Research On The Local Surface Self-nanocrystallization To Increase The Strength Of Metal Plate

Metal plate structure is widely used in engineering. The problem of safety for this kind of structure has been concerned for a long time. The strength of the plate is closely related to the safety of the structure. Reducing the weight of the structure and increasing the intensity of the structure have always been the goal that people pursue. Generally speaking, the structure of thin plate is prone to deformation, and its deformation is controlled by boundary conditions and external loads. When the plate structure is subjected to external loads, the stress distribution is prone to the inhomogeneity and strain localization. Often in these local areas, the plate is more prone to damage. The local area of the plate is an effective means of increasing the intensity. The tensile strength and bending strength can be increased by replacing the material or changing the boundary conditions and adding additional structure. However, this will change the structure layout, we need to design and check again. And the layout also changes the appearance, and impacts the aesthetic. In this paper, we try to study a method and technology that can not change the appearance of material and structure, but also enhance the structural strength. The characteristic of this method is to use the local surface nanotechnology on the thin plate materials. With the aid of local surface nanotechnology to change the mechanical properties of materials and structures, we can not only reach the structural design requirements of the thin plate under the load such as tensile or bending, but also realize the purpose of increasing the overall intensity of structure and reducing the local displacement. This can play the biggest effect of material and structure. In this way, a new method for controlling the deformation of the thin plate under the load and the solution of increasing the local characteristic of the structure is proposed. In this paper, the finite element analysis is used to simulate the problem and get the following results.1. A local surface nanostructure layout method for the overall tensile and flexural strength of the rectangular thin plate is proposed. When the thin plate is stretched and bent, by optimizing design of the main bearing region of the thin plate with local surface nanocrystallization. We found that the total displacement of it is greatly reduced after nano—processing. And the regional distribution of local nano layout in the stress concentration area or the stress of the larger regional effect is more obvious. The influence of the size of the load and the displacement of the thin plate is analyzed,too. The results show that the local surface nano technology can improve the tensile stiffness and bending rigidity, the external load and the constraints also have a great influence on the deformation of the thin plate.2. In view of the stress concentration of metal plate, a local surface nanostructure layout scheme is proposed. Considering various shapes and multiple stress concentrations, local surface of the stress concentration region in the thin plate is nanocrystallized. The results show that under the same load condition, the maximum displacement of the sheet is obviously decreased. It also show that the overall surface treatment of the thin plate is not the best way. The reasonable. local surface nano distribution can also be realized not only to decrease the stress concentration coefficient, but also to decrease the total displacement. It can be seen that the local surface nano layout can meet the design requirements, and can reduce the difficulty of the process and save the cost. The results show that the surface of the nano region can be reduced by 80%.. This can optimize the nano processing technology.3. Considering the strength of the metal thin plate with holes in it, a local surface nanostructure layout method is presented. According to the special characteristics of this kind of thin plate, a method of covering the hole near the hole and the method of local nanometer degree is proposed. Numerical simulation of thin plate with rectangular holes is carried out. The results show that the nano-based method can decrease the displacement of the thin plate. The effect of this method is more pronounced for asymmetric void structures. This method can be applied to the problem of enhancing the strength of the thin plate. And also provides an effective path for solving similar problems.