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Full-Text Articles in Engineering
Shape Optimisation Of Cold-Formed Steel Columns With Manufacturing Constraints Using The Hough Transform, Bin Wang, Benoit P. Gilbert, Adrien M. Molinier, Hong Guan, Lip H. Teh
Shape Optimisation Of Cold-Formed Steel Columns With Manufacturing Constraints Using The Hough Transform, Bin Wang, Benoit P. Gilbert, Adrien M. Molinier, Hong Guan, Lip H. Teh
Faculty of Engineering and Information Sciences - Papers: Part A
This paper introduces manufacturing constraints into a recently developed evolutionary algorithm for shape optimisation of CFS profiles. The algorithm is referred to as "self-shape optimisation" and uses Genetic Algorithm (GA) together with the Augmented Lagrangian (AL) method to avoid ill-conditioned problems. Simple manufacturing rules derived from the limitations of current cold-forming processes, i.e. a limited ability to form continuously curved surfaces without discrete bends, are described in the paper and incorporated into the algorithm. The Hough transform is used to detect straight lines and transform arbitrarily drawn cross-sections into manufacturable ones. Firstly, the algorithm is verified against a known optimisation …
Towards An Automated Robotic Arc-Welding-Based Additive Manufacturing System From Cad To Finished Part, Donghong Ding, Chen Shen, Zengxi Stephen Pan, Dominic Cuiuri, Hui Jun Li, Nathan P. Larkin, Stephen Van Duin
Towards An Automated Robotic Arc-Welding-Based Additive Manufacturing System From Cad To Finished Part, Donghong Ding, Chen Shen, Zengxi Stephen Pan, Dominic Cuiuri, Hui Jun Li, Nathan P. Larkin, Stephen Van Duin
Faculty of Engineering and Information Sciences - Papers: Part A
Arc welding has been widely explored for additive manufacturing of large metal components over the last three decades due to its lower capital cost, an unlimited build envelope, and higher deposition rates. Although significant improvements have been made, an arc welding process has yet to be incorporated in a commercially available additive manufacturing system. The next step in exploiting "true" arc-welding-based additive manufacturing is to develop the automation software required to produce CAD-to-part capability. This study focuses on developing a fully automated system using robotic gas metal arc welding to additively manufacture metal components. The system contains several modules, including …
Fabricating Superior Nial Bronze Components Through Wire Arc Additive Manufacturing, Donghong Ding, Zengxi Stephen Pan, Stephen Van Duin, Hui Jun Li, Chen Shen
Fabricating Superior Nial Bronze Components Through Wire Arc Additive Manufacturing, Donghong Ding, Zengxi Stephen Pan, Stephen Van Duin, Hui Jun Li, Chen Shen
Faculty of Engineering and Information Sciences - Papers: Part A
Cast nickel aluminum bronze (NAB) alloy is widely used for large engineering components in marine applications due to its excellent mechanical properties and corrosion resistance. Casting porosity, as well as coarse microstructure, however, are accompanied by a decrease in mechanical properties of cast NAB components. Although heat treatment, friction stir processing, and fusion welding were implemented to eliminate porosity, improve mechanical properties, and refine the microstructure of as-cast metal, their applications are limited to either surface modification or component repair. Instead of traditional casting techniques, this study focuses on developing NAB components using recently expanded wire arc additive manufacturing (WAAM). …
Stress In Thin Wall Structures Made By Layer Additive Manufacturing, Vladimir Luzin, Nicholas P. Hoye
Stress In Thin Wall Structures Made By Layer Additive Manufacturing, Vladimir Luzin, Nicholas P. Hoye
Faculty of Engineering and Information Sciences - Papers: Part A
Manufacturing of thin wall structures is one of the main applications of additive manufacturing, where it has significant advantages over traditional milling and machining techniques or welded analogues. Such thin walled structures are common in structural aerospace components, and are also frequently made from titanium alloys. For such large-scale components, layer deposition strategy is more advantageous rather than a pixel-wise deposition approach due to the demand for high productivity and size requirements. Several techniques can be used to produce layer-wise build-ups, including laser-powered Direct Metal Deposition (DMD) process or gas tungsten arc welding (GTAW). Although, in the general case of …
A Practical Path Planning Methodology For Wire And Arc Additive Manufacturing Of Thin-Walled Structures, Donghong Ding, Zengxi Pan, Dominic Cuiuri, Huijun Li
A Practical Path Planning Methodology For Wire And Arc Additive Manufacturing Of Thin-Walled Structures, Donghong Ding, Zengxi Pan, Dominic Cuiuri, Huijun Li
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents a novel methodology to generate deposition paths for wire and arc additive manufacturing (WAAM). The medial axis transformation (MAT), which represents the skeleton of a given geometry, is firstly extracted to understand the geometry. Then a deposition path that is based on the MAT is efficiently generated. The resulting MAT-based path is able to entirely fill any given cross-sectional geometry without gaps. With the variation of step-over distance, material efficiency alters accordingly for both solid and thin-walled structures. It is found that thin-walled structures are more sensitive to step-over distance in terms of material efficiency. The optimal …
A Tool-Path Generation Strategy For Wire And Arc Additive Manufacturing, Donghong Ding, Zengxi Stephen Pan, Dominic Cuiuri, Huijun Li
A Tool-Path Generation Strategy For Wire And Arc Additive Manufacturing, Donghong Ding, Zengxi Stephen Pan, Dominic Cuiuri, Huijun Li
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents an algorithm to automatically generate optimal tool-paths for the wire and arc additive manufacturing (WAAM) process for a large class of geometries. The algorithm firstly decomposes 2D geometries into a set of convex polygons based on a divide-and-conquer strategy. Then, for each convex polygon, an optimal scan direction is identified and a continuous tool-path is generated using a combination of zigzag and contour pattern strategies. Finally, all individual sub-paths are connected to form a closed curve. This tool-path generation strategy fulfils the design requirements of WAAM, including simple implementation, a minimized number of starting-stopping points, and high …
Finite Element Modelling Of Surface Roughness Transfer And Oxide Scale Micro Deformation In Metal Manufacturing Process, Zhengyi Jiang, Dongbin Wei, Hejie Li
Finite Element Modelling Of Surface Roughness Transfer And Oxide Scale Micro Deformation In Metal Manufacturing Process, Zhengyi Jiang, Dongbin Wei, Hejie Li
Faculty of Engineering and Information Sciences - Papers: Part A
In the paper, the micro deformation of oxide scale in hot strip rolling has been investigated with considering the friction effect. The finite element simulation of the micro deformation of oxide scale has been successfully conducted, and the calculated surface roughness is compared with the measured value, which shows a good agreement. A crystal plasticity finite element method (CPFEM) model was also successfully developed to analyse the surface roughness transfer during metal manufacturing. The simulation results show a good agreement with the experimental results in the flattening of surface asperity, and the surface roughness decreases significantly with an increase of …
Characterisation Of Metal Deposition During Additive Manufacturing Of Ti-6al-4v By Arc-Wire Methods, Nicholas Hoye, E C. Appel, Dominic Cuiuri, Hejie Li
Characterisation Of Metal Deposition During Additive Manufacturing Of Ti-6al-4v By Arc-Wire Methods, Nicholas Hoye, E C. Appel, Dominic Cuiuri, Hejie Li
Faculty of Engineering and Information Sciences - Papers: Part A
This study considers the use of the gas tungsten arc (GTA) welding process in conjunction with 'cold' wire addition to give layer-wise build-up of thin walled structures, simulating those commonly found in aerospace applications, which may in the future be manufactured by additive means. Taguchi DOE and multiple regression analysis methods have been applied to quantitatively establish relationships between common process parameters including arc length, arc current, travel speed and wire feed speed and resulting weld bead geometries and actual metal deposition rates. Mathematical expressions for build-up height, thickness and surface roughness are presented and evaluated against experimental data, with …