A progressive approach to predict shot peening process parameters for forming integral panel of Al7050-T7451

In this paper, a progressive approach to predict the multiple shot peening process parameters for complex integral panel is proposed. Firstly, the invariable parameters in the forming process including shot size, mass flow, peening distance and peening angle are determined according to the empirical and machine type. Then, the optimal value of air pressure for the whole shot peening is selected by the experimental data. Finally, the feeding speed for every shot peening path is predicted by regression equation. The integral panel part with thickness from 2 mm to 5 mm and curvature radius from 3200 mm to 16000 mm is taken as a research object, and four experiments are conducted. In order to design specimens for acquiring the forming data, one experiment is conducted to compare the curvature radius of the plate and stringer-structural specimens, which were peened along the middle of the two stringers. The most striking finding of this experiment is that the outer shape error range is below 3.9%, so the plate specimens can be used in predicting feeding speed of the integral panel. The second experiment is performed and results show that when the coverage reaches the limit of 80%, the minimum feeding speed is 50 mm/s. By this feeding speed, the forming curvature radius of the specimens with different thickness from the third experiment is measured and compared with the research object, and the optimal air pressure is 0.15 MPa. Then, the plate specimens with thickness from 2 mm to 5 mm are peened in the fourth experiment, and the measured curvature radius data are used to calculate the feeding speed of different shot peening path by regressive analysis method. The algorithm is validated by forming a test part and the average deviation is 0.496 mm. It is shown that the approach can realize the forming of the integral panel precisely.     

Review and propositions for the sliding/impact wear behavior in a contact interface

A thermal-solid-liquid complex operational environment induces structural interface developing a typical coupling sliding/impact wear behavior. It results in contact damage until systems fail, which may cause significant economic losses and catastrophic consequences. The key point of solving this problem is to reveal the coupling damage mechanism of the sliding/impact behavior in typical systems and life characterization under a complicate evolving environment. This has been a hot topic in the area of mechanical reliability. The main work in this paper can be concluded as follows. Firstly, the main industries in which the “sliding/impact behavior” takes place have been introduced. Then, existing studies on the wear mechanism and degree analysis are presented, which includes surface morphology analysis, wear debris analysis, and wear degree measurement. Meanwhile, existing problems in theoretical modeling and experiments in current research are summarized, so as to point out a bright direction for future research on wear prediction. They include interface contact modeling, mathematic coupling mechanism modeling, wear equation establishment, and wear life characterization, which can provide some new ideas for improving the existing studies on the sliding/impact wear behavior.     

门限自回归模型参数的局部正交设计寻优法

在采用点值图确定门限区间个数的基础上，对门自回归模型中门限值、滞后步长、各门限区间模型阶数，利用正交设计方法寻优，计算工作量锐减，却可得到精度较高的预报模型。     

一种基于移步预测消除脉冲串扰的快速算法

以毫米波主被动复合探测器为工程应用背景,通过分析信号的特点,提出一种基于移步预测思想的快速算法来消除脉冲调制信号对被动通道信号的串扰。仿真分析和实验结果表明,该方法对改善信噪比效果明显,而且具有成本低、速度快和易于工程化实现的优点。     

非线性条件下编队卫星周期性相对运动条件

利用编队卫星机械能守恒原理，提出了非线性条件下求解编队卫星周期性相对运动条件的新方法，给出了非线性周期相对运动的初始条件。编队卫星相对距离较近时，利用非线性周期运动条件，可修正Hill方程的初始条件，抑制编队卫星的长期漂移。编队卫星相对距离较大，非线性因素不可忽略时，利用非线性周期运动条件，可找到不需消耗任何燃料的周期性相对运动轨道。最后的数值仿真结果验证了该方法的正确性。     

卫星的防污染技术

在分析了国内外光学遥感卫星红外通道被水汽污染而失败的教训基础上，提出了光学遥感卫星必需全过程（从卫星设计、研制、发射至在轨运行）实施严格的防污染控制的设计思想和理论。系统地介绍了FY－1C星的防污染技术特点和经验。在轨运行表明，FY－1C所采取的一系列防污染措施是正确的。     

多传感器数据融合与弹道落点的预报

为了更精确地对弹道落点进行预报，对多传感器数据融合技术进行了,分批人出了雷达、红外系统和光测系统与传感器融合子系统连用的实例，并得出结论：单传感器的精度是难以满足现代战争需要的，寻求一种较好的融合方法来提高落点预报精度虽是一个难题，但仍是可行的。     

航天器舷窗玻璃的强度检验方法和寿命预测

以断裂力学为基础,结合热钢化玻璃应力分布的特点,首次提出了热钢化玻璃的检验试验和寿命预测方法,为热钢化舷窗玻璃的强度检验提供了理论基础。分析示例的计算表明,即使通过相同的检验应力,在不同的使用环境中允许的使用应力是不同的;不同环境下,同样的使用应力,玻璃的使用寿命相差很大。     

基于BP算法的液压泵在线状态监测及故障诊断

以液压泵振动信号的５个时域信息；峰值，峰峰值，均方根值，方差和波形系数作为最小诊断参数组合，用ＢＰ神经网络进行信息融合，提出一液压泵的神经网络在线状态监测及故障诊断系统。     

GH169合金细晶锻造工艺研究

为了提高涡轮盘的强度和低周疲劳性能,要求锻件具有ASTM10级以上的细晶组织国外在大型压力机上采用低温大变形锻造和直接时效热处理以获得性能良好的细晶锻件,而我国则试图采用锻锤生产GH169合金涡轮盘锻件,因此,需要探索适合国情的GH169合金细晶锻造工艺。根据以往的研究,δ相对GH169合金的显微组织有明显影响,因而可