Direct numerical simulation of impinging shock wave and turbulent boundary layer interaction over a wavy-wall

The interaction of an impinging oblique shock wave with an angle of 30° and a supersonic turbulent boundary layer at Ma_∞=2.9 and Re_θ = 2400 over a wavy-wall is investigated through direct numerical simulation and compared with the interaction on a flat-plate under the same flow conditions. A sinusoidal wave with amplitude to wavelength ratio of 0.26 moves in the streamwise direction and is uniformly distributed across the spanwise direction. The influences of the wavy-wall on the interaction, including the characterization of the flow field, the skin-friction, pressure and the budget of turbulence kinetic energy, are systematically studied. The region of separation grows slightly and decomposes into four bubbles. Local peaks of skin-friction are observed at the rear part of the interaction region. The low-frequency shock motion can be seen in the wall pressure spectra. Analyses of the turbulence kinetic energy budget indicate that both diffusion and transport significantly increase near the crests, balanced by an amplified dissipation in the near-wall region. Proper orthogonal decomposition analyses show that the most energetic structures are associated with the separated shock and the shear layer over the bubbles. Only the bubbles in the first two troughs are dominated by a low-frequency enlargement or shrinkage.     

《微电子制造工程》本科专业课程体系建设

为我国高速发展的电子制造业培养高级应用型人才是微电子制造工程专业的培养目标。本文在分析微电子制造工程内涵的基础上，阐述了微电子制造工程专业的课程体系建设的基本指导思想、基本原则与课程体系内容。     

航天产品计算机集成制造系统研发项目管理组织结构研究

通过分析复杂航天产品的研制特点,利用现代项目管理的理论和方法,阐述了建立平衡矩阵组织结构等组织管理手段,有效地解决了航天产品计算机集成制造系统研发项目组织管理中存在的问题,为军工制造业数字化项目的实施提供可借鉴的管理经验。     

复杂作业模式下车间生产调度的建模与优化

针对某航天制造企业的实际生产环境,分析和讨论了复杂作业模式下车间生产的调度问题,并根据实际的业务流程建立了数学模型,通过自动调度与人工调度相结合的方法对其进行优化,最后采用实例对调度结果进行了验证.事实证明,这种调度机制可以同时增强系统的灵活性和稳定性,对提高车间生产效率和管理水平有很大帮助.     

Mars entry trajectory optimization using DOC and DCNLP

This paper addresses the issue of Mars atmospheric entry trajectory optimization by use of the desensitized optimal control (DOC) and Direct Collocation and Nonlinear Programming (DCNLP). Firstly, desensitized optimal control methodology is adopted to reduce the sensitivity of terminal state variables with respect to uncertainties and perturbations along the trajectory, in addition to optimizing the original performance index. Then, Direct Collocation (DC) method is used to transform the optimal control problem into Nonlinear Programming (NLP) problem which can be easily solved using the SNOPT software package. Monte Carlo simulations of error analysis show that the sensitivity of terminal state variables with respect to uncertainties and perturbations is significantly reduced, leading to improved entry precision.     

绿色切削中的MQL技术

重点介绍了MQL(Minimal Quantities of Lubricant)技术的研究现状、实际应用、环境及经济性能评价以及尚待进一步解决的问题。指出MQL与刀具技术、低温风冷和水雾冷却技术的结合使用将是未来难加工材料高速切削领域中的主要潮流。     

长江三角洲地区产业分工、产业转移分析

对长三角地区的三次产业发展和制造业产业结构变动趋势进行实证分析，得出的基本结论是长三角地区初步出现了产业分工，上海劳动密集型产业开始向周边地区转移。出现这一现象的原因包括：竞争、技术转移和产业政策引导。值得注意的是，当前还存在着生产要素流动性不强，地方政府的限制等制约产业分工、产业转移的因素，因此短期内长三角地区的产业分工和产业转移并不会大规模出现。     

数控编程系统中通用后置处理技术研究

后置处理是数控编程系统中的重要组成部分,它是将产品设计结果转化成实际生产不可缺少的环节.本文结合超人CAD/CAM集成系统的开发工作,对通用后置处理技术作了总体分析,并对其结构、程序及其功能的实现进行了具体描述.所研制的通用后置处理系统采用了交互式图形界面技术,便于使用和修改,为通用后置处理系统的实用化、通用化、商品化打下了基础.     

A fault-tolerant triple-redundant voice coil motor for direct drive valves: Design, optimization, and experiment

A direct drive actuator (DDA) with direct drive valves (DDVs) as the control device is an ideal solution for a flight actuation system. This paper presents a novel triple-redundant voice coil motor (TRVCM) used for redundant DDVs. The TRVCM features electrical/mechanical hybrid triple-redundancy by securing three stators along with three moving coils in the same frame. A permanent magnet (PM) Halbach array is employed in each redundant VCM to simplify the system structure. A back-to-back design between neighborly redundancies is adopted to decouple the magnetic flux linkage. The particle swarm optimization (PSO) method is implemented to optimize design parameters based on the analytical magnetic circuit model. The optimization objective function is defined as the acceleration capacity of the motor to achieve high dynamic performance. The optimal geometric parameters are verified with 3D magnetic field finite element analysis (FEA). A research prototype has been developed for experimental purpose. The experimental results of magnetic field density and force output show that the proposed TRVCM has great potential of applications in DDA systems.     

An aerospace bracket designed by thermo-elastic topology optimization and manufactured by additive manufacturing

Combination of topology optimization and additive manufacturing technologies provides an effective approach for the development of light-weight and high-performance structures. A heavy-loaded aerospace bracket is designed by topology optimization and manufactured by additive manufacturing technology in this work. Considering both mechanical forces and temperature loads, a formulation of thermo-elastic topology optimization is firstly proposed and the sensitivity analysis is derived in detail. Then the procedure of numerical optimization design is presented and the final design is additively manufactured using Selective Laser Melting (SLM). The mass of the aerospace bracket is reduced by over 18%, benefiting from topology and size optimization, and the three constraints are satisfied as well in the final design. This work indicates that the integration of thermo-elastic topology optimization and additive manufacturing technologies can be a rather powerful tool kit for the design of structures under thermal-mechanical loading.