Ti6Al4V钛合金大进给铣削切削力与切削温度的试验研究

采用可转位涂层硬质合金刀具对Ti6Al4V钛合金进行了大进给铣削试验,研究分析了大进给铣削Ti6Al4V钛合金时每齿进给量、切削速度、轴向切深以及径向切深等切削参数对切削力和切削温度的影响。研究结果表明,随着每齿进给量和轴向切深的增加,切削力均呈现增大的趋势,而切削速度和径向切深对削力的影响并不明显;随着每齿进给量和切削速度的提高,切削温度亦呈现升高的趋势。     

捕捉激波的群速度控制方法

回顾及综述了群速度控制方法基本原理、发展过程及最新进展。群速度控制方法是通过控制色散误差以捕捉间断的一种数值方法。该方法通过在间断两侧采用不同色散类型的格式,将数值波的传播压制在间断附近,避免数值振荡向周围扩散,从而达到抑制数值振荡的效果。该方法主体上采用数值色散抑制振荡,实际使用中仅需补充较低水平的数值耗散就可将振荡压制在可接受的范围内。因而群速度控制格式的总体耗散水平较低,易于实现小尺度波的高分辨率捕捉,是复杂流动高分辨率数值模拟的有效方法。     

运输类飞机包含EWIS的区域安全性分析研究

为了解决运输类飞机EWIS设计过程中的安全性评估问题,针对包含EWIS的区域,提出了一种区域安全性分析方法。在对ARP4761标准的区域安全性分析和AC25-27的强化区域分析流程的基础上,考虑EWIS物理失效模式及失效对EWIS自身和区域内系统/设备的影响,给出了分析流程,为EWIS满足适航要求的设计提供技术参考。     

Cutting force prediction for circular end milling process

A deduced cutting force prediction model for circular end milling process is presented in this paper. Traditional researches on cutting force model usually focus on linear milling process which does not meet other cutting conditions, especially for circular milling process. This paper presents an improved cutting force model for circular end milling process based on the typical linear milling force model. The curvature effects of tool path on chip thickness as well as entry and exit angles are analyzed, and the cutting force model of linear milling process is then corrected to fit circular end milling processes. Instantaneous cutting forces during circular end milling process are predicted according to the proposed model. The deduced cutting force model can be used for both linear and circular end milling processes. Finally, circular end milling experiments with constant and variable radial depth were carried out to verify the availability of the proposed method. Experiment results show that measured results and simulated results corresponds well with each other.     

直升机复合材料构件检测与修理系统向设计与实现

介绍了直升机复合材料构件检修与修理系统的设计与实现,包括检测与修理系统硬件平台的搭建,复合材料湿法成形异型模具的设计制作、复合材料构件深度修理工艺的研编以及计算机辅助修理系统的开发四部分。本系统操作方便、功能实用．可快速进行直升机复合材料构件检测,提供合理的修理工艺和方法,有效管理其修理过程。     

基于AHP的民航维修系统评价方法研究

在民航维修系统评价指标体系的基础上．基于层次分析法（AHP）建立了民航维修系统AHP评价模型。从目标层、准则层和评价对象层三个方面构建了维修系统综合评价层次结构．阐述了相应评价参数的涵义并给出了计算方法,最后进行了相应的应用案例研究。     

飞机燃油系统健康管理体系研究

健康管理技术是提升高风险复杂技术装备安全性、可靠性的关键技术之一。本文以飞机燃油系统为对象．依据健康管理系统基本框架,构建了飞机燃油系统健康管理体系。在对其子系统进行FMECA分析的基础上,确定了飞机燃油系统健康管理状态监测要素,并对故障诊断及健康预测的方法进行了探讨。     

Influence of longitudinal-torsional ultrasonic-assisted vibration on micro-hole drilling Ti-6Al-4V

As Ti-6Al-4V is a typical hard to machine material, especially in micro drilling aviation parts, chip breaking difficulty is of increasing interest to explore its further development. In this study, Longitudinal-Torsional Ultrasonic Assisted Drilling (LTUAD) was employed to machine Ti-6Al-4V, and its feasibility was evaluated by comparing with Conventional Drilling (CD). By combining periodical characteristics and vibration models (the separated or the unseparated ultrasonic elliptical vibration), the influence of ultrasonic frequency on the intersection characteristics of trajectories were analyzed. And the intersection characteristics were divided into four categories: even periodicity, odd periodicity, non-odd and even periodicity and composite periodicity, indicating different capability for chip breaking. By applying the longitudinal-torsional compound vibration horn, the micro-hole drilling experiment was carried out on machining center. The chip morphology, the thrust force, and the burr height were discussed. Experimental results showed that the morphology of chips presented as smaller and more fragmentary ones in LTUAD compared with continuous helical conical ones and fold-shaped ones in CD. Compared with CD, the average values of the thrust force in LTUAD reduced by 1.98% to 24.9%. According to the burr around the hole exit in both LTUAD and CD, the height of the latter was greatly affected by the drilling parameters. And the burr around the exit of the hole were distributed rather evenly with smaller extension in LTUAD. Consequently, the LTUAD employed in micro-hole drilling was effective.     

高低频复合振动钻削CFRP/钛合金叠层结构试验

针对碳纤维增强复合材料（CFRP）和钛合金叠层结构在传统钻削过程中切削温度高、加工质量差等问题,基于低频振动钻削和高频（超声）振动钻削的优势,提出了高低频复合振动钻削的加工方法。采用自主研制的高低频复合振动钻削装置,对CFRP/钛合金叠层结构进行了制孔试验,对比研究了普通钻削、超声钻削、低频振动钻削和高低频复合振动钻削4种方式下的切削力、钛合金切屑形貌、切削温度和CFRP孔加工质量。结果表明：4种加工方式中,高低频复合振动钻削的轴向力波动相对较大,切削温度显著降低,产生的钛合金切屑呈不连续扇形且整体尺寸最小,CFRP孔出入口及孔壁的损伤程度最低,显著提高了加工质量,为复合材料叠层结构一体化制孔加工提供了指导意义。     

基于ATA2300标准的主最低设备清单建议稿开发平台研究

随着民用飞机的研制和运营,飞机主制造商需同时开展主最低设备清单建议稿（简称PMMEL）项目的开发和验证,以提高民用飞机的派遣可靠性并获得局方的认可。为实现对PMMEL 项目开发和验证过程产生的相关数据通过规范化的方法进行管理,亟需开展相关开发平台的研制和应用。研究PMMEL 项目开发的实施过程和行业需求,基于ATA2300 标准明确了PMMEL 开发和验证过程的数据管理需求;在此基础上,构建PMMEL 开发平台,经过完备的系统功能测试保证系统可靠性后,进一步采用实际的PMMEL 项目数据对平台进行概念验证,证明平台的业务符合性与匹配程度。结果表明：通过平台的建设和使用进一步规范了PMMEL项目的开发和验证数据,能够为后期运行支援类手册的编制奠定重要的数据基础,同时,平台具备持续可扩展性,能够伴随我国国产民机的持续运营开展进一步的智能化扩展。