Browsing by Author "Ding, J."

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Design for wire and arc additive layer manufacture
    (2010-04-19T00:00:00Z) Mehnen, Jorn; Ding, J.; Lockett, Helen L.; Kazanas, P.; Bernard, A.
    Additive Layer Manufacture (ALM) is a technique whereby freeform structures are produced by building up material in layers. RUAM (Ready-to-Use Additive Layer Manufacturing) is an innovative concept for building large scale metal ready-to- use parts. The design for RUAM has several process steps: the geometric design of the parts taking the complex process behaviour of the arc welding process into account; FEM to predict temperature and stress distributions to minimise part distortions; and efficient robot tool path design. This paper covers these essential design steps from a technical as well as practical point of view.
  • Thumbnail Image
    ItemOpen Access
    Thermo-mechanical analysis of wire and arc additive layer manufacturing process on large multi-layer parts
    (Elsevier Science B.V., Amsterdam., 2011-12-01T00:00:00Z) Ding, J.; Colegrove, Paul A.; Mehnen, Jorn; Ganguly, Supriyo; Sequeira Almeida, P. M.; Wang, F.; Williams, Stewart W.
    Wire and Arc Additive Layer Manufacturing (WAALM) is gaining increasing popularity as the process allows the production of large custom-made metal workpieces with high deposition rates. The high power input of the welding process, causes significant residual stress and distortion of the workpiece. This paper describes the thermo-mechanical behaviour of the multi-layer wall structure made by the WAALM process. A 3D thermo-elastic–plastic transient model and a model based on an advanced steady-state thermal analysis are employed in this study. This modelling approach shows a significant advantage with respect to the computational time. The temperature simulations and distortion predictions are verified by comparing with the experimental results from thermo- couples and laser scanners, while the residual stresses are verified with the neutron diffraction strain scanner ENGIN-X. The stress across the deposited wall is found uniform with very little influence of the preceding layers on the following layers. The stress redistributed after unclamping with a much lower value at the top of the wall than at the interface due to the bending distortion of the sampl
  • Thumbnail Image
    ItemOpen Access
    Thermo-mechanical analysis of wire and arc additive manufacturing process
    (Cranfield University, 2012-01) Ding, J.; Williams, Stewart W.
    Conventional manufacturing processes often require a large amount of machining and cannot satisfy the continuously increasing requirements of a sustainable, low cost, and environmentally friendly modern industry. Thus, Additive Manufacturing (AM) has become an important industrial process for the manufacture of custom-made metal workpieces. Among the different AM processes, Wire and Arc Additive Manufacture (WAAM) has the ability to manufacture large, low volume metal work-pieces due to its high deposition rate. In this process, 3D metallic components are built by depositing beads of weld metal in a layer by layer fashion. However, the non-uniform expansion and contraction of the material during the thermal cycle results in residual stresses and distortion. To obtain a better understanding of the thermo-mechanical performance of the WAAM process, a study based on FE simulation was untaken in this thesis. The mechanism of the stress generation during the deposition process was analysed via a 3D transient thermo-mechanical FE model which is verified with experimental results. To be capable of analysing the thermo-mechanical behaviour of large-scale WAAM components, an efficient FE approach was developed which can significantly reduce the computational time. The accuracy of this model was validated against the transient model as well as experimental measurements. With the help of the FE models studies on different deposition parameters, deposition sequences and deposition strategies were carried out. It has been proved that the residual stresses and the distortions are possible to be reduced by using optimised deposition parameters and sequences. In addition, a robot path generation prototype has been developed to help efficiently integrate these optimised process settings in the real-wold WAAM process.