Study On The Thermal-Mechanical Coupling Simulation Of Coaxial Powder Feeding Laser Additive Manufacturing Process

Laser additive manufacturing technology is a new manufacturing technology based on the principle of layered stacking.This technology has been applied in aerospace,automobile,ships,rail vehicles and biomedical fields to varying degrees because it can greatly reduce the manufacturing difficulty of complex parts and quickly repair parts damage.However,due to the extremely complex interaction between laser and metal materials in additive manufacturing,it is difficult to accurately measure the stress value caused by temperature change only by experimental methods.Therefore,it is of great significance to use computer simulation method to explore the distribution rules of temperature field and stress field and to analyze the influence of process parameters on temperature field and stress field under different conditions.In this paper,based on the sequential thermodynamic coupling method,the evolution and distribution of thermodynamic quantities in laser additive manufacturing process of GH4169 superalloy were simulated by ABAQUS software.The main research contents are as follows:Firstly,the single channel and single layer coaxial powder feeding laser additive manufacturing finite element model is established.The correctness and rationality of the numerical simulation scheme are verified by comparing the size of the molten pool of numerical simulation and experiment.On this basis,the temperature history of the joint between substrate and sedimentary layer sides is discussed,the distribution rules of transverse and longitudinal temperature gradient,the stress evolution in the additive process and the residual stress distribution after cooling are discussed.Secondly,the influence of laser scanning speed and substrate preheating on the temperature history change at the joint between the substrate and the sediment layer is analyzed.The influence on transverse and longitudinal temperature gradient is analyzed.The influence on stress evolution in addition process and residual stress distribution after cooling is analyzed.Finally,based on the numerical simulation results of single channel and single layer,the difference between the numerical simulation results of square and arc sediments is analyzed,and the results show that the residual stress is not affected by the shape of different sediments.On this basis,a single-channel multilayer finite element model is established.The influence of temperature and stress fields distribution in the process of single-channel multilayer additive is discussed.The influence of different laser scanning directions of the fourth layer on temperature and stress fields are discussed.The finite element model established in this paper can reasonably and effectively simulate the distribution rules of temperature field and stress field in laser additive manufacturing process under different process parameters,which has certain reference value for experimental process exploration and helps promote the development of laser additive manufacturing research.