Experimental investigation of a gliding discharge plasma jet igniter

Relight of jet engines at high altitude is difficult due to the relatively low pressure and temperature of inlet air. The penetration of initial flame kernel affects the ignition probability in the turbine engine combustor greatly. In order to achieve successful ignition at high altitude, a deeper penetration of initial flame kernel should be generated. In this study, a Gliding Arc Plasma Jet Igniter(GAPJI) is designed to induce initial flame kernel with deeper penetration to achieve successful ...     

铝合金增材制造的发展现状与展望北大核心CSCD

铝合金增材制造凭借着材料自身的轻量化优势以及增材制造工艺在材料利用率和复杂结构制造方面的特点,在航天领域结构件的制造方面受到了广泛关注。本文针对铝合金增材制造在航天领域的应用,通过电弧熔丝、激光选区熔化以及激光送粉三个代表性工艺分析铝合金增材制造技术的研究现状及现存问题,并简要阐述了目前铝合金增材制造技术在航天领域的应用现状和未来的发展方向。     

智能制造技术在航天大型构件中的应用

智能制造是制造技术、系统工程、人工智能与网络技术等学科互相渗透、互相交织而形成的一门综合技术，可为高品质复杂零件制造提供新的解决方案，特别适应航天多品种、小批量生产的需要。本文分析了航天大型构件的生产制造现状，并列举了智能制造在航天构件领域应用的情况，分别从体系构架、工艺技术、制造装备、生产管理方面阐述了智能制造的实践应用。结合企业近年来的工作，从数字化的航天产品工艺设计和管理、面向航天复杂构件的智能化装备升级、全过程透明化的智能运营管控、航天智能焊接车间建设探索、数字孪生技术实现虚实融合等几个方面展开论述。     

Comparison study of ductile iron produced with Martian regolith harvested iron from ionic liquids and Bosch byproduct carbon for in-situ resource utilization versus commercially available 65-45-12 ductile iron

As researchers continue to study methods to facilitate long-term missions beyond low-Earth orbit, the ability to manufacture high-quality mechanical and structural components on the Lunar and Martian surfaces remains a crucial piece to the puzzle for a sustained presence. Due to the immense cost of sending supplies to extraterrestrial bodies, in-situ resource utilization (ISRU) methods are critical for the success and feasibility of these habitation missions. Ionic liquids (ILs) are currently being studied at NASA’s Marshall Space Flight Center (MSFC) to harvest elemental metals from meteorites and regolith minerals. Additionally, the Bosch process is being explored as a life support system at MSFC for oxygen (O₂) regeneration, rendering a byproduct of elemental carbon (C). In this investigation, the viability of casting ductile iron (DI) using IL-sourced iron (IL-Fe) and Bosch C was studied given the range of applications and performance of DI as an as-cast alloy. Ingots were produced using commercial elements to simulate the use of IL-Fe with C sourced from the byproduct C of the Bosch process. Samples were cast and compared to commercially available 65–45-12 DI with phase transformation diagrams, microstructures, and hardness. Results showed that IL-sourced elements are a viable source of elemental alloying materials for a range of DI alloys, with some limitations.     

2219 铝合金单、双道焊接头性能分析

通过对比2219 铝合金单道氩弧焊和氦弧打底+氩弧盖面双道焊接头的常温及液氮温度拉伸性
能、显微硬度分布、单向拉伸过程的数字散斑测量(DIC)结果,发现在常、低温条件下双道焊接头的拉伸强度和
延伸率均比单道焊接头高10% ~20%,单道焊接头焊缝及热影响区内材料的显微硬度值相比母材的降低程度
比双道焊接头更为显著,其主要原因是单道焊接头的一次性热输入大于双道焊,材料受热影响更严重,焊漏高
度及形状的可控性更差。     

航空工业的智能制造体系和架构

智能制造包含智能制造技术和智能制造系统,是国际上公认的实现工业体系转型升级的新一代方法论,能够从根本上提升我国复杂产品的创新能力和研制水平,因此,正确理解、全面认识智能制造,对我国的经济发展、数字中国的建设具有极其重大的现实意义和历史意义.智能制造的基础是数字化,由于航空工业具有复杂性、可靠性、研制成本高的三高特征,因...     

激光熔化沉积15-5PH沉淀硬化不锈钢组织及拉伸性能

利用激光熔化沉积技术制备15-5PH沉淀硬化不锈钢板,利用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、电子探针(EPMA)技术,对沉积态组织进行分析,测试沉积态组织的室温拉伸性能。结果表明:激光熔化沉积15-5PH不锈钢沉积态组织由沿沉积增高方向贯穿多层外延生长的柱状晶组成,柱状晶内包含多个细长整齐排列的胞状树枝晶,枝晶内为马氏体组织,枝晶间为铁素体;沉积态组织中弥散分布大量细小的NbC析出相,尺寸12～20 nm;15-5PH不锈钢沉积态组织具有良好的力学性能,纵向抗拉强度和延伸率分别为1 128.5 MPa和14.0%,横向抗拉强度和延伸率分别为1 101 MPa和12.25%。     

Collaborative manufacturing technologies of structure shape and surface integrity for complex thin-walled components of aero-engine: Status,challenge and tendency

Presently, the service performance of new-generation high-tech equipment is directly affected by the manufacturing quality of complex thin-walled components. A high-efficiency and quality manufacturing of these complex thin-walled components creates a bottleneck that needs to be solved urgently in machinery manufacturing. To address this problem, the collaborative manufacturing of structure shape and surface integrity has emerged as a new process that can shorten processing cycles, improve machining qualities, and reduce costs. This paper summarises the research status on the material removal mechanism, precision control of structure shape, machined surface integrity control and intelligent process control technology of complex thin-walled components. Numerous solutions and technical approaches are then put forward to solve the critical problems in the high-performance manufacturing of complex thin-wall components. The development status, challenge and tendency of collaborative manufacturing technologies in the high-efficiency and quality manufacturing of complex thin-wall components is also discussed.     

穿孔泡沫夹层复合材料低速冲击性能试验研究

针对普通泡沫夹层复合材料层间性能较弱的问题，提出在泡沫上预先打孔的方法，在泡沫芯材中形成胶钉从而提高泡沫夹层材料的力学性能，并对穿孔泡沫夹层复合材料的低速冲击性能进行了研究。通过手糊和真空辅助成形工艺制备穿孔泡沫夹层复合材料试验件，对其进行不同能量的低速冲击试验，记录接触力、冲头位移和能量吸收率等力学响应，并采用目视检测和超声C扫无损检测两种方法确定冲击损伤的范围，探究胶钉密度、打孔深度和泡沫槽宽等变量对穿孔泡沫夹层复合材料低速冲击阻抗性能的影响。试验结果表明，随着冲击能量的增加，最大接触力、最大冲头位移和残余变形均增加，凹坑深度和内部损伤面积也增大，同时结构的能量吸收率也有所提高；适当地增加胶钉密度和泡沫槽宽能提高穿孔泡沫夹层材料的低速冲击阻抗性能，而泡沫孔深度对其冲击性能的影响较小。     

梦天实验舱初始轨道快速计算策略与分析

初始轨道是航天器入轨评价的关键判据，快速准确计算初始轨道可在入轨异常时为应急救生控制赢得时间。针对传统初始轨道计算方法时间与精度不能兼顾的问题，设计了初始轨道快速计算策略，根据运载火箭加速度变化率来判断舱箭分离时间，采用基于动力学约束的实时轨道滑动批处理方法累积超短弧分离后数据计算初始轨道，对利用各种数据源确定的多组初始轨道进行逻辑优选判断。通过梦天试验舱仿真数据验证表明:使用该策略计算初始轨道，可达到事后精密定轨同等精度，计算时间控制在1 min以内，时效性远超事后精密轨道确定方法。