非线性晃动问题的ALE边界元方法

利用ＡＬＥ（任意的Ｌａｇｒａｎｇｅ－Ｅｕｌｅｒ）边界元方法数值求解了具有自由液面的非线性晃动问题，即受外力激励下流体的非线性振动问题。把ＡＬＥ有限元方法的思想应用到边界元方法中，得到了ＡＬＥ边界元方法。对于自由液面的非线性动力边界条件，应用Ｇａｌｅｒｋｉｎ加权方法进行了有限元数值离散。为了增加求解精度，对动力边界条件提出了增加误差修正项的数值求解方法。对时间变量采用Ｎｅｗｍａｒｋ方法进行离散。推导了系统非线性方程的预测－多次校正法迭代格式。进行了算例分析与比较，得到了令人比较满意的结果。     

电子设备减振设计的随机振动分析

以带减振器的电子设备为例,数字仿真和实物试验相结合,提出用强制位移法模拟预紧力的方法,对数字样机进行随机振动分析。介绍数字样机模型简化原则、网格划分技巧及重要参数的选取等,用模态试验验证了有限元模型建立的准确性,用强度校核法对仿真分析结果进行计算,判断结构设计的正确性。此强制位移法可以在计算机上仿真带减振器电子设备受到外部载荷时的动态响应,便于在设计阶段及时发现问题,避免物理样机试验后的重大返工。     

一类非线性比例积分控制规律及其应用的研究

提出一类非线性比例积分控制规律,理论分析和应用结果表明,它能显著改善控制系统的静态和动态性能。     

高职院校招收外籍留学生的探索和实践

本文主要分析了高职院校招收外籍留学生的主要途径以及招生过程中遇到的困难,对高职院校招收留学生过程中如何确定目标生源,如何发挥自身优势,通过借力和发掘多种资源来实现有效招生等方面提出了一些看法和建议。     

多域特征引导的无监督SAR图像舰船检测方法

如何在合成孔径雷达(SAR)图像标注样本有限的条件下,提升舰船检测性能一直是SAR图像处理中的热点问题。本文提出一种多域特征引导的无监督域适应方法,将知识从有标注的源域(光学图像)转移到未标注的目标域(SAR图像),降低对标记SAR图像数据依赖。同时,设计了频域转换模块、注意力区域增强模块和自适应权重模块来缩小光学、SAR图像域之间的域差距,提高源域与目标域特征对齐效率,增强网络在挑战性样本下的特征迁移能力。在公开发布的数据集上进行了大量实验。结果表明:所提的模块较基础模型AP50提升10%,总体性能优于其他先进的方法。     

低成本VARI用中温固化环氧树脂基复合材料的制备及力学性能评价

本文制备并评价了一种低成本真空辅助树脂灌注（VARI）成型工艺用的环氧树脂体系（V601）及其复合材料。本文通过DSC曲线、流变曲线、力学测试对该树脂基体及其复合材料进行评价。结果表明：V601环氧树脂体系可以在120 ℃/2 h固化制度下完全固化;树脂的工艺适用期长（黏度≤500 mPa·s,225 min）;树脂固化物的拉伸强度77.7 MPa,拉伸模量3.25 GPa,弯曲强度137.7 MPa,弯曲模量3.37 GPa。通过VARI方法制备的SW280F/V601复合材料的纤维体积含量为67.7 %,纵向拉伸强度为626 MPa,纵向拉伸模量为25.8 GPa,纵向弯曲强度为727.4 MPa,纵向弯曲模量为11.7 GPa。结果说明了V601树脂体系具有良好的VARI成型工艺适用性,制备的复合材料也具有较高的力学性能。     

驻涡燃烧室冲击/气膜冷却方案试验

针对驻涡燃烧室的结构,设计了3个试验件,其中2个采用冲击冷却方式,另一个采用气膜冷却方式.分别在不同的冷却气量下对其进行试验,获得了它们各自的冷却效率的变化规律,并将各种冷却方式的冷却效率进行了比较.试验结果显示:冷却效率随着冲击雷诺数的增大而增加,但增大到一定程度时,冷却效率增加不再明显.当开孔面积一定时,开孔越密冷却效果越好;将3个试验件比较后发现,在冷却气量较大时,冲击冷却的冷却效率稍高,但冷却气量较小时,气膜冷却会比冲击冷却表现出更好的冷却效率.     

Fuzzy adaptive robust control for space robot considering the effect of the gravity

Space robot is assembled and tested in gravity environment, and completes on-orbit service（OOS） in microgravity environment. The kinematic and dynamic characteristic of the robot will change with the variations of gravity in different working condition. Fully considering the change of kinematic and dynamic models caused by the change of gravity environment, a fuzzy adaptive robust control（FARC） strategy which is adaptive to these model variations is put forward for trajectory tracking control of space robot. A fuzzy algorithm is employed to approximate the nonlinear uncertainties in the model, adaptive laws of the parameters are constructed, and the approximation error is compensated by using a robust control algorithm. The stability of the control system is guaranteed based on the Lyapunov theory and the trajectory tracking control simulation is performed. The simulation results are compared with the proportional plus derivative（PD） controller, and the effectiveness to achieve better trajectory tracking performance under different gravity environment without changing the control parameters and the advantage of the proposed controller are verified.     

6156铝合金的人工时效与蠕变时效研究

采用光学显微及透射电子显微、维氏硬度、拉伸力学性能、电导率测试等技术,研究了试验6156铝合金的人工时效与蠕变时效强化规律与微观组织特征.结果表明,在本文试验的温度(155～175℃)-应力(0～200MPa) -时间(8～14h)范围内,采用不同制度的人工时效和蠕变时效样品的力学性能相差不大,但蠕变时效的析出相数量增...     

Investigating the soil removal characteristics of flexible tube coring method for lunar exploration

Compared with other technical solutions, sampling the planetary soil and returning it back to Earth may be the most direct method to seek the evidence of extraterrestrial life. To keep sample’s stratification for further analyzing, a novel sampling method called flexible tube coring has been adopted for China future lunar explorations. Given the uncertain physical properties of lunar regolith, proper drilling parameters should be adjusted immediately in piercing process. Otherwise, only a small amount of core could be sampled and overload drilling faults could occur correspondingly. Due to the fact that the removed soil is inevitably connected with the cored soil, soil removal characteristics may have a great influence on both drilling loads and coring results. To comprehend the soil removal characteristics, a non-contact measurement was proposed and verified to acquire the coring and removal results accurately. Herein, further more experiments in one homogenous lunar regolith simulant were conducted, revealing that there exists a sudden core failure during the sampling process and the final coring results are determined by the penetration per revolution index. Due to the core failure, both drilling loads and soil’s removal states are also affected thereby.