element Methods (FEMs) has been employed to overcome the complexity, to increase the accuracy and also to reduce costs. It should be noted that, due to the presence of large deformations of the material during FSW, strong distortions of mesh might be happened in the numerical simulation. Therefore, one of the most significant considerations during the process simulation is the selection of the best numerical approach. It must be mentioned that; the numerical approach selection determines the relationship between the finite grid (mesh) and deforming continuum of computing zones. Also, numerical approach determines the ability of the model to overcome large distortions of mesh and provides an accurate resolution of boundaries and interfaces. There are different descriptions for the algorithms of continuum mechanics include Lagrangian and Eulerian. Moreover, by combining the above-mentioned methods, an Arbitrary Lagrangian–Eulerian (ALE) approach is proposed. In this paper, a comparison between different numerical approaches for thermal analysis of FSW at both local and global scales is reviewed and the applications of each method in the FSW process is discussed in detail. Observations showed that, Lagrangian method is usually used for modelling thermal behavior in the whole structure area, while Eulerian approach is seldom employed for modelling of the thermal behavior, and it is usually employed for modelling the material flow. Additionally, for modelling of the heat affected zone, ALE approach is found to be as an appropriate approach. Finally, several significant challenges and subjects remain to be addressed about FSW thermal analysis and opportunities for the future work are proposed.

A Comparison of Different Finite Element Methods in the Thermal Analysis of Friction Stir Welding (FSW)

Effective and reliable computational models would greatly enhance the study of energy dissipation during the friction stir spot welding (FSSW) process. Approaches for the computational modeling of the FSSW process, however, are still under development, and much work is still needed, particularly the application of explicit finite element (FE) codes for a verifiable simulation. The objectives of this work are to develop an FE modeling of FSSW of 6061-T6 aluminum alloy and analyze energy generation during the welding process. In this work, a three dimensional (3-D) FE coupled thermal-stress model of FSSW process has been developed in Abaqus/Explicit code. Rate dependent Johnson–Cook material model is used for elastic–plastic work deformations. Temperature profile and energy dissipation history of the FE model have been analyzed. The peak temperature at the tip of the pin and frictional dissipation energy are in close agreement with the experimental work done by Gerlich et al. [1], which is about 5.1% different.

Energy generation during friction stir spot welding (FSSW) of al 6061-T6 plates

Modeling the tensile stress–strain response of carbon nanotube/polypropylene nanocomposites using nonlinear representative volume element

Evaluation of mechanical and interfacial properties of friction welded alumina-mild steel rods with the use of Al6061 sheet are presented in this work. SEM, EDX analysis, hardness and bending strength tests were conducted. The bonds were attained through interfacial interlocking and intermetalllic phase formation with average bending strengths in the range of 40 to 200 MPa and insignificant hardness change in the parent alumina and mild steel. A preliminary simulation was made to predict the deformation, stress, strain and temperature distribution during the joining operation using a fully coupled thermo-mechanical FE model. The aluminum alloy metal being rubbed was simulated using a phenomenological Johnson-Cook viscoplasticity material model, which suited for materials subjected to large strains, high strain rates and high temperatures. The highest stress, strain and deformation are found to be within the heat affected zone of the weld close to the periphery rubbing surface region and correspond to the highest temperature profiles observed.

Mokhtar Awang

Papers

Thermo-Mechanical Modeling of Friction Stir Spot Welding (FSSW) Process: Use of an Explicit Adaptive Meshing Scheme

A Comparison of Different Finite Element Methods in the Thermal Analysis of Friction Stir Welding (FSW)

Energy generation during friction stir spot welding (FSSW) of al 6061-T6 plates

Modeling the tensile stress–strain response of carbon nanotube/polypropylene nanocomposites using nonlinear representative volume element

Evaluation of properties and FEM Model of the Friction welded mild Steel-Al6061-Alumina