Light-weight Design Of Autobody Thin-Wall Structures Using Additive Manufacturing

In recent years additive manufacturing (3D printing) have been widely used in custom-tailored design and production, due to its strong ability in fabricating arbitrarily geometries. It is also applied in the field of automobile styling design, which rapidly prototypes concept designs. Compared with the conventional methods of proportionally scaling clay model making,3D printing technology can greatly shortened the product development cycle and improve accuracy of the model.Although the printing method of autobody thin-wall structures using uniform thickness method is simple and easy to operate, but it has two drawbacks. Firstly, the select of thin-wall structure thickness based on experience, in order to increase the local strength, the overall-thicken strategy was taken, which caused the unreasonable use of materials. Secondly, social modeling problems are appeared along with the popularization of 3D printing technology. Due to the lack of structural design experience, the failure of the printing model is often happened which is caused by insufficient mechanical property. Therefore, how lightweight the thin-wall structure of Autobody under accuracy appearance of model is the key points of my researchWe propose two methods to tackle the problems as follows:(1) Aiming at the problem of lightweight modeling for thin-wall structure of autobody models, we propose a heat diffusion method. Firstly, obtaining an initial model whose thickness corresponds to the simulated value in the heat field that is used to simulate the stress distribution. Secondly, use numerical simulating,3D printing and the engineering validation to optimize the thickness of the model. Finally the model which meets the performance requirements was obtained. Compared with the traditional model of uniform thickness, the average weight reduction of the optimized model is 30%. Meanwhile, the printing time and material costs were greatly shortened, proving the proposed method is effective and efficient.(2) Based on multi-cellular reinforcing structure applied in thin-wall structures, firstly, we use multi-criteria decision making method to compare the mechanical properties of three kinds of multi-cell reinforced structure under bending and torsional loading conditions. Secondly, the size of selected hexagonal structure under the target of smallest compliance and volume are optimized, and Pareto optimal solution set is obtained. Finally, the multi-cellular structure and uniform thickness structure under bending and torsional loading conditions are analyzed respectively. The results show that the weight is decreased around 17% and 20%, respectively, under bending and torsional loading conditions, which verifies the application of multi-cell reinforced structures to lightweight design and 3D printing.In summary, we proposed two optimization methods, for the light-weight modeling of thin-walled structures, combined with the technical superiority of adaptive manufacturing technology, to achieve the unified surface-structure for 3D printing automobile stylistic prototype.