机械密封微小形变图像测量系统像素当量的标定

在机械密封数字散斑微小形变图像测量系统中,像素当量的标定工作介于图像采集和处理之间;基于VC++2008 MFC开发了图像像素当量标定系统;系统包含了抓图、图像的阈值分割、形态学处理、扫描检测标定块的边缘及线性回归分析功能;介绍了抓图软件的开发过程;编制了形态学的腐蚀、膨胀及开/闭运算的函数,使用这些函数实现了图像的形态学处理;在形态学处理后显示图像的基础上框选包含标定块的理想区域使用扫描法获取边缘信息;对获取的边缘信息进行线性回归分析拟合出标定块的上下边缘的直线方程,根据拟合出的方程求出两条直线间的距离,最后用标定块的实际宽度除以直线间的距离即为像素当量;运行结果表明获得了亚像素级别的像素当量,保证了后期使用DSCM方法计算微小形变的精度.     

水下缆绳松弛-张紧过程的冲击张力影响因素实验研究

为了研究系泊缆绳在松弛-张紧过程产生冲击张力的影响因素,采用实验方法进行了研究.通过测试缆绳内的动态张力,分别研究了缆绳的端点运动和缆绳的自身特性对冲击张力的影响趋势,其中端点运动包括端点的运动频率和运动幅值,缆绳的自身特性包括缆绳长度、缆绳刚度及缆绳材料.结果表明,在相同的预张力和激励频率下,缆绳内的冲击张力随端点激励幅值增大而增大;在相同的激励幅值下,缆绳的冲击张力随激励频率的增大而增大.在相同的激励条件下,缆绳内的冲击张力随缆绳刚度和弹性模量的增大而增大,随缆绳长度的增大而减小.研究结果为理论分析和实际的工程设计提供参考依据.     

可见光级铝合金反射镜一体化设计与分析

高精度的反射镜对于航空航天载荷具有重要的意义。随着单点金刚石车削加工技术(SPDT)和抛光技术的发展,铝合金反射镜以快速低成本制造等优点用于可见光级的应用中。为了降低系统装调的自由度,设计了一种一体化的反射镜结构,并针对126mm口径主三反射镜进行有限元建模仿真,通过对反射镜自重分析、模态分析和加工离心力分析。得出设计的主三反射镜具有较高的动态刚度,多种工况下反射镜的镜面形变化均低于1/40λ(λ=632.8nm),可应用于可见光系统中,为金属反射镜的集成设计和制造提供一定的参考。     

Chaotification of Switching Control Systems via Dwell Time Approach

In this paper, a class of switching control systems is investigated, and a novel switching control method is developed, which can be applied to generating chaos dynamics from switching control systems through dwell time restriction. A numerical example is given to illustrate the generated chaotic dynamic behavior of the systems, and the corresponding bifurcation diagram is sketched. Then, the validity of the main results is verified together with other phase portraits.     

Loadbearing capacity of infill masonry walls considering the deformation‐based membrane effect

According to currently valid codes, it is not possible to determine the loadbearing capacity of unreinforced infill walls considering the deformation‐based membrane effect by incorporating the exact support conditions. One reason for this is the lack of a validated calculation procedure, which in addition to the equilibrium conditions also realistically represents the compatibility conditions of these systems. In the present paper, therefore, a new non‐linear analytical calculation procedure is presented. The main focus of the analysis of walls subject to area loading is the incorporation of the support conditions and thus the consideration of the deformation‐based membrane compressive force. Through generalised formulation and a standardised notation of the determination equations, different material behaviours and various support conditions can be taken into account with few parameters. On the action side, both lighter loading like wind loads and heavier loading like explosion loads can be considered. Through the implementation of the partial factor concept, it is possible to comply with the requirements of European codes and thus ensure the applicability of the analysis model.     

雪崩击穿条件下4.5kV IGBT器件的背面优化研究

The static avalanche breakdown behavior of 4.5 kV high-voltage IGBT is studied by theory analysis and experiment. The avalanche breakdown behaviors of the 4.5 kV IGBTs with different backside structures are investigated and compared by using the curve tracer. The results show that the snap back behavior of the breakdown waveform is related to the bipolar PNP gain, which leads to the deterioration of the breakdown voltage. There are two ways to optimize the backside structure, one is increasing the implant dose of the N C buffer layer, the other is decreasing the implant dose of the P C collector layer. It is found that the optimized structure is effective in suppressing the snap back behavior and improving the breakdown characteristic of high voltage IGBT.     

均布载荷作用下两端固支层合复合材料浅拱的非线性稳定性

研究两端固支层合复合材料浅拱在均布载荷作用下的非线性稳定性，首先利用文献１得到的层合浅拱在非线性几何大变形假定下的动力学控制方程，包略其惯性项，得到层合浅拱在均布载荷作用下的平衡微分方程，然后由修正迭代法对两端固支情况进行了求解，从而得到了几种销层情况下的临界载荷；最后对计算结果进行了讨论。     

箱体装配线用垫片、卡簧测量选配装置

介绍了两种箱体装配线用垫片、卡簧测量选配装置的工作原理、结构组成及测量精度。     

传动轴零件突缘叉设计分析与研究

突缘叉耳孔直径尺寸、卡簧槽距尺寸对十字轴弯曲应力、接触应力影响很大,协调确定这2个尺寸可提高万向节寿命.传动轴突缘叉耳孔中心高尺寸,对十字轴总成烧蚀失效有很大影响,通过降低中心高尺寸,减小弯矩对突缘叉两耳的作用,可保证两耳孔轴线的同轴度,保证十字轴总成滚针轴承的径向间隙,降低十字轴总成烧蚀失效率.