Papers by Author: J.R. Fan

Abstract: Laser peen forming is an emerging novel process of metal plate bending, which uses laser-induced shock wave pressure to generate an unbalanced residual stress field in the target, the moment of the residual stress causes metal plate to develop plastic bending deformation. The mechanism of laser shock induced residual stress was introduced firstly, then the deforming process of metal plate induced by residual stresses was discussed and the depth of the residual compressive stress was proposed. Effects of processing parameters on the residual stress distribution and plate bending deformation were numerical analyzed. The results indicated that the bending deformation of sheet was relative to laser peening numbers, peening coverage and thickness of plate, the magnitude and distribution of residual stresses could be precisely controlled by adjusting laser processing parameters.

Abstract: After the mechanisms of laser peen forming (LPF) were analyzed, the effect of sheet metal’s thickness on LPF was discussed in theory. The analysis model that residual stresses brought sheet bending was established, and the relationship between thickness and arc height of sheet metal was obtained. The process of laser shock wave loading during LPF was modeled, and then the residual stresses and deformation of the peened sheet were simulated by ABAQUS software. The results indicated that LPF use bending moments caused by residual stress to induce deformation, which was agreed with the theory analysis. The curvature of sheet metal induced by LPF decreased as the thickness increased, the arc height formed by bending was inversely proportional to thickness square of sheet metal on the whole. This research also has significance for the control of LPF and the investigation of further experiment

Abstract: As a new fabrication technique based on rapid prototyping, vacuum casting process can be especially used in the stage of products development. In this paper, a self-designed and made silicone mould was used to study process of vacuum casting panel part. ProCAST software was adopted to analyze the melt flowing behavior and effects of processing parameters. The key vacuum casting parameters, such as mould temperature, melt temperature, degree of vacuum and coefficient of heat transfer, on the effects of the filling rate of polymer melt were emphasized to be numerical studied. The results indicate that mould temperature and coefficient of heat transfer have the most important influence on quality of the formed panel.

Abstract: Laser shot peening (LSP) has recently received more and more attention as a viable laser processing technology, since it can obtain the desirable residual compressive stress to improve fatigue life of the material by precisely controlling laser parameters. The purpose of this paper is mainly to explore the optimal residual compressive stress in the surface layer during LSP by statistical optimization algorithm. Based on the finite element analysis software ANSYS, Multi-island Genetic Algorithm (MIGA) is adopted to find the best solution of design requirements, the control parameters are laser pulse energy and spot diameter, while the aim parameters are residual compressive stress and deformation values, respectively. The results indicate that the optimal residual compressive stress obtained by integrated optimization technique can significantly improve the mechanical properties of the target after LSP. It provides a guiding importance for parameters optimization in future experimental research and practical application.