Search results

1 – 10 of 31
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 1 January 2012

Anders Larsen, Mathias Stolpe and J.H. Hattel

The purpose of this paper is to determine the magnitude and spatial distribution of the heat transfer coefficient between the workpiece and the backing plate in a friction stir…

419

Abstract

Purpose

The purpose of this paper is to determine the magnitude and spatial distribution of the heat transfer coefficient between the workpiece and the backing plate in a friction stir welding process using inverse modelling.

Design/methodology/approach

The magnitude and distribution of the heat transfer coefficient are the variables in an optimisation problem. The objective is to minimise the difference between experimentally measured temperatures and temperatures obtained using a 3D finite element model. The optimisation problem is solved using a gradient based optimisation method. This approach yields optimal values for the magnitude and distribution of the heat transfer coefficient.

Findings

It is found that the heat transfer coefficient between the workpiece and the backing plate is non-uniform and takes its maximum value in a region below the welding tool. Four different parameterisations of the spatial distribution of the heat transfer coefficient are analysed and a simple, two parameter distribution is found to give good results.

Originality/value

The heat transfer from workpiece to backing plate is important for the temperature field in the workpiece, and in turn the mechanical properties of the welded plate. Accurate modelling of the magnitude and distribution of the heat transfer coefficient is therefore an essential step towards improved models of the process. This is the first study using a gradient based optimisation method and a non-uniform parameterisation of the heat transfer coefficient in an inverse modeling approach to determine the heat transfer coefficient in friction stir welding.

Details

Engineering Computations: International Journal for Computer-Aided Engineering and Software, vol. 29 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Access Restricted. View access options
Article
Publication date: 16 November 2010

Robert Hamilton, Donald MacKenzie and Hongjun Li

The friction stir welding (FSW) process comprises several highly coupled (and non‐linear) physical phenomena: large plastic deformation, material flow transportation, mechanical…

3390

Abstract

Purpose

The friction stir welding (FSW) process comprises several highly coupled (and non‐linear) physical phenomena: large plastic deformation, material flow transportation, mechanical stirring of the tool, tool‐workpiece surface interaction, dynamic structural evolution, heat generation from friction and plastic deformation. This paper aims to present an advanced finite element (FE) model encapsulating this complex behaviour and various aspects associated with the FE model such as contact modelling, material model and meshing techniques are to be discussed in detail.

Design/methodology/approach

The numerical model is continuum solid mechanics‐based, fully thermo‐mechanically coupled and has successfully simulated the FSW process including plunging, dwelling and welding stages.

Findings

The development of several field variables are quantified by the model: temperature, stress, strain. Material movement is visualized by defining tracer particles at the locations of interest. The numerically computed material flow patterns are in very good agreement with the general findings from experiments.

Originality/value

The model is, to the best of the authors' knowledge, the most advanced simulation of FSW published in the literature.

Details

Engineering Computations, vol. 27 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

Access Restricted. View access options
Article
Publication date: 1 January 2008

P. Sathiya, N. Siva Shanmugam, T. Ramesh and R. Murugavel

Friction stir welding (FSW), a process that involves joining of metals without fusion of filler materials. It is used already in routine, as well as critical application for the…

514

Abstract

Friction stir welding (FSW), a process that involves joining of metals without fusion of filler materials. It is used already in routine, as well as critical application for the joining of structural components made of Aluminum and its alloys. Indeed it has been convincingly demonstrated that the process results in strong and ductile joints, some times in systems, which have proved difficult using conventional welding techniques. The process is most suitable for components that are flat & long (plates & sheets) but it can be adapted for pipes, hollow sections and positional welding. The welds are created by the combined action of frictional heating and mechanical deformation, due to a rotating tool. Recently, a new technology called friction stir spot welding (FSSW) has been developed that has a several advantages over the electric resistance welding process widely used in automotive industry in terms of weld quality and process efficiency. This welding technology involves a process similar to FSW, except that, instead of moving the tool along the weld seam, the tool only indents the parts, which are placed on top of each other. The conditions under which the deposition process in FSSW is successful are not fully understood. However, it is known that only under specific thermo‐mechanical conditions does a weld formation occur. The objective of the present work is to analyze the primary conditions under which the cavity behind the tool is filled. For this, a fully coupled thermo‐mechanical three‐dimensional FE model has been developed in ABAQUS/Explicit using the adaptive meshing scheme and the Johnson‐Cook material law. The contact forces are modeled by Coulomb’s law of friction, making the contact condition highly solution dependent. Temperature graph in the radial direction as well as stress, strain plots are presented.

Details

Multidiscipline Modeling in Materials and Structures, vol. 4 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

Access Restricted. View access options
Article
Publication date: 14 October 2020

Christopher Gottlieb Klingaa, Sankhya Mohanty and Jesper Henri Hattel

Conformal cooling channels in additively manufactured molds are superior over conventional channels in terms of cooling control, part warpage and lead time. The heat transfer…

299

Abstract

Purpose

Conformal cooling channels in additively manufactured molds are superior over conventional channels in terms of cooling control, part warpage and lead time. The heat transfer ability of cooling channels is determined by their geometry and surface roughness. Laser powder bed fusion manufactured channels have an inherent process-induced dross formation that may significantly alter the actual shape of nominal channels. Therefore, it is crucial to be able to predict the expected surface roughness and changes in the geometry of metal additively manufactured conformal cooling channels. The purpose of this paper is to present a new methodology for predicting the realistic design of laser powder bed fusion channels.

Design/methodology/approach

This study proposes a methodology for making nominal channel design more realistic by the implementation of roughness prediction models. The models are used for altering the nominal shape of a channel to its predicted shape by point cloud analysis and manipulation.

Findings

A straight channel is investigated as a simple case study and validated against X-ray computed tomography measurements. The modified channel geometry is reconstructed and meshed, resulting in a predicted, more realistic version of the nominal geometry. The methodology is successfully tested on a torus shape and a simple conformal cooling channel design. Finally, the methodology is validated through a cooling test experiment and comparison with simulations.

Practical implications

Accurate prediction of channel surface roughness and geometry would lead toward more accurate modeling of cooling performance.

Originality/value

A robust start to finish method for realistic geometrical prediction of metal additive manufacturing cooling channels has yet to be proposed. The current study seeks to fill the gap.

Access Restricted. View access options
Article
Publication date: 21 June 2013

M. Selvaraj, Vela Murali and S.R. Koteswara Rao

The purpose of this paper is to propose a three‐dimensional thermal model for friction stir welding of AISI 1018 mild steel to predict the thermal cycle, temperature distribution…

458

Abstract

Purpose

The purpose of this paper is to propose a three‐dimensional thermal model for friction stir welding of AISI 1018 mild steel to predict the thermal cycle, temperature distribution, the effect of welding parameters on power required, heat generation and peak temperature during the friction stir welding process.

Design/methodology/approach

The mathematical expressions for heat generation during the friction stir welding process were derived. The simulations for various welding and rotational speeds were carried out on ANSYS software employing temperature and radius dependent moving heat source and applying the boundary conditions.

Findings

The predicted thermal cycle, torque required and temperatures were found to be in good agreement with the experimental results. The heat generation and peak temperatures were found to be directly proportional to rotational speed and inversely proportional to welding speed. The rate of increase in heat generation and peak temperature were found to be higher at lower rotational speeds and lower at higher rotational speeds. The heat generation during friction stir welding was found to be 71.4 per cent at shoulder, 23.1 per cent at pin side and 5.5 per cent at bottom of the pin.

Originality/value

A new temperature dependent slip factor has been used to determine the contribution of slipping and sticking on total heat generation. A temperature and radius dependent moving heat source has been employed.

Details

Multidiscipline Modeling in Materials and Structures, vol. 9 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

Access Restricted. View access options
Article
Publication date: 23 August 2021

Iván La Fé-Perdomo, Jorge Andres Ramos-Grez, Gerardo Beruvides and Rafael Alberto Mujica

The purpose of this paper is to outline some key aspects such as material systems used, phenomenological and statistical process modeling, techniques applied to monitor the…

719

Abstract

Purpose

The purpose of this paper is to outline some key aspects such as material systems used, phenomenological and statistical process modeling, techniques applied to monitor the process and optimization approaches reported. All these need to be taken into account for the ongoing development of the SLM technique, particularly in health care applications. The outcomes from this review allow not only to summarize the main features of the process but also to collect a considerable amount of investigation effort so far achieved by the researcher community.

Design/methodology/approach

This paper reviews four significant areas of the selective laser melting (SLM) process of metallic systems within the scope of medical devices as follows: established and novel materials used, process modeling, process tracking and quality evaluation, and finally, the attempts for optimizing some process features such as surface roughness, porosity and mechanical properties. All the consulted literature has been highly detailed and discussed to understand the current and existing research gaps.

Findings

With this review, there is a prevailing need for further investigation on copper alloys, particularly when conformal cooling, antibacterial and antiviral properties are sought after. Moreover, artificial intelligence techniques for modeling and optimizing the SLM process parameters are still at a poor application level in this field. Furthermore, plenty of research work needs to be done to improve the existent online monitoring techniques.

Research limitations/implications

This review is limited only to the materials, models, monitoring methods, and optimization approaches reported on the SLM process for metallic systems, particularly those found in the health care arena.

Practical implications

SLM is a widely used metal additive manufacturing process due to the possibility of elaborating complex and customized tridimensional parts or components. It is corroborated that SLM produces minimal amounts of waste and enables optimal designs that allow considerable environmental advantages and promotes sustainability.

Social implications

The key perspectives about the applications of novel materials in the field of medicine are proposed.

Originality/value

The investigations about SLM contain an increasing amount of knowledge, motivated by the growing interest of the scientific community in this relatively young manufacturing process. This study can be seen as a compilation of relevant researches and findings in the field of the metal printing process.

Access Restricted. View access options
Article
Publication date: 28 October 2022

Jaydeepsinh M. Ravalji and Shruti J. Raval

Selective laser melting and electron beam melting processes are well-known for the additive manufacturing of metal parts. Metal powder bed fusion (MPBF) is a common term for them…

350

Abstract

Purpose

Selective laser melting and electron beam melting processes are well-known for the additive manufacturing of metal parts. Metal powder bed fusion (MPBF) is a common term for them. The MPBF process can empower the manufacturing of intricate shapes by reducing the use of special tools, shortening the supply chain and allowing small batches. However, the MPBF process suffers from many quality issues. In literature, several works are recorded for qualification of the MPBF part. The purpose of this study is to recollect those works done for quality control and report their helpful findings for further research and development.

Design/methodology/approach

A systematic literature review was conducted to highlight the major quality issues in the MPBF process and its root causes. Further, the works reported in the literature for mitigation of these issues are classified and discussed in five categories: experimental investigation, finite element method-based numerical models, physics-based analytical models, in-situ control using artificial intelligence (AI) and machine learning (ML) methods and statistical approaches. A comparison is also prepared among these strategies based on their suitability and limitations. Additionally, improvements in MPBF printers are pointed out to enhance the part quality.

Findings

Analytical models require less computational time to simulate the MPBF process and need a smaller number of experiments to confirm the results. They can be used as an efficient process parameter planning tool to print metal parts for noncritical applications. The AI-ML based quality control is also suitable for MPBF processes as it can control many processing parameters that may affect the quality of the MPBF part. Moreover, capabilities of MPBF printers like thinner layer thickness, smaller beam diameter, multiple lasers and high build temperature range can help in quality control.

Research limitations/implications

This study converts the piecemeal data on MPBF part qualification methods into interesting information and presents it in tabular form under each strategy. This tabular information provides the basis for further quality improvement efforts in the MPBF process.

Originality/value

This study references researchers and practitioners on recent quality control efforts and their significant findings for a better quality of MPBF part.

Details

Rapid Prototyping Journal, vol. 29 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Available. Open Access. Open Access
Article
Publication date: 5 December 2024

Elisa Torresani, Alberto Cabo Rios, Thomas Grippi, Andrii L. Maximenko, Marco Zago, Ilaria Cristofolini and Eugene A. Olevsky

This study aims to provide understanding of the influence of external factors, such as gravity, during sintering of three dimensional (3D)-printed parts in which the initial…

135

Abstract

Purpose

This study aims to provide understanding of the influence of external factors, such as gravity, during sintering of three dimensional (3D)-printed parts in which the initial relative density and cohesion between the powder particles are lower compared with those present in the green parts produced by traditional powder technologies. A developed model is used to predict shrinkage and shape distortion of 3D-printed powder components at high sintering temperatures.

Design/methodology/approach

Three cylindrical shape connector geometries are designed, including horizontal and vertical tubes of different sizes. Several samples are manufactured by binder jetting to validate the model, and numerical results are compared with the measurements of the sintered shape.

Findings

Simulations are consistent with empirical data, proving that the continuum theory of sintering can effectively predict sintering deformation in additively manufactured products.

Originality/value

This work includes the assessment of the accuracy and limits of a multiphysics continuum mechanics–based sintering model in predicting gravity-induced distortions in complex-shaped additively manufactured components.

Details

Rapid Prototyping Journal, vol. 30 no. 11
Type: Research Article
ISSN: 1355-2546

Keywords

Access Restricted. View access options
Article
Publication date: 30 December 2024

Giulio Poggiana, Matteo Zorzetto, Francesco Lucchini, Riccardo Torchio, Michele Forzan and Fabrizio Dughiero

Recent progress in additive manufacturing methods alleviated manufacturing constraints on devices. Topology optimization (TO) methods can leverage these reduced limitations and…

26

Abstract

Purpose

Recent progress in additive manufacturing methods alleviated manufacturing constraints on devices. Topology optimization (TO) methods can leverage these reduced limitations and this paper aims to study the use of these algorithms in induction heating for injection molding.

Design/methodology/approach

In this paper, TO is used to reduce the volume of ferrite in an injection molding tool while aiming at maximizing the performance of the device. Characteristics of the proposed solution such as efficiency and power density are compared to the ones of the original device.

Findings

The study shows that it is possible to reduce significantly the amount of ferrite used without impacting the efficiency. The thermal performances of the proposed solution present also slight improvements compared to the original solution.

Originality/value

Optimization algorithms are important for understanding how to design efficient electrical devices. In this paper, the application of TO for injection molding applications presents a new perspective in designing such components.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 2 February 2015

Yunfei Du, Chuntian Li, Bin Huang, Ming Tang and Changhua Du

This paper aims to identify a variety of binary system solders by alloying, and relevantly derive multiple system Pb-free solders from the former, attempting to replace the high…

348

Abstract

Purpose

This paper aims to identify a variety of binary system solders by alloying, and relevantly derive multiple system Pb-free solders from the former, attempting to replace the high temperature Sn-Pb solder.

Design/methodology/approach

The basis of the paper is the synthesis of previous studies. In terms of some binary high temperature solder alloys, such as Au-20Sn, Bi-2.5Ag, Sn-5Sb, Au-12.5Ge, Zn-6Al and Zn-Sn, taking the alloy phase diagram as the starting point, the melting characteristics, microstructure, mechanical properties, wetting ability and reliability of solder joint are analysed and the prospect is consequently indicated.

Findings

Based on the analysis of the six groups of Pb-free solders, the present binary system solder alloys, from the perspective of melting properties, mechanical properties, soldering or reliability of solder joint, rarely meet the comprehensive requirements of replacing the high-temperature Sn-Pb solder. It is assumed to be a solution that multiple-system Pb-free solders derive from a variety of binary system solders by means of alloying. The future development of high temperature Pb-free solder may focus on some factors such as physical properties, mechanical properties, processing, reliability of solder joint, environmental performance and expense.

Originality/value

The paper concentrates on the issue of Pb-free solders at high temperature. From a specific perspective of binary system solders, the presently available Pb-free solders are suggested from the starting point of the alloy phase diagram and the prospect of alternatives of Sn-Pb solders at high temperature are indicated.

Details

Soldering & Surface Mount Technology, vol. 27 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

1 – 10 of 31
Per page
102050