Finite Element Analysis of Residual Stress in TC4 Alloy Stiffened Plate Produced by Laser Additive Manufacturing

Abstract

With the development of navigation and aerospace engineering, higher requirements have been put forward for the weight reduction of structures, so stiffened plate structures have been more and more widely used. Through laser additive manufacturing technology, it is possible to significantly improve the performance of stiffened plate while achieving low-cost and rapid production of stiffened plate. However, due to the effect of temperature gradient in the forming process, the residual stress of the stiffened plate is inevitable, which directly affects the forming accuracy and performance of the plates. In this article, five thermomechanical coupling models were established based on the finite element method to simulate the residual stress of stiffened plates, and the models have been verified through experiments. The results show that ribs have an “adsorption” effect on the stress on the flat plate. After reinforcement, the maximum stress on the plate increases, but the stress distribution area becomes smaller. The average maximum residual stress on the plate when the rib is perpendicular to the scanning path of the plate is greater than when the rib is parallel to the scanning path of the plate. Adding chamfers can significantly reduce the residual stress in the contact area between the ribs and the flat plate. The research in this article is of great significance for the structure design and residual stress control of titanium alloy stiffened plates made by additive manufacturing.