Numerical Simulation And Forming Law Of Sheet Metal Incremental Forming

Sheet metal forming parts have been widely used in various industries, the traditional sheet metal forming process requires molds, which leads to a long development cycle and high manufacturing cost of one piece. Incremental forming is a novel kind of die-less forming technology, it is characterized by highly process flexible,low cost and short processing cycle, etc. It provides a competitive alternative for fabricating multi varieties, small batch and customized functional sheet product. Therefore, it has a wide application prospect.Process parameters choice and tool-path design of incremental forming is the critical to fulfill quality requirements, the influences of process parameters and tool-path design to forming formability is one of mainly research points in this thesis. The muti-step incremental forming is a key technology to forming steep angle part, the material deformation law of muti-step incremental forming is another explored issue. Main research contents and results are shown as follows:Firstly, parts thickness varies rules and the state of stress and strain during incremental forming are studied based on elastic-plastic theory, and the control principles are discussed.Secondly, the FEM model is established based on ANSYS/LS-DYNA software. The ellipsoid, truncated cone and pyramid parts are respectively simulate, the simulation results have verified that plane strain is the primary deformation mode. The experiments are supposed to verify the FEM model,.the simulated results are in good agreement with experiment results on inclined thickness and accuracy.Thirdly, the influences of incremental depth, tool diameter and motion mode of trajectory are studied based verified FEM model. The results shows that incremental depth is smaller, maximum thickness reduction ratio decrease, with tool diameter increasing, stress concentration is slowed down, thickness uniformity and shape twist is improved obviously by inverse tool-path direction between two layers.Finally, material deformation law of muti-step incremental forming is studied by numerical simulation and experiment, material flow, strain and thickness change are analyzed. The results indicate that the obvious radial flow and the second principle strain are discovered, and both increasing with the steps. The more steps, the lager minimize wall thickness value, and more thickness uniformity, and the influence of forming angle to thickness uniformity increase.