飞机支柱式起落架落震仿真及缓冲器优化分析

主要介绍支柱式起落架缓冲器的各个参数,包括缓冲支柱的初压力、初容积、油孔面积、活塞面积、缓冲支柱行程等。介绍起落架落震时缓冲器轴向载荷的计算公式。结合具体飞机型号利用初始参数通过AD-AMS软件建立数值模型并进行仿真分析,计算结果与试验结果比较,发现两者具有较好的一致性。最后以起落架缓冲器的油孔面积作为设计参数进行优化分析,给出最优值。     

二元外压式进气道斜板和唇口参数选择的风洞试验研究

在几何不可调的二元外压式斜板进气道的设计中，选择合理的斜板和唇口几何能数是最重要的问题之一。本文对一个设计马赫数为１．８的这类进气道的斜板和唇口参数进行了风洞试验研究。用缩尺模型风洞试验，对比分析了不同斜板角和不同外侧唇口内唇角，唇缘半径对进气道内流特性的影响，结果表明，对确定的进气道布局，斜板角小的变化对进气道超音速内流总压恢复系数，稳态出口流场周向畸变指数及喘振裕度的影响很大，唇口参数小的改变     

基于激光的便携式飞机装配接缝质量检测仪及应用

介绍了一种基于激光的便携式接缝质量检测仪的工作原理及硬件组成。使用该检测仪对飞机缝隙和台阶阶差进行了测量,通过与人工测量进行对比验证,证明了该装置可实现对特征三维信息的快速自动检测,工作准确可靠。     

发动机唇口电热防冰系统性能仿真

采用三维耦合传热方法对发动机唇口电热防冰系统进行了多状态下的性能仿真,获得了唇口表面平衡温度及动态温升响应时间,以此评估防冰系统性能,并通过与冰风洞试验结果对比,对仿真过程进行了修正。研究表明:唇口表面加热区平衡温度均高于273.15 K,温升响应时间小于60 s,满足防冰需要,较为严酷的防冰状态点主要为飞行速度较大、环境温度较低的状态点;修正唇口材料导热系数后,仿真与试验结果吻合良好。研究结果能有效指导工程研制,对提高防除冰仿真分析结果的准确性提供了很好的借鉴。     

Vibration signal-based chatter identification for milling of thin-walled structure

In high speed milling aeronautical part, tool condition monitoring(TCM) is very important, because it is prone to get a chatter owing to the low stiffness of thin-walled structures. And the TCM is key technology for automated machining. In this paper, aiming to chatter monitoring in thin-walled structure milling, a variational mode decomposition – energy distribution(VMD-ED)method is proposed to improve the identification accuracy. And a moving average root mean square – mean value(MARMS-MV) ide...     

融合机床精度与工艺参数的铣削误差预测模型

为弥补现有五轴联动数控铣床加工飞机结构件的加工精度评估系统的不足,提出利用机床精度检测数据和零件特征及其工艺参数来构建评估指标体系,基于BP神经网络建立了飞机结构件加工误差预测模型。通过完成训练的网络权值分布,计算出各输入指标对最后评估结果的影响,并通过实例分析检验了模型的可靠性。结果表明,经BP神经网络模型训练得到的结果和样本零件的三坐标测量机测量数据基本吻合,选取的评价指标具有有效性。该评估模型能够有效地融合机床精度检测数据和零件特征及其加工工艺参数,对飞机结构件的铣削加工误差进行预测。     

Towards intelligent design optimization: Progress and challenge of design optimization theories and technologies for plastic forming

Plastic forming is one of enabling and fundamental technologies in advanced manufacturing chains. Design optimization is a critical way to improve the performance of the forming system, exploit the advantages of high productivity, high product quality, low production cost and short time to market and develop precise, accurate, green, and intelligent (smart) plastic forming technology. However, plastic forming is quite complicated, relating to multi-physics field coupling, multi-factor influence, multi-defect constraint, and triple nonlinear, etc., and the design optimization for plastic forming involves multi-objective, multi-parameter, multi-constraint, nonlinear, high-dimensionality, non-continuity, time-varying, and uncertainty, etc. Therefore, how to achieve accurate and efficient design optimization of products, equipment, tools/dies, and processing as well as materials characterization has always been the research frontier and focus in the field of engineering and manufacturing. In recent years, with the rapid development of computing science, data science and internet of things (IoT), the theories and technologies of design optimization have attracted more and more attention, and developed rapidly in forming process. Accordingly, this paper first introduced the framework of design optimization for plastic forming. Then, focusing on the key problems of design optimization, such as numerical model and optimization algorithm, this paper summarized the research progress on the development and application of the theories and technologies about design optimization in forming process, including deterministic and uncertain optimization. Moreover, the applicability of various modeling methods and optimization algorithms was elaborated in solving the design optimization problems of plastic forming. Finally, considering the development trends of forming technology, this paper discusses some challenges of design optimization that may need to be solved and faced in forming process.     

飞机侧壁部件装配调姿机构的设计与分析

分析了等曲率和变曲率2类飞机侧壁部件的几何特点以及对柔性装配调姿的功能需求,设计了一种新型的面向大型飞机侧壁部件数字化装配的柔性工装机构;该机构基于精密三坐标定位器对侧壁部件进行装配调姿,可等效为6自由度并联机构,通过4条支撑臂对侧壁部件进行夹持;定位器呈前后2排、前低后高布局,能够实现对侧壁部件空间6自由度位姿调整;对工装机构进行了位姿反解,根据侧壁部件的初始位姿和目标位姿反向求解出各支撑臂的关节变量,并利用计算机仿真模型进行了验证,证明了反解算法的正确性,为侧壁部件调姿运动的精确控制奠定了基础.      

面向飞机自动化装配的制孔末端执行器的设计

末端执行器是飞机装配的关键部件之一,其性能直接影响到制孔和铆接的质量,突破面向飞机自动化装配的末端执行器结构设计关键技术具有迫切的实际需求。首先,根据行业需求提出了末端执行器的总体结构,并分析了工作原理,在此基础上对末端执行器的主要功能部件进行了设计,最后研制出一套具备制孔、压紧和法向找正的试验样机,试验结果表明,该末端执行器的性能达到了飞机装配的要求。     

机器人制孔工艺参数优化有限元仿真分析

采用大型有限元DEFORM-3D和Abaqus软件分析机器人制孔的切削机理和制孔时机器人的振动机理。仿真分析了机器人制孔的切削力,并以仿真数据为基准,拟合了机器人制孔切削力的经验公式,仿真机器人的模态、刚度和阻尼,运用颤振理论分析了机器人制孔时避免振动的工艺参数范围。通过有限元仿真研究表明:有限元仿真计算有效地解决了机器人制孔工艺参数优化问题。