一种新型的超空泡航行器流体动力布局

超高速水下航行器运行于巡航阶段,为减小其阻力,减小航行器的沾湿部分,会使得横滚运动的阻尼变小,加大横滚通道的控制难度.针对航行器的静稳定特性,采用艏部空化器作为俯仰和偏航运动的操纵面.由于横滚干扰力矩主要来源于航行器机动时产生的离心力,采用不对称方向舵的方式来消除横滚干扰力矩.复合抗横滚控制舵片形成方向舵的上下不平衡,同时还作为横滚控制的操纵面.采用流体动力布局形式完全摒弃了尾部安定面和操纵面,明显减小航行器航行阻力,降低横滚控制舵机的功率要求,有利于机构的小型化.同时放宽了对超空泡外形和人工通气量的准确度要求,方便了超高速水下航行器的工程实现.     

Optimum design of long-span suspension bridges considering aeroelastic and kinematic constraints

Cable supported bridges are wind prone structures. Therefore, their aerodynamic behaviour must be studied in depth in order to guarantee their safe performance. In the last decades important achievements have been reached in the study of bridges under wind-induced actions. On the other hand, non-conventional design techniques such as sensitivity analysis or optimum design have not been applied although they have proved their feasibility in the automobile or aeronautic industries. The aim of this research work is to demonstrate how non-conventional design techniques can help designers when dealing with long span bridges considering their aeroelastic behaviour. In that respect, the comprehensive analytical optimum design problem formulation is presented. In the application example the optimum design of the challenging Messina Strait Bridge is carried out. The chosen initial design has been the year 2002 design proposal. Up to a 33% deck material saving has been obtained after finishing the optimization process.     

Physics-Informed Multistage Machine Learning Strategy for the Nanomachining-Induced Plastic Deformation Behavior

The evolution of the dislocation density induced by the nanomachining process dominates the plastic deformation behaviors of materials, thus affecting the mechanical properties significantly. However, a challenging topic related to how to establish an accurate model for predicting the dislocation density based on the limited simulations and experiments arises due to the complicated thermal–mechanical coupling mechanism during the machining process. Herein, a multistage method integrating machine learning, physics, and high-throughput atomic simulation is proposed to investigate the effect of cutting speed on the dislocation behavior in polycrystal copper. Compared with the traditional one-step machine learning method, the constraint of physical features effectively improves the accuracy and generalization ability of the model. The results indicate that the dislocation behaviors depend on the competition between the cutting force and temperature. In the low-cutting speed, the predominated role of the cutting temperature leads to a rapid decline of the dislocation density. In contrast, the dislocation density tends to be stable under a high-speed cutting process due to the dynamic balance between the effects of the cutting force and temperature. Notably, the proposed strategy provides a new and universal framework to design the machining parameters to obtain high-quality products.     

Adjustable speed surface subdivision

We introduce a non-uniform subdivision algorithm that partitions the neighborhood of an extraordinary point in the ratio σ:1−σ, where σ(0,1). We call σ the speed of the non-uniform subdivision and verify C¹ continuity of the limit surface. For σ=1/2, the Catmull–Clark limit surface is recovered. Other speeds are useful to vary the relative width of the polynomial spline rings generated from extraordinary nodes.     

HALT技术在变频器中的应用初探

HALT技术可在产品设计阶段快速消除设计缺陷,缩短研发时间和成本,迅速提高产品的质量和固有可靠性。本文从HALT试验的背景出发,介绍了HALT试验的基本原理和意义。在对HALT箱各方面性能验证的基础上,针对我司11kW变频器,详细讲述了HALT试验的具体操作过程。     

基于龙虎山水电站水轮机选型设计

根据龙虎山水电站的工程概况,对该电站的设计参数进行选择分析,综合考虑各种因素,对比国内能量指标较优的转轮,从各个方面对各型号进行了比较,确定了“4大+1小”为最优方案,选择了最适合于本电站的水轮机的机型.     

稀土永磁低速同步电动机制造技术

介绍了稀土永磁低速同步电动机原理结构特点，着重论述该电机在制造中的关键技术和研究。     

永磁式双转子电机的理论与实践

根据电机学的基本理论,分析了永磁式双转子电机的原理和结构特点,结合其特点,指出这类电机生产和使用中存在的关键问题,为进一步的工程应用做好准备。     

基于80C196MC的交流牵引变频调速控制系统

本文介绍了一种以新型智能功率模块IPM，SPWM专用控制芯片80C196MC为基础构成的交流牵引变频调速控制系统，介绍了系统的控制原理及软硬件的设计方案。     

多通道同步高速数据采集系统研制

介绍了一个最高采样率为100MHz，采样精度为8bit，基于PCI总线和计算机并口的8通道同步高速数据采集系统的设计，整套系统具有同步误差小、触发方式多样、操作灵活等特点。