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Optimal design of aluminium extrusion dies using a novel geometry based approach. / Chao Lin

Swansea University Author: Chao Lin

Abstract

Aluminium extrusion is a forming process used for manufacturing straight and long aluminium products. Among all aspects of the process, extrusion die design is the key issue for producing high-quality extrudates. The approaches to design extrusion dies can be broadly classified into three groups; tr...

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Published: 2005
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42734
first_indexed 2018-08-02T18:55:25Z
last_indexed 2018-08-03T10:10:57Z
id cronfa42734
recordtype RisThesis
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spelling 2018-08-02T16:24:30.2738035 v2 42734 2018-08-02 Optimal design of aluminium extrusion dies using a novel geometry based approach. 1c5d9fc9d47daad2c201e954b4f0fe7b NULL Chao Lin Chao Lin true true 2018-08-02 Aluminium extrusion is a forming process used for manufacturing straight and long aluminium products. Among all aspects of the process, extrusion die design is the key issue for producing high-quality extrudates. The approaches to design extrusion dies can be broadly classified into three groups; trial and error, empirical based approach and numerical simulation based approaches. By using the first two methodologies, the quality of extrusion die designs are intrinsically and strongly linked with designers' experience and skill. As the required forms for extrusions become more complex, these two approaches becomes less useful. Besides, since the design knowledge is held by designers, it is more often a 'black art', and the personnel movement can influence the design work significantly. On the other hand, with the advent of computers and greatly enhanced computing capability, many new approaches have been introduced for designing extrusion dies in last few decades. However, even with the current computing power, the numerical simulation approach has its limitations, particular in time required and even accuracy. Extrusion process involves complex constitutive relationships and large deformation of material. To overcome the limitations posed by current available design approaches, a new geometry based methodology has been proposed in this thesis. The new methodology combines empirical design formulae, geometry reasoning technique and optimization algorithm together. The work originates from the earlier work done by Miles et al. [1, 2, 3, 4], and Armstrong and his colleagues [5, 6, 7, 8, 9, 10, 11, 12], In this research work, a new knowledge representation scheme is developed so that historical data can be easily gathered and reused. By using empirical bearing length design formulae with historical data, a new bearing length estimation approach is introduced so that new profiles can be designed based on past good designs. A novel die layout design approach has also been developed and validated. This new method uses bearing length estimation algorithms with maximum bearing length difference to give radial or fiat layout for single/multi-hole dies. By using medial axis transform, a set of new geometry reasoning algorithms have been studied. These algorithms give a general and robust way to analyze two-dimensional geometry shapes. A brand-new die profile categories have been proposed to avoid the drawbacks held by current classification. A new algorithm and a set of new classifying criteria have been introduced. Based on medial axis transform and geometry reasoning technique, extrusion die profiles can be classified into different category correctly and efficiently. This research work shows that all the proposed approaches give several feedback paths in extrusion die design process. Therefore, not only historical data can be reused for new designs, but it is also possible to acquire and represent design knowledge and to optimize the whole design process. E-Thesis Materials science. 31 12 2005 2005-12-31 COLLEGE NANME Engineering COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-02T16:24:30.2738035 2018-08-02T16:24:30.2738035 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised Chao Lin NULL 1 0042734-02082018162517.pdf 10807503.pdf 2018-08-02T16:25:17.7930000 Output 19435983 application/pdf E-Thesis true 2018-08-02T16:25:17.7930000 false
title Optimal design of aluminium extrusion dies using a novel geometry based approach.
spellingShingle Optimal design of aluminium extrusion dies using a novel geometry based approach.
Chao Lin
title_short Optimal design of aluminium extrusion dies using a novel geometry based approach.
title_full Optimal design of aluminium extrusion dies using a novel geometry based approach.
title_fullStr Optimal design of aluminium extrusion dies using a novel geometry based approach.
title_full_unstemmed Optimal design of aluminium extrusion dies using a novel geometry based approach.
title_sort Optimal design of aluminium extrusion dies using a novel geometry based approach.
author_id_str_mv 1c5d9fc9d47daad2c201e954b4f0fe7b
author_id_fullname_str_mv 1c5d9fc9d47daad2c201e954b4f0fe7b_***_Chao Lin
author Chao Lin
author2 Chao Lin
format E-Thesis
publishDate 2005
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
document_store_str 1
active_str 0
description Aluminium extrusion is a forming process used for manufacturing straight and long aluminium products. Among all aspects of the process, extrusion die design is the key issue for producing high-quality extrudates. The approaches to design extrusion dies can be broadly classified into three groups; trial and error, empirical based approach and numerical simulation based approaches. By using the first two methodologies, the quality of extrusion die designs are intrinsically and strongly linked with designers' experience and skill. As the required forms for extrusions become more complex, these two approaches becomes less useful. Besides, since the design knowledge is held by designers, it is more often a 'black art', and the personnel movement can influence the design work significantly. On the other hand, with the advent of computers and greatly enhanced computing capability, many new approaches have been introduced for designing extrusion dies in last few decades. However, even with the current computing power, the numerical simulation approach has its limitations, particular in time required and even accuracy. Extrusion process involves complex constitutive relationships and large deformation of material. To overcome the limitations posed by current available design approaches, a new geometry based methodology has been proposed in this thesis. The new methodology combines empirical design formulae, geometry reasoning technique and optimization algorithm together. The work originates from the earlier work done by Miles et al. [1, 2, 3, 4], and Armstrong and his colleagues [5, 6, 7, 8, 9, 10, 11, 12], In this research work, a new knowledge representation scheme is developed so that historical data can be easily gathered and reused. By using empirical bearing length design formulae with historical data, a new bearing length estimation approach is introduced so that new profiles can be designed based on past good designs. A novel die layout design approach has also been developed and validated. This new method uses bearing length estimation algorithms with maximum bearing length difference to give radial or fiat layout for single/multi-hole dies. By using medial axis transform, a set of new geometry reasoning algorithms have been studied. These algorithms give a general and robust way to analyze two-dimensional geometry shapes. A brand-new die profile categories have been proposed to avoid the drawbacks held by current classification. A new algorithm and a set of new classifying criteria have been introduced. Based on medial axis transform and geometry reasoning technique, extrusion die profiles can be classified into different category correctly and efficiently. This research work shows that all the proposed approaches give several feedback paths in extrusion die design process. Therefore, not only historical data can be reused for new designs, but it is also possible to acquire and represent design knowledge and to optimize the whole design process.
published_date 2005-12-31T19:41:17Z
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score 11.048302

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