Simulation Study On Flexible Forming Process Of Stiffened Plate

With continuous development of modern industrial technology, lightweight, high-performance structures are widely used in various fields. In thelong run, thinner and lighter will be the inevitable trend of the development ofengineering structures. Stiffened plate structure is a kind of commonlightweight structures in the fields of shipbuilding, aerospace, high-speedtrains manufacture and other projects, which can reduce the weight and ensurethe reliability and durability of the structure. However, the forming process ofthis kind of structures is more complicated than the plates without thestiffeners. Although the forming process now available for the structures couldmeet the requirements in aspects of forming precision and service life, therestill remains several insoluble problems, such as high requirements ofmaterials and equipments, high consumption of energy and production costsand strong dependence on the experience of the workers. Therefore, the needfor researching and developing new processes for the forming of the stiffenedplate structures is urgent.Multi-point forming technology is an advanced flexible forming processwith low production costs, high productivity, which is more used for smallbatch production of sheet metals with complex structures. It is clear that applying multi-point forming technology to stiffened plates forming couldcover the shortages in the current forming methods, which provides new ideasin this field. In this paper, the forming process of stiffened plates employingthe multi-point forming technology is simulated through the finite elementanalysis software ABAQUS. The researches mainly focus on the influences ofthe dimensions of the stiffeners and the adjustments of the punches on theforming results. The main contents and conclusions are summarized asfollows:1. The general steps of the finite element solution were explored and thedifferences between the explicit and the implicit algorithms were discussed.The FE models were built and the related elements selection, meshing andboundary conditions were described in details, which laid the foundation forthe subsequent numerical simulation studies.2. Multi-point stamp forming of the stiffened plates was explored deeply.The studies showed that the stiffener would impact the formed parts differentlyin different directions. When the height or width was increased, the stressconcentration would appear in the junctions of the stiffener and the plate; thesheet metal wrinkled at the center of the edge in OZ direction.3. The impacts of the adjustments of the punches on the forming precisionwere explored. The results showed that adjustments of the punches couldimpact the forming precision obviously and the forming errors came mainlyfrom the non-contact region; the improved model could reduce the errors. 4. Multi-point stretch forming of the stiffened plates was explored deeply.The results show that the stress distribution would not vary obviously whenthe height or width of the stiffeners was increased, but there would be crosssection distortion in the middle of the plates. By comparing the two aboveforming processes, we could find that the multi-point stretch forming issuitable for the forming of small-sized stiffened plates and it was cost-effectiveto employ the multi-point section forming for the big-sized stiffened plates.5. Inward bending of the stiffened plates through the multi-point stretchforming was explored deeply. The results showed that the adjustments of thepunches would influence the forming precision significantly. To choose theadjustments reasonably could avoid the defects and the get formed parts withsmall errors.