航空发动机试验测试技术发展探讨

强调了航空发动机试验测试技术在发动机研制过程中的重要性。简述了航空发动机试验测试技术的特点及国内外发展现状,分析了其试验测试技术发展需求,提出了发展设想。为适应新1代航空发动机研制的需求,必须积极推进其试验测试技术的快速发展,应及时开展其研制试验所需测试仪器的研究和开发,组织开展其试验测试技术研究,加强专业间交流和协同,进一步提高试验测试结果的准确度,建立和完善试验测试技术标准规范。     

复合材料修理结构的缺陷特征与超声信号

研究了热补仪修理复合材料层压板结构的缺陷特征。金相显微分析结果表明,当修补层数为2层时,样品没有任何缺陷产生;当修补层数增加到4层时,修补层内出现气孔缺陷;当修补层数增加到6层时,除了修补层内出现大量气孔缺陷以外,胶膜层也出现气孔,导致弱粘接/脱粘缺陷的产生。超声检测的结果与金相显微分析一致,很好地再现了上述缺陷。     

压缩比对金属橡胶结构和压缩力学性能影响

加工了具有相同尺寸和质量的多个金属橡胶,而各金属橡胶对应不同高度的毛坯,引入"压缩比"概念,即毛坯高度和模压后金属橡胶成品高度之比,分析压缩比对金属橡胶结构和力学特性的影响.准静态试验结果表明:压缩比会显著的影响金属橡胶的表观结构以及各向异性力学特性,压缩比较大,到达5~6时,金属橡胶表观的螺旋丝呈现有序的竖立堆积状,同时成型方向刚度偏小;而压缩为2时,成型方向刚度很大,非成型方向刚度相比于其余压缩比试件明显偏小.试验结果表明:在金属橡胶的加工和设计过程中,需要考虑压缩比对性能的影响.      

飞机紧固件孔壁裂纹的涡流无损检测

在分析涡流无损检测技术工作原理的基础上,阐述涡流无损检测技术检测飞机紧固件孔壁裂纹的方法步骤,并对飞机紧固件孔壁裂纹的修理工作提出相关建议,以期为后续工作提供参考与借鉴。     

铝合金框的超声波检测

阐述了铝合金框零件的超声波检测方法;分析了影响检测的因素,并提出了解决的办法。     

航空发动机部件虚拟装配及数字化检测技术

虚拟装配与数字化检测技术是航空发动机制造中的先进技术,应用在发动机部件装配及检测中能起到事半功倍的作用。为满足某航空发动机新型喷管的研制需要,以新型喷管为载体,进行了虚拟装配及数字化检测技术研究。结果表明,虚拟装配技术的运用,避免了不必要的返工和浪费,能缩短装配周期,节省研制成本,加快研制进度;而数字化检测技术的运用,使装配质量有了大幅提升,使发动机可靠性得到保障。     

Integration of In-Situ Resource Utilization into lunar/Mars exploration through field analogs

The ability to extract and process resources at the site of exploration into useful products such as propellants, life support and power system consumables, and radiation and rocket exhaust plume debris shielding, known as In-Situ Resource Utilization or ISRU, has the potential to significantly reduce the launch mass, risk, and cost of robotic and human exploration of space. The incorporation of ISRU into missions can also significantly influence technology selection and system development in other areas such as power, life support, and propulsion. For example, the ability to extract or produce large amounts of oxygen and/or water in-situ could minimize the need to completely close life support air and water processing system cycles, change thermal and radiation protection of habitats, and influence propellant selection for ascent vehicles and surface propulsive hoppers. While concepts and even laboratory work on evaluating and developing ISRU techniques such as oxygen extraction from lunar regolith have been going on since before the Apollo 11 Moon landing, no ISRU system has ever flown in space, and only recently have ISRU technologies been developed at a scale and at a system level that is relevant to actual robotic and human mission applications. Because ISRU hardware and systems have never been demonstrated or utilized before on robotic or human missions, architecture and mission planners and surface system hardware developers are hesitant to rely on ISRU products and services that are critical to mission and system implementation success. To build confidence in ISRU systems for future missions and assess how ISRU systems can best influence and integrate with other surface system elements, NASA, with international partners, are performing analog field tests to understand how to take advantage of ISRU capabilities and benefits with the minimum of risk associated with introducing this game-changing approach to exploration. This paper will describe and review the results of four analog field tests (Moses Lake in 6/08, Mauna Kea in 11/08, Flagstaff in 9/09, and Mauna Kea in 1/10) that have begun the process of integrating ISRU into robotic and human exploration systems and missions, and propose future ISRU-related analog field test activities that can be performed in collaboration with non-US space agencies.     

快变换超音频直流脉冲GTAW电弧行为

基于超音频直流脉冲钨极氩弧焊(GTAW,Gas Tungsten Arc Welding)电源输出脉冲电流沿变化率di/dt≥50A/μs的超音频直流脉冲方波电流,将其用于0Cr18Ni9Ti奥氏体不锈钢GTAW焊接过程,研究分析了焊接电弧特性、电弧力及焊缝熔透特性.结果表明:超音频直流脉冲方波电流参数对电弧电学特性、形态及电弧力产生显著影响,与常规直流GTAW相比,快变换超音频直流脉冲GTAW电弧表现出明显的收缩效应,焊缝熔深在一定范围增大,熔宽减小,平均电弧力大幅增长,焊接效率提高.     

脱粘尺寸对复合材料单加筋板压缩性能的影响

为确定脱粘缺陷尺寸对轴压载荷下复合材料单加筋板屈曲和后屈曲特性的影响,对4组含不同尺寸脱粘缺陷的工型加筋板进行了试验和数值模拟研究。试验中通过应变测量和超声C扫描等技术手段对试验件的屈曲及后屈曲过程中的变形和缺陷扩展情况进行了监测。基于ABAQUS软件建立了有限元分析（FEA）模型,采用LaRC03准则对复合材料层内损伤进行判定,采用胶层单元对界面脱粘损伤进行模拟,以几何扰动的形式引入失稳波形,利用FEA模型对试验件的屈曲和后屈曲过程进行了模拟。模拟结果与试验结果吻合较好,根据研究结果对试验件的失效过程和脱粘缺陷扩展机理进行了分析与探讨。研究表明,预制脱粘缺陷尺寸大小对试验件屈曲和后屈曲特性影响较大,对最终破坏模式影响不大。脱粘尺寸的增大会导致试验件承载能力的大幅降低,在复合材料加筋结构损伤容限设计中需要着重考虑。