Papers by Author: Yin Fang Jiang

Abstract: Laser shock processing is a technique similar to shot peening that imparts compressive residual stresses in materials for improved fatigue resistance. Finite element analysis techniques have been applied to predict the residual stresses from Laser shock processing. The purpose of this paper is to investigate of the different sheet thickness interactions on the stress distribution during the laser shock processing of 7050-T7451 aluminum alloy by using the finite element software. The results indicate that the sheet thickness has little effects on the compression stress in the depth of sheet, but great impacts on the reserve side.

Abstract: With more and more attention to the technology of tailor welded blanks (TWBs), it is vital to study the springback of TWBs. In this paper, the springback law of parallel and perpendicular to the weld of TWBs hyperboloid shallow shell affected by blank holder force, punch string height, and the difference of blank thickness was researched by finite element software. The results show that: by means of drawing and trimming, the springback of TWBs can be reduced, and the curvature of TWBs is less parallel to the weld, but the curvature is larger perpendicular to the weld. The effect of blank holder force on the trimming springback is relatively small in the range of experimental date. With the punch string height increasing, the drawing and the trimming springback are both increased firstly and then gradually decreased perpendicular to the weld, and the drawing and the trimming springback are both decreased parallel to the welding. And perpendicular to the weld, with the increase of the quadratic difference of thickness, the drawing springback of the thinner side is gradully decreased, and the drawing springback of the thicker side is gradually increased, after trimming, the springback of the thinner and the thicker side are both less than the drawing springback, and parallel to the weld, the drawing and the trimming springback are decreased firstly and then increased with the increase of the quadratic difference of thickness.

Abstract: It is very important that the shape and size of the slab is designed for forging quality in casting-forging coordinate process. The converse design of aluminum alloy connecting-rod slab is investigated. First, the initial structure of the connecting rod slab is designed, then its forging process is simulated by the software DEFORM, modifying and optimizing the initial structure according to the problems in the analysis, and the slab's casting process is simulated. The converse design reduces the blindness in the slab design process, shorts the designed cycle, and ensures the consistency between slab and the final forging better.

Abstract: Laser shock forming in oblique angle of metal sheet is involved due to the complexity of parts profile and multiple points forming by laser shock. The influence of incident laser angle and constraint pore diameter of the mold on the forming characteristics of metal sheet is investigated according to the experiment and finite element simulation. The results show there is a horizontal deviating deformation in the place of the maximum deformation in oblique shock, as the incident angle deviating vertical direction increases, the vertical displacement amount decreases nonlinearly and the horizontal deviating amount increases gradually; and the vertical displacement amount of sheet increases with the increase of the mold constraint pore diameter in a certain range, but decreases above this certain range. The metal sheet fractures when shock times increase, the extended crack is paralleled to roll direction of metal sheet in vertical angle shocking, but the extended cracks in oblique shocking, some is paralleled to roll direction of metal sheet, another is vertical to this direction. The forming characteristics of metal sheet under laser shocking in oblique angle is very important, which provides evidence for the large area precision forming and parameters optimization by laser shock forming.