船只目标三维转动对SAR成像影响的定量分析

在分析船只三维转动（横滚、俯仰、偏航）对合成孔径雷达（Synthetic Aperture Radar，SAR）成像质量的影响方面，现有文献只考虑了仅存在一维转动时的影响，未考虑三维转动同时存在时对SAR成像质量的影响。另外，现有文献主要基于船只转动对船只散射点瞬时多普勒频率的影响进行分析，并未真正与对SAR图像质量的影响关联起来。本文推导了适用于船只存在三种一维转动、同时存在三维转动时的SAR图像二维时域表达式，以及散射点方位向坐标的表达式。在上述表达式的基础上，通过分析船只上的散射点在SAR图像中的偏移情况，扩展到分析船只整体在SAR图像中的形变情况；通过分析一维转动对SAR成像的影响，扩展到分析三维转动同时存在时对SAR成像的影响。研究表明：船只三维转动引入了包络误差和相位误差，导致SAR图像中散射点模糊并在方位向偏移，且不同散射点的偏移量不同，从而使船只形状发生畸变。仿真结果验证了所推导表达式的准确性及理论分析的正确性。     

连续式跨声速风洞短轴探管设计与试验

为深入研究不同类型短轴探管的测值特性，设计了多种无需张线固定的短轴探管，通过风洞试验开展了相关探索研究。试验结果表明:不同外形参数的短轴探管与长轴探管在马赫数在0.95以下时马赫数方均根偏差量差异不超过0.000 3，马赫数修正量差异不超过0.000 8，测值曲线无明显变化；马赫数在1.0~1.4区间时，不同形式的短轴探管与长轴探管的测试结果存在明显差异，优化短轴探管头部外形参数、增加柱段长度可不同程度地降低头部对试验段流场的干扰。      

飞翼布局无人机着舰飞行动力学分析

飞翼布局无人机具有独特的气动特性,研究飞翼布局无人机着舰飞行动力学特性对设计无人机着舰控制律具有重要意义。针对飞翼布局无人机着舰下滑飞行过程,建立六自由度飞行动力学模型,并通过对着舰飞行轨迹稳定性的分析,根据飞行品质对飞行轨迹稳定性的约束,计算达到一级飞行品质要求的着舰飞行速度。通过配平计算和小扰动线性化处理,得到无人机着舰下滑运动线性模型,并分析无人机纵向和横航向的固有模态特性。结果表明,飞翼无人机着舰下滑过程中,纵向的长、短周期模态及横航向的滚转和螺旋模态收敛但收敛慢,荷兰滚模态发散。     

基于可拓学理论的航材库存管理质量评估

针对当前航材库存管理工作中存在的诸多问题,在分析航材库存管理质量影响因素的基础上,利用可拓学理论对航材库存管理质量进行评估,该方法克服了传统评估方法不能反映模糊性指标的缺陷,充分提高了评价结果的准确性,使评价结果更加科学合理,对于解决航材库存管理过程中存在的问题有益。     

Review on residual stress and its effects on manufacturing of aluminium alloy structural panels with typical multi-processes

In the aerospace industry, integrated aluminium alloy plates and stiffened panels with high accuracy and performance attract significant interest. To manufacture these panels as integrity with high accuracy, multiple processes need to be utilised, such as machining, welding and forming. During the whole manufacturing chain, residual stresses can be generated and redistributed in the components among different processes. The residual stress would significantly affect the shapes and properties of the final products. Currently, these great effects are not well considered in the design and manufacturing processes. This paper aims to draw a general understanding of the residual stress generated in the pre-manufacturing processes and its effects on subsequent manufacturing processes. The mechanisms and distributions of residual stresses generated in typical pre-manufacturing processes of structural panels, including machining, welding and additive manufacturing (AM), are firstly summarised. The detailed effects of generated residual stresses on distortion and application properties in subsequent manufacturing processes are then concluded. In addition, current methods developed for the investigation of residual stress effect in multi-processes manufacturing are critically reviewed, including experimental, analytical, finite element (FE) and machine learning methods. Furthermore, the future development trend of methods for residual stress consideration and control in the design of manufacturing processes is summarised, providing comprehensive guidance to achieve the high accurate manufacturing of aluminium alloy structural components.     

碳纤维增强PEEK薄壁结构件加工工艺研究

对PEEK/CA450材料特性、切削性能进行了分析,通过加工试验研究了该材料典型薄壁零件的工艺特点、切削参数及热处理过程,优选出最佳的工艺参数。试验结果表明:优化零件结构设计可以有效降低材料内应力和加工难度;采用PCD刀具及合适的切削参数可以保证该材料薄壁零件的加工质量;加工过程中的热处理有助于提高产品的成品率和尺寸精度。采用优化后的工艺方法,最终成功加工出符合设计性能要求的PEEK/CA450薄壁零件。