CONTROL OF RESIDUAL STRESS FOR LASER AIDED DIRECT METAL DEPOSITION BASED ON DIMENSIONAL ANALYSIS
基于量纲分析的激光直接成形残余应力控制

In the process of laser aided direct metal deposition (DMD), the control of thermal-induced residual stress is very difficult, because the stress is affected by many parameters including geometrical dimensions, material properties and process parameters. In this paper, dimensional analysis is employed to extract key dimensionless parameters of geometry, heat transfer and thermal deformation. In addition, a 3D transient FEA model is proposed to study the effects of these key dimensionless parameters on the residual stress. It is shown that the residual stress can be controlled by employing materials with relatively small thermal expansion coefficient or small yield stress. Furthermore, the residual stress can be reduced by decreasing heat loss, increasing laser power, especially, by increasing preheat temperature.