Numerical Simulation And Experimental Research On Flexible Incremental Forming Technology Of Marine Sheet

Luxury cruise ship hull plate mostly composed of complex space curved plate,and the forming process of curved sheet metal,as one of the key technologies of ship building will affect the development of shipbuilding technology in China.Compared to the traditional shipboard forming in low efficiency,poor accuracy and other shortcomings,a flexible incremental forming technology of marine sheet is proposed by numerical simulation and experiment.The forming process of typical single and double curvature plates are researched in this paper.The main contents of this research are shown as follows:1.Based on the characteristic of large-scale shipboard local forming,with Hill's yielding criterion,exponential strain hardening law as well as plane strain condition,a 3D finite-element models are proposed in this paper for researching the flexible incremental forming technology.2.The theories of local bending and rolling forming in flexible incremental forming process are analyzed in this paper.Through the analysis of the parameters of the orthogonal bending test,it found the pressing amount of the punching has the most significant influence on the bending radius of the plate,and the radius of the punch is the least important,and the relationship between the punch reduction,the die clearance and the bending radius is approximately linear.Through the rolling comparative experimental study,it found that the roll bending radius decreases with roll pressure increases,and the rate of change is also gradually reduced.3.The adjustable structure multi-pass local bending mold is designed in the study.Taking multi-pass bending test of single curvature plate as the research object,the validity and accuracy of the numerical simulation results are explored and analyzed,the final simulation and experimental results are controlled within 5%,and based on this,the multi-pass local bending is used to finish the forming of sailboard.4.Considering the forming efficiency and the forming quality of the shipboard,the parameter optimization of the multi-pass local bending is proposed.Taking forming pass and processing sequence as research point,the paper compares the bending radius of curvature under different processing pass as well as the symmetrical loading,linear loading and sheet loading condition.Under the assumption of equal transformation,the hyperbolic accuracy of the sailboard is optimized,and the dimensional accuracy of the center curvature is improved by the point pressure forming.