大型机翼整体壁板系统化喷丸成形技术

大型机翼整体壁板是现代大型飞机重要的大型承力整体结构件并且通常直接构成飞机的气动外形。喷丸成形是现代大型轻质高强铝合金整体壁板件成形制造的首选技术方法,但如何实现大型机翼整体壁板的精确喷丸成形一直是现代航空制造技术领域的一个难点问题。针对这一工程问题,本文采用系统化的方法,将影响大型机翼整体壁板喷丸成形精度的因素分解为壁板平面板坯误差、成形参数设计准确度、成形参数控制精度、环境因素。针对这些因素,采用基于变形位能最小的板坯优化设计来减小由板坯导致的成形误差;采用数据拟合、人工神经网络以及解析模型计算相结合的喷丸成形参数综合设计方法来提高喷丸参数设计的精度和效率;建立了板坯修正模型以修正环境温度、喷丸设备参数波动等因素对成形件形状和尺寸的影响;对于从喷丸设备上下线后仍存在的外形贴模误差,则采用手提喷丸机进行局部的渐进式校形喷丸至外形贴模。壁板喷丸成形的工程实践表明,本文所提出的系统化方法能够有效提高大型机翼整体壁板喷丸成形的精度和效率,并可满足工业生产的需求。     

多腔变断面薄壁件冷挤压过程的有限元分析

根据刚塑性有限元理论,用非线性有限元分析软件Deform3D对多腔变断面薄壁件冷挤压成形过程进行了有限元分析。模拟多腔变断面薄壁件的冷挤压变形过程,获得了挤压变形时金属流动、应力和应变分布情况,分析了产生缺陷的原因,并提出了相应的解决办法。     

电塑性及电流辅助成形研究动态及展望

航空航天等领域对高性能、轻量化和高功效构件精确成形成性的要求,迫切需要发掘和提高难变形材料的成形潜力。金属等材料在电流辅助加载时塑性提高和变形抗力降低的电塑性效应（EPE）,与传统塑性加工技术相结合发展出的电流辅助成形（EAF）工艺,可望大幅提高材料成形极限和成形质量,是实现难变形材料难成形结构精确成形制造的极具前景的技术。基于EPE测试表征方法的研究进展分析,综述了焦耳热效应、电子风效应及磁效应等EPE作用机理的研究动态,从回复、再结晶、相变及缺陷修复等方面,分析总结了电流处理对材料微观组织和性能的影响规律和作用机制,进而讨论了电塑性拔丝、轧制及微成形等EPE用于成形过程的EAF研究进展。基于上述研究动态分析,总结提出了电塑性机理方面尚待解决的科学难题、EPE驱动EAF工艺创新及工业化应用所面临的技术挑战。     

复杂薄壁件多道次充液复合成形及变形量确定

针对大拉深比、阶梯锥形的航空发动机隔热罩薄壁件,基于塑性力学方法分析了其充液拉深的变形规律,并在此基础上提出了多道次充液复合成形方法,设计了等裕量函数法以快速、合理地确定各道次变形量的分配。通过数值模拟和工艺试验,研究了关键变形量——预成形高度对成形结果的影响规律,探讨了成形过程中起皱、破裂的失效形式。结果表明,提出的工艺方法可实现复杂薄壁隔热罩构件的整体精确成形,选择适当的预成形高度可获得壁厚均匀、成形质量较好的零件。     

复杂异形截面薄壁环形件动模液压成形研究

 液压成形技术是成形薄壁零件的一种有效的解决方法。针对具有异形截面结构的某型发动机高温合金薄壁环形件,提出了液压成形结合动模轴向加载的复合成形方法,依据塑性力学方法和增量理论对成形过程进行了应力应变特征分析,并建立了有限元模型。基于有限元模拟和工艺试验,研究了筒坯成形区高度和型腔液压加载路径等关键工艺参数对零件成形结果的影响,探讨了成形过程中壁厚过度减薄、材料堆积"折叠"、形状不对称等失效形式,提出了优化的工艺参数。结果表明,提出的工艺方法可实现复杂异形截面薄壁环形件的整体精确成形,采用优化的筒坯成形区高度和液压加载路径可获得壁厚分布均匀、成形质量较好的零件。     

NiAl合金锥筒内压胀形–原位反应一体化成形工艺研究

针对NiAl合金板坯制备及复杂薄壁构件二次成形困难的技术难题,提出一种成形与原位反应一体化成形新工艺制造NiAl合金薄壳件,即先将Ni箔与Al箔交替堆叠置于模具中,再在固体颗粒介质作用下塑性成形,然后使成形后的Ni/Al叠层薄壳件继续停留在模具中,在固体颗粒介质压力作用下加热使Ni/Al叠层发生原位反应合成NiAl合金,从而制得NiAl合金薄壳件。采用扫描电子显微镜（SEM）与能谱仪（EDS）对构件微观组织进行表征,并对其高温力学性能进行测试。结果表明,采用该方法制得的NiAl合金锥筒由单一NiAl相构成,厚度方向上粗晶层与细晶层交替排布,为典型的双峰组织,无孔洞等缺陷。构件硬度为317HV且分布均匀,1000℃抗拉强度为71MPa,延伸率可达74%。     

飞机起落架内螺纹冷挤压成形过程的研究

利用高级非线性有限元软件ANSYS/LSDYNA,采用刚塑性有限元法对内螺纹冷挤压成形过程进行了模拟,得出了挤压成形过程中应力、应变的分布规律,全面地阐述了金属塑性成形有限元仿真技术.研究结果表明挤压时工件在扭矩的作用下,外表面产生压应变,内表面产生拉应变,应变自内向外逐渐增大,最外层达到最大值,大大提高挤压内螺纹件的抗拉强度和抗疲劳性能,对内螺纹冷挤压成形的工艺参数控制及塑性成形有限元仿真具有指导意义.     

圆锥杯形件超塑胀形的力学分析

 研究了圆锥杯形件的变形模式,将其成形过程分为三个阶段。根据超塑性力学的基本方程和有关假设,对每一阶段的成形过程进行了分析,得出了各阶段的最佳加载曲线方程,不同加载方式下成形时间的计算方法以及最小厚度等几何参数的计算公式。最后,进行了简短的讨论。     

航空薄壁件铣削加工动力学仿真技术

薄壁件铣削是航空工业中最常见的加工方式。航空薄壁件铣削工艺系统固有的弱刚性特点易引起切削颤振和变形,极大影响加工质量和效率。研究航空薄壁件铣削加工动力学仿真技术,指导工艺、刀具参数优选,对高质高效加工技术具有重要意义。围绕薄壁件铣削加工动力学仿真中的刀具-主轴系统动力学建模、切削瞬时薄壁件动力学建模及铣削过程动力学建模等技术进行介绍。     

气动条带式喷丸成形技术

提出气动条带式喷丸成形方法成形大型复杂型面机翼壁板,根据壁板外形曲面曲率和厚度分布,采用"整体分条,单条分区"的方法对壁板进行条带式喷丸成形。通过基础试验确定了壁板喷丸工艺参数,利用特征优化映射方法获得了壁板板坯几何模型,采用预应力方法提高了条带喷丸成形变形量。上述技术均在ARJ21大型超临界机翼壁板上获得了工程应用。     

Effect of blank quenching on shear spinning forming precision of 2219 aluminum alloy complex thin-walled components

The quenching-spinning (Q-S) process, i.e., shear spinning after blank quenching, has been increasingly utilized to form 2219 aluminum alloy complex thin-walled components. However, the changes in material property, shape and stress of the blanks after quenching will affect the spinning forming precision. In this study, the rules and mechanisms of these effects are investigated based on a combined finite element (FE) model including blank quenching and component spinning process. The results indicate that the increase of material strength and the existence of distortion of the quenched blank lead to a notable increase in the non-uniformity of the circumferential compressive stress in the spinning area and the increase of the flange swing height during spinning. These changes result in an increase in the wall thickness and component-mandrel gap of the components. The quenching residual stress has little effect on wall thickness and roundness but can noticeably reduce the component-mandrel gap. This is because that the existence of quenching residual stress of the blank can lead to the decrease of the maximum circumferential compressive stress of the workpiece in spinning and an obvious drop in the maximum compressive stress after reaching the stress peak. Quenching distortion is the main factor affecting the roundness. Moreover, the optimized installation way of the blank for spinning is obtained.     

Design of an innovative multi-stage forming process for a complex aeronautical thin-walled part with very small radii

In this paper, an aeronautical thin-walled part with a complex geometry which has several sharp bends and curvatures in different directions was investigated. This kind of part is difficult to be manufactured only in one stage. Therefore, an innovative multi-stage active hydroforming process assisted by the rigid forming method was designed. In addition, an optimized blank geometry is obtained. In fact, the main focused point of this paper is to propose a new small radius rounded corner forming technique and analyze the mechanism. Two kinds of forming modes of changing a big rounded corner into a small one, which are related to different tangential positions of the die in the process of calibration, are analyzed theoretically. Meanwhile, the stress and strain states of the deformation region are compared. The relationships between the minimum relative radii of rounded corners I and II in the first stage and the hydraulic pressure are calculated by the bending theory. Finally, the influences of the tensile-bulging effect and the interface condition of the double-layer sheet on the forming quality of the specimen are investigated. The achieved results can make a foundation for utilizing the proposed method in forming of thin-walled parts with very small radii.     

充液成形技术在航天火箭整流罩成形中的应用

基于充液形成工艺的航天火箭整流罩零件,通过数值模拟的分析与试验结果进行对比,证明了数值模拟可以给试验提供正确方向,也说明数值模拟的准确性。根据现场的试验情况,基于实际制件过程出现的一些缺陷,调整液室压力与压边力加载曲线,根据零件的拉深高度进行合理匹配,最后达到控制整个冲液成形过程的起皱和破裂的问题。实现了充液拉深工艺在大尺寸薄壁整流罩构件上的工艺升级,大大提升了零件的表面质量,从而可以解决传统落压工艺的多道次拉深工序、多道次退火及多道次敲修导致的零件变形与表面质量差等问题,从而保证零件在生产过程中表面质量和成形精度的控制。     

Plastic wrinkling prediction in thin-walled part forming process:A review

The precision forming of thin-walled components has been urgently needed in aviation and aerospace field. However, the wrinkling induced by the compressive instability is one of the major defects in thin-walled part forming. The initiation and growth of the wrinkles are interac-tively affected by many factors such as stress states, mechanical properties of the material, geometry of the workpiece and boundary conditions. Especially when the forming process involves compli-cated boundary conditions such as multi-dies constrains, the perturbation of clearances between workpiece and dies and the contact conditions changing in time and space, etc., the predication of the wrinkling is further complicated. In this paper, the current prediction methods were summa-rized including the static equilibrium method, the energy method, the initial imperfection method, the eigenvalue buckling analysis method, the static-implicit finite element method and the dynamic-explicit finite element method. Then, a systematical comparison and summary of these methods in terms of their advantages and limitations are presented. By using a combination of explicit FE method, initial imperfection and energy conservation, a hybrid method is recommended to predict plastic wrinkling in thin-walled part forming. Finally, considering the urgent requirements of com-plex thin-walled structures’ part in aviation and aerospace field, the trends and challenges in wrin-kling prediction under complicated boundary conditions are presented.     

超高温NiAl合金锥形薄壳件制备成形一体化新工艺

针对NiAl合金板坯制备及板坯成形锥形薄壳件存在的材料流动及组织性能控制困难的问题,提出了一种制备成形一体化新工艺。该工艺是将塑性成形和反应合成在同一工步中,即先将Ni/Al叠层箔置于模具中进行塑性成形,随后对成形的Ni/Al叠层箔原位加热加压反应合成NiAl合金薄壳件。采用三维扫描仪及Geomagic Studio/Qualify对锥形薄壳件的形状精度进行了分析,采用扫描电子显微镜( Scanning Electron Microscope, SEM )和电子背散射衍射( Electron Backscatter Diffraction, EBSD )技术对其微观组织进行了表征,并对构件的高温力学性能进行了测试。结果表明,采用该新工艺制备的锥形薄壳件成形效果良好,整体型面偏差尺寸在±0.1 mm以内;构件沿轴截面壁厚平均偏差为0.012 mm,沿横截面壁厚平均偏差为0.072 mm,构件轴截面壁厚分布均匀性及组织成分均匀性高于横截面。构件高温力学性能稳定,1000 °C时平均屈服强度为77.8 MPa,平均抗拉强度为82.6 MPa。NiAl合金构件的微观晶粒形貌与Ni箔的初始热处理状态及Ni/Al箔的初始厚度有关,未退火的Ni箔将延缓粗晶区晶粒的长大,减小初始箔材厚度可实现晶粒的进一步细化。     

金属橡胶毛坯铺设路径规划

针对金属橡胶毛坯铺设工艺,提出了以背景网格为基础的优化模型,利用遗传算法建立了定位销设计和路径规划的优化方法,为毛坯铺设提供了理论依据.定位销数量由底面背景网格非零网格数确定,定位销排布由遗传算法计算得到.根据定位销优化设计结果,逐层对铺设路径进行规划,优化路径比经验路径所得毛坯更加均匀、密实,铺设层数越多,路径规划的优势越明显,铺设10层时,两毛坯目标函数b的值相差50%;单层路径数对毛坯的铺设质量影响不大;随着螺旋卷铺设长度的增加,不同单层路径数铺设的毛坯接触状态趋于一致.      

TC1钛合金端盖零件热拉深成形工艺研究

针对TC1钛合金端盖零件的结构特点,分析了零件的成形难点,对热拉深工艺的模具材料、温度、压边间隙、拉深速度等对零件成形性能的影响进行了研究,提出了合理的工艺参数。结果表明,该工艺方法可实现薄壁、大拉深比的TC1钛合金零件的精确成形,采用空气脱模的方式可获得平面度满足设计要求的零件,为类似零件的取件提供了工艺参考。     

高温合金复杂薄壁零件多道次充液拉深技术

充液拉深(HDD)技术是薄壁零件成形的一种有效方法.针对难成形,复杂薄壁结构的某型发动机高温合金板材零件,通过分析锥面自由悬空区的起皱失稳现象,设计了多道次充液拉深结合刚模成形的技术方案,并建立了有限元分析模型.基于有限元模拟和工艺验证试验,研究了预成形高度和终成形液室压力等关键工艺参数对零件最终成形质量的影响,探讨了...     

基于神经网络建立液态挤压成形管、棒材工艺参数知识库

 采用人工神经网络方法,将８１组实验数据用于神经网络的建模及检测,建立了液态挤压成形管、棒材工艺参数知识库,可以对该工艺的关键参数进行较为准确的预测,从而为推动该金属成形新工艺的实际应用奠定了基础。