几何非线性样条单元

 <正>结构的有限变形与稳定性分析具有重要意义。有限元法的应用,促进了几何非线性研究工作的开展。本文在线性样条单元C’〕的基础上提出一种几何非线性样条板壳单元,壳体的应变位移关系采用Von一K巨rmon方案,以分片样条Hermite插值构造单元的位移模式。对于弱非线性问题,采用修正的Newton一Raphson法解非线性方程组。对于极值点失稳情况,以固定弧长法追踪屈曲路径,并用曲线拟合的方法确定结构的临界载荷值。     

空间光学敏感器成像组件抗力学稳定性分析与评价

摘要： 成像组件是空间光学敏感器和光学相机的核心组件,其抗力学稳定性直接影响单机的测量精度.为了提高其抗力学性能,本文首先对成像组件结构进行了力学分析,并通过试验验证了分析方法的有效性.由于仿真分析只能对抗力学稳定性进行定性评价,本文设计了实验来定量评价,并提出了一种成像组件抗力学稳定性评价方法.最后,应用该评价方法对三种结构进行了抗力学稳定性分析、试验和测试.结果表明,本文提出的评价方法与力学仿真结合试验的评价方法对三种结构的评价结论是一致的.而本文的量化评价方法可以给出结构力学试验后的滑移值和机械基准变化值,为产品的研制提供数据参考.该方法可应用于对位置变化敏感的空间光学仪器的研制过程.     

基于系统论的高职教师能力结构探讨

影响高职教育教学质量的因素很多,但由教师能力和教学行为构成的主导作用却至关重要.教育系统论要求在教育实践中,将所研究和处理的任何一件事物,当作一个系统看待,本文在深入分析高职教育培养目标、质量观的基础上,运用系统论的方法对高职教师的能力及能力结构进行了探索和分析,并提出了优化教师能力的对策.     

射流电铸技术的试验研究

电铸作为一种精密制造技术，在许多高技术领域得到成功的应用，然而，电铸存在的缺陷严重制约了其应用和发展，本文对射流电铸铜的基本工艺特性进行了试验研究，通过试验分析了射流电铸电压，电铸液射流流量以及喷嘴口径与阴极电流密度和速度之间的关系，并且对射流铸试验样件的表面质量和铸层微观形貌进行了分析，试验结果表明，射流电铸可以有效地降低浓差极化，提高极极电流密度，同时可以得到结晶细微，结构致密的铸层结构。     

炭布高温处理对2D-C/C分层缺陷的影响研究

研究了炭布高温处理对二维炭／炭复合材料(2D-C／C)分层缺陷的影响。分析了炭布处理前后炭纤维的元素及表面形貌；测试了炭布处理前后树脂基复合材料(PMC)、炭化后2D-C／C及致密后2D-C／C的层剪强度、密度、开孔率等；采用金相显微镜表征了2D-C／C的分层缺陷。结果表明，炭纤维(布)经高温处理后，其表面含氧量下降，含碳量提高，表面粗糙度增大，惰性增大；炭布高温处理降低了树脂基复合材料的ILSS．炭化后2D-C／C表现出低密度和高开孔率，炭化收缩量小、热应力小及炭化不分层等特点。     

The OSIRIS-REx Spacecraft and the Touch-and-Go Sample Acquisition Mechanism (TAGSAM)

The Origins, Spectral-Interpretation, Resource-Identification, Security and Regolith-Explorer (OSIRIS-REx) spacecraft supports all aspects of the mission science objectives, from extensive remote sensing at the asteroid Bennu, to sample collection and return to Earth. In general, the success of planetary missions requires the collection, return, and analysis of data, which in turn depends on the successful operation of instruments and the host spacecraft. In the case of OSIRIS-REx, a sample-return mission, the spacecraft must also support the acquisition, safe stowage, and return of the sample. The target asteroid is Bennu, a B-class near-Earth asteroid roughly 500 m diameter. The Lockheed Martin-designed and developed OSIRIS-REx spacecraft draws significant heritage from previous missions and features the Touch-and-Go-Sample-Acquisition-Mechanism, or TAGSAM, to collect sample from the surface of Bennu. Lockheed Martin developed TAGSAM as a novel, simple way to collect samples on planetary bodies. During short contact with the asteroid surface, TAGSAM releases curation-grade nitrogen gas, mobilizing the surface regolith into a collection chamber. The contact surface of TAGSAM includes “contact pads”, which are present to collect surface grains that have been subject to space weathering. Extensive 1-g laboratory testing, “reduced-gravity” testing (via parabolic flights on an airplane), and analysis demonstrate that TAGSAM will collect asteroid material in nominal conditions, and a variety of off-nominal conditions, such as the presence of large obstacles under the TAGSAM sampling head, or failure in the sampling gas firing. TAGSAM, and the spacecraft support of the instruments, are central to the success of the mission.     

凡士林油膜对疲劳裂纹扩展的影响

 最近国外发展了用粘接修补裂纹的新方法并已获得一些成功的应用。本文通过试验研究,提出了一条维修裂纹的新途径。很可能由此发展出一种与现有维修方法不同,简单且有效地裂纹现场维修的新方法。 2.疲劳裂纹扩展对比试验 对比试验分两组在室温、空气中,MTS810电液伺服材料试验机上进行。 第一组用由20mm工业16Mn钢板制成的中心裂纹试样（图1（a））,应力比0.05。     

Maneuvering Target Tracking in Dense Clutter Based on Particle Filtering

An improved particle filtering(IPF) is presented to perform maneuvering target tracking in dense clutter.The proposed filter uses several efficient variance reduction methods to combat particle degeneracy,low mode prior probabilities and measure-ment-origin uncertainty.Within the framework of a hybrid state estimation,each particle samples a discrete mode from its poste-rior distribution and the continuous state variables are approximated by a multivariate Gaussian mixture that is updated by an unscented Ka...     

柔性接头用低模量硅橡胶配方及界面粘接技术研究

研究了硫化剂、增粘剂和补强填料等组分对一种低模量、低硬度和高强度的硅橡胶配方力学性能的影响规律,同时研究了一种胶粘剂配方来满足硅橡胶与金属钢界面粘接的工艺要求。该硅橡胶配方的剪切模量小于0.3MPa,与钢界面粘接的剪切强度大于2.5MPa,满足柔性接头部件的性能要求。