圆环构件增材制造残余应力模拟及尺寸效应分析  

Numerical modeling of residual stress in circular component in additive manufacturing and scaling effect analysis

作　　者：葛芃 张昭[1,2] 张少颜 赵国忠[1] GE Peng;ZHANG Zhao;ZHANG Shao-yan;ZHAO Guo-zhong(Department of Engineering Mechanics,Dalian University of Technology,Dalian 116024,China;State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学工程力学系,辽宁大连116024 [2]大连理工大学工业装备结构分析国家重点实验室,辽宁大连116024

出　　处：《塑性工程学报》2019年第5期249-255,共7页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(11572074)

摘　　要：采用顺序热力耦合有限元模型对圆环构件激光沉积增材制造过程残余应力和残余变形进行数值模拟。在对直板激光沉积增材制造残余应力验证的基础上,对不同激光移动速度、不同尺寸环状构件激光沉积增材制造过程残余应力变化进行了系统的讨论研究。模拟结果表明,激光沉积增材制造后,环形构件残余变形以增材层径向向内弯曲和基板竖向向下弯曲为主;增材层残余应力依然以环向和竖向残余应力为主,最大拉伸残余应力接近材料屈服点。激光移动速度的减小将极大的影响增材层残余应力的分布,提高中间增材层内、外侧环向残余应力,并使得增材层径向向内弯曲量减小。在相同工艺下对不同尺寸环状构件进行激光沉积增材制造,环状构件截面内环向和纵向拉伸残余应力区域均将随构件尺寸的增大而增大,这与构件在经历多次热循环过程中的冷却速度有关。制造过程中可采取提高环境温度、降低冷却速率等方式降低大尺寸构件截面内拉伸残余应力,以提高激光沉积增材制造构件后期服役性能及安全性。The residual stress and residual deformation of circular component in laser deposited additive manufacturing( LDAM) was numerically simulated using transient coupled thermo-mechanical model. On the basis of verifying the residual stress of laser deposition additive manufacturing for straight plate,the variation of residual stress of circular component with different sizes and laser speeds in LDAM was systematically discussed and researched. The simulation results show that with LDAM,the residual deformation of circular component is mainly caused by the radial inward bending of the additive layer and the vertical downward bending of the substrate. The residual stress of the additive layer is mainly circumferential and vertical residual stress. The maximum tensile residual stress is close to the yield stress of deposited material. The distribution of residual stress is greatly affected by the decrease of laser speed,also the circumferential residual stress inside and outside of the middle additive layer increases and the radial inward bending value of the addictive layer increases. LDAM was carried out on circular component with different sizes under the same process. The zone of circumferential and vertical tensile residual stress in section of circular component increases with the increase of component size,which is related to the cooling rate of the component in the process of multiple thermal cycles. In order to improve the service performance and safety of LDAM components,the methods such as raising ambient temperature and reducing cooling rate are adopted to reduce the tensile residual stress in the section of large-size components.

关 键 词：尺寸效应 圆环构件 增材制造 残余应力 

分 类 号：TG156[金属学及工艺—热处理]