Journal of Materials Processing Technology 212 (2012) 1705–1715 Contents lists available at SciVerse ScienceDirect Journal of Materials Processing Technology jou rnal h om epa g e: www.elsevier.com/locate/jmatprotec Investigation on twisting distortion of thin plate stiffened structure under welding Jiangchao Wang a,∗ , Masakazu Shibahara b , Xudong Zhang c , Hidekazu Murakawa d a Graduate School of Engineering, Osaka University, 2-1 Yamadaoka Suita, Osaka 565-0871, Japan b Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuencho Nakaku Sakai, Osaka 599-8531, Japan c Hitachi Research Laboratory, 7-1-1 Omikacho Hitachi, Ibaraki 319-1292, Japan d Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka Ibaraki, Osaka 567-0047, Japan a r t i c l e i n f o Article history: Received 30 November 2011 Received in revised form 28 February 2012 Accepted 13 March 2012 Available online 21 March 2012 Keywords: Twisting distortion Large deformation Torsional buckling Elastic analysis Thermal elastic plastic FEA a b s t r a c t The welding distortion of thin plate was selected as research subject, which causes loss of dimensional control, structural integrity and increases fabrication costs for straightening. To study the characteristic of the welding distortion on thin plate structures, experiments were conducted. The test model was a thin plate stiffened structure and a large twisting distortion was observed. The welding distortion of the same structure was analyzed as a large deformation problem using a thermal elastic plastic FEM and an elastic FEM based on the concept of inherent deformation. The computed results by both methods showed the twisting distortion which is a typical buckling type deformation and the magnitude of this distortion agreed well with the experimental measurement. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Recently, the design of vehicle such as ship, automobile, train and aircraft in modern manufacturing emphasizes on minimiz- ing weight to improve fuel economy and enhance the carrying capability, the thin plate stiffened structure has became pop- ular. To assemble this kind of steel structures, the welding is widely employed as the main joining method with its significant advantages, however, the welding distortion is always the most complicated difficulties in construction of the welded structures, which not only decreases the geometrical precision but also delays the whole production schedule. Generally speaking, the welding distortion can be divided into the in-plane and out-of-plane dis- tortion. The welding shrinkage distortion is the typical in-plane type; for the out-of-plane type, there are different kinds of welding distortion, such as welding bending distortion, welding buckling distortion and so on. For the thin panel structures, the buckling type distortion can be produced by welding process, which is considered as the most critical mode compared with other welding distortion modes because of its instability and more difficult to straighten (Murakawa et al., 2011). ∗ Corresponding author. Tel.: +81 060 68798645; fax: +81 060 68798645. E-mail address: jcwang@jwri.osaka-u.ac.jp (J. Wang). For the welding buckling behavior, Masubuchi (1953) con- ducted the buckling type deformation of thin plate due to welding and presented the critical wave length influenced by the size of plate and welding conditions. Watanabe and Satoh (1957) observed the welding buckling distortion, the so-called concave–convex or convex–concave type, according to a series of experiments of bead on plate with thin plates; meanwhile, the critical force for buckling and the time when buckling occurs for welded plates with different aspect ratio is measured and studied (Watanabe and Satoh, 1958). Terasaki et al. (1998) also investigated the buckling behavior caused by welding utilizing the experiments, which show that the buck- ling welding distortion is affected by welding condition, the size of plate and material properties. Taking advantage of the numerical analysis and high perfor- mance computer, the investigation of buckling distortion under welding by computational approach is developed. Zhong et al. (1995) proposed an elastic finite element approach, which bases on the elastic large deflection theory of plate, utilizing the inherent strain as an equivalent load determined by the process conditions. Deo et al. (2003) examined the welding-induced buckling distor- tion by means of employing decoupled two- and three dimensional approaches, where the investigating process can be divided into two steps, firstly determining the residual stress based on a two- dimensional thermo-mechanical welding process simulation and obtaining the critical buckling stress and the buckling mode with a three-dimensional eigenvalue analysis sequentially. Tsai et al. 0924-0136/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.jmatprotec.2012.03.015