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ORIGINAL ARTIC LE Dynamic analysis on laser forming of square metal sheet to spherical dome Lijun Yang & Maolu Wang & Yang Wang & Yanbin Chen Received: 19 October 2009 /Accepted: 19 March 2010 /Published online: 14 April 2010 # Springer-Verlag London Limited 2010 Abstract La ser forming (LF) is a new di e- les s formi ng tec hniq ue that employs the energy from a laser bea m to modify and adjust the curvature of sheet metals. In order to advanc e the LF process fur ther for rea list ic app lica tion industr y , it is necessa ry to conside r lar ge scale three- dimensional laser forming (3DLF). The main problem of 3DLF is the unde rst andin g of the mechanism and the plann ing of laser scanning strategy . This paper illustra tes the temperature field, stress – strain field, and deformation field in the process of 3DLF of square sheet to spherical dome wit h spi der -li nes strate gy wit h a finite element meth od (FEM). The explic it dyn amic integr al is use d in the work presented in the paper rather than implicit method for improvi ng the compu tational efficienc y and accuracy . The FEM results showed that the inner stress induced by the laser beam pr opagate s through the sheet as a stress wave, and the the rmal str ess and the stress wave in the she et are the main influence factors in 3DLF . Also , the FEM results have been verified against experimental data, and a rea sonable corre lati on has been found. The wor k showed in the paper would be beneficial of the parameter optimization of laser scanning strategy and the control of the formed precision of the sheet in 3DLF. Keywords Laser forming (LF) . Spheric al dome . Explicit dynami c analys is . Temperature field . Stress . Strain 1 Introduction Laser forming (LF) is a non-contact and die-less forming technique of producing bending, spatial forming, modify- ing, and adjusting the curvature of the metallic and non- metallic sheet by using the controlled laser beam energy. It is derived from the flame forming in the 1980s. The process is achieved by inducing the thermal stress into a sample by defocused laser beam and without melting in the irradiation sur face . The se str esse s ind uce the inte rna l ela stic – plastic strains , bendin g or shorte ning the workp ieces depending on the active mechanism. LF process has significant value to industr ies that previo usly relied on expensive stamping dies and pre sses for pro toty pe evaluations. Aero spa ce, ship - building, microelectronics, and automotive industries have shown interests in this forming technique. LF can produce metallic, predetermined shapes with minimal distortion. In contras t with convention al formin g techn iques, this method require s no mec hanical con tact and hence offe rs many advanta ges of proc ess flexibil ity ass ocia ted with other manufac turi ng tec hni ques. The re are lot s of adv anta ges wit h LF in engineering compar ed wit h oth er for ming techniq ues [1, 2]. The process of LF has been intensively investigated in the last 20 years. A great deal of work has been carried out on LF in straight-line scanning. The results show that some regularities on two-dimensional (2D) sheet bending angles have been gained in a number of materials [3 – 5]. Esp ecia lly , the underl ying forming mec hanisms and the var iety of pos sibl e app lica tions were ana lyze d and dis - cussed in detail. Howev er , in or de r to advance the LF L. Yang (*) : Y. Chen School of Material Science and Engineering, Harbin Institute of Technology, Harbi n 150001 , People ’s Republic of China e-mail: [email protected] L. Yang : M. Wang : Y. Wang School of Mechatr onics Enginee ring, Harbin Institute of Technology, Harbin 150001, People ’s Republic of China Int J Adv Manuf Technol (2010) 51:519 – 539 DOI 10.1007/s00170-010-2636-0
