以某型动力集中式动车组车体牵引梁为例,在拓扑优化时,以牵引梁的质量减小为约束条件,寻求柔度最小时的材料分布,重构牵引梁的结构形状;在几何尺寸优化时,以牵引梁的板厚减小和符合安全条件为约束条件,寻求牵引梁质量最小时的板厚,从而...以某型动力集中式动车组车体牵引梁为例,在拓扑优化时,以牵引梁的质量减小为约束条件,寻求柔度最小时的材料分布,重构牵引梁的结构形状;在几何尺寸优化时,以牵引梁的板厚减小和符合安全条件为约束条件,寻求牵引梁质量最小时的板厚,从而进行牵引梁在满足规范安全要求下最大程度地一体化减重优化设计;基于拓扑优化和几何尺寸优化,选择2种不同的牵引梁优化结构,分别选用常用材料Q345和Q460进行减重和应力对比,并将减重更多、选用材料与初始设计材料Q460相同的优化后牵引梁代入整车模型中,进行静强度和疲劳强度校核。结果表明:牵引梁前端的长度和弧形板的弧度是牵引梁优化设计的主要内容,增加前端的长度有利于结构的传力;进行一体化减重设计后的结构,较初始设计时减重最多可达50.9%,具有明显的减重效果,且减重优化后牵引梁Mises应力均满足要求;优化后的牵引梁结构满足BS EN 12663-1—2010和TB∕T 3548—2019标准规定的静强度和疲劳强度要求。展开更多
An integrated simulation of powder effects on particle temperature and microstructural evolution in laser directed energy deposition additive manufacturing process was carried out.The spatial distribution of the flyin...An integrated simulation of powder effects on particle temperature and microstructural evolution in laser directed energy deposition additive manufacturing process was carried out.The spatial distribution of the flying powder particles was simulated by the discrete element method to calculate the energy for the flying powder particles under the laser−particle interaction with electromagnetic wave analysis.Combined with the phase field method,the influence of particle size on the microstructural evolution was studied.The microstructural evolution is validated through comparison with experimental observation.Results indicate that the narrow particle size distribution is beneficial to obtaining a more uniform temperature distribution on the deposited layers and forming smaller equiaxed grains near the side surfaces of the sample.Appropriate powder particle size is beneficial to the conversion of the electromagnetic energy into heat.Particles with small size are recommended to form equiaxed grains and to improve product quality.Appropriate powder flow rate improves the laser energy efficiency,and higher powder flow rate leads to more uniform equiaxed grains on both sides of the cross-section.展开更多
文摘以某型动力集中式动车组车体牵引梁为例,在拓扑优化时,以牵引梁的质量减小为约束条件,寻求柔度最小时的材料分布,重构牵引梁的结构形状;在几何尺寸优化时,以牵引梁的板厚减小和符合安全条件为约束条件,寻求牵引梁质量最小时的板厚,从而进行牵引梁在满足规范安全要求下最大程度地一体化减重优化设计;基于拓扑优化和几何尺寸优化,选择2种不同的牵引梁优化结构,分别选用常用材料Q345和Q460进行减重和应力对比,并将减重更多、选用材料与初始设计材料Q460相同的优化后牵引梁代入整车模型中,进行静强度和疲劳强度校核。结果表明:牵引梁前端的长度和弧形板的弧度是牵引梁优化设计的主要内容,增加前端的长度有利于结构的传力;进行一体化减重设计后的结构,较初始设计时减重最多可达50.9%,具有明显的减重效果,且减重优化后牵引梁Mises应力均满足要求;优化后的牵引梁结构满足BS EN 12663-1—2010和TB∕T 3548—2019标准规定的静强度和疲劳强度要求。
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(No.11572074)the Liaoning Provincial Natural Science Foundation,China(No.2019-KF-05-07)。
文摘An integrated simulation of powder effects on particle temperature and microstructural evolution in laser directed energy deposition additive manufacturing process was carried out.The spatial distribution of the flying powder particles was simulated by the discrete element method to calculate the energy for the flying powder particles under the laser−particle interaction with electromagnetic wave analysis.Combined with the phase field method,the influence of particle size on the microstructural evolution was studied.The microstructural evolution is validated through comparison with experimental observation.Results indicate that the narrow particle size distribution is beneficial to obtaining a more uniform temperature distribution on the deposited layers and forming smaller equiaxed grains near the side surfaces of the sample.Appropriate powder particle size is beneficial to the conversion of the electromagnetic energy into heat.Particles with small size are recommended to form equiaxed grains and to improve product quality.Appropriate powder flow rate improves the laser energy efficiency,and higher powder flow rate leads to more uniform equiaxed grains on both sides of the cross-section.
