可靠性设计优化的球空间设计法

可靠性设计优化（RBDO）在航空航天等领域已经被广泛应用，具有显著提高可靠性的效果；然而它包含两个迭代循环-总体优化循环和可靠性分析循环，双循环求解方法效率低下甚至难以承受。本文提出一种可以提高可靠性设计优化求解效率的方法-球空间设计法，该方法可以方便地表达搜索区域，最大可能失效点可以从极值点处精确获取；同时，该方法可以将总体优化以及可靠性分析同步进行。本文所提出的球空间法的有效性将通过2个算例进行测试，测试结果表明该方法不仅精度与同类方法持平，求解效率有明显提升，它将会对提高航空航天装备如卫星、火箭、飞行器等产品的可靠性提供更为有效的方法和技术支持。     

三维叶轮机叶片黏性反问题设计改进方法

提出了一种改进的适用于三维黏性流场的叶轮机叶片反问题设计方法。该方法假设叶片的中弧线具有虚拟移动速度,其位移量由目标载荷与实际载荷的差值计算,并利用黏性底层厚度进行限制。采用三次B样条曲线插值方法对叶片中弧线进行光顺,新叶型通过更新后的中弧线和给定的叶片厚度得到。算例验算结果表明:该方法能够根据设计意图对叶型进行修改,鲁棒性强,收敛速度快,叶片的可变自由度高,不依赖于特定的网格和求解器,具备一定的通用性。      

An equilibrium multi-objective optimum design for non-circular clearance hole of disk with discrete variables

An Equilibrium Multi-objective Optimization Model(EMOM) with self-regulated weighting factors has been proposed for the optimum design of non-circular clearance hole on the front flange of turbine disk. In the ‘‘equilibrium design", both the stress decrease around the hole and the least hole's profile variation are considered, which balances two ambivalent design goals. Specific discrete variables are applied to realize the standardization design in the optimization process, in which a Surrogate Genetic Coding Algorithm(SGCA) is introduced, and a special check module is used to get rid of repeated fitness evaluation of the samples. The method offers an equilibrium design for the non-circular clearance hole of the turbine disk with great accuracy and efficiency.     

企业知识生态系统内生与外生协同机制研究

通过对企业知识生态系统协同机制的研究,设计知识生态系统内生和外生协同机制.内生协同机制包括企业知识生态系统战略协同机制、内部环境协同机制、领导协同机制、知识主体协同机制、激励协同机制的设计.外生协同机制包括外部环境协同机制设计、行业发展协同机制设计、技术协同机制设计,从而保障企业知识生态系统正常运行.     

基于改进准则法的复合壳阻尼结构拓扑减振动力学优化

针对复合壳阻尼结构的拓扑减振优化问题，以约束阻尼层的有限单元为设计变量，采用体积比、模态频率和振型为优化约束条件，构建以多模态权重系数的结构模态损耗因子数值关系为优化目标函数的拓扑减振优化模型。为了拓展优化目标灵敏度具有不局限于某一变密度法插值模型的形式，推导了数值表达式的一般函数式。动力学优化中优化目标灵敏度正、负数集共存，使得非凸性的目标函数设计变量出现负值或优化函数寻优于局部极值点。为此，推导出复合壳阻尼结构的全域灵敏度改进优化准则法迭代格，以确保每次迭代域均为全域设计变量集。结合有限单元法编程实现了复合壳阻尼结构改进准则法，并对复合壳结构进行拓扑减振优化分析。结果表明：在敷设体积减为全覆盖的50%时，复合壳结构的模态损耗因子增减偏差为10%，具有提升减振的轻量化设计目的；各阶目标函数和拓扑构型所需的迭代次数少，中间密度区域较小，多阶优于单阶模态优化函数，易于获得全域寻优的有效减振。     

Assessment on critical technologies for conceptual design of blended-wing-body civil aircraft

Civil aviation faces great challenges because of its robust projected future growth and potential adverse environmental effects. The classical Tube-And-Wing(TAW) configuration following the Cayley's design principles has been optimized to the architecture's limit, which can hardly satisfy the further requirements on green aviation. By past decades' investigations the BlendedWing-Body(BWB) concept has emerged as a potential solution, which can simultaneously fulfill metrics of noise, emission and fuel burn. The purpose of the present work is to analyze the developments of critical technologies for BWB conceptual design from a historical perspective of technology progress. It was found that the high aerodynamic efficiency of BWB aircraft can be well scaled by the mean aerodynamic chord and wetted aspect ratio, and should be realized with the trade-offs among stability and control and low-speed performance. The structure concepts of non-cylinder pressurized cabin are of high risks on weight prediction and weight penalty. A static stability criterion is recommended and further clear and adequate criteria are required by the evaluations of flying and handling qualities. The difficulties of propulsion and airframe integration are analyzed. The energy to revenue work ratios of well-developed BWB configurations are compared,which are 31.5% and 40% better than that of TAW, using state-of-art engine technology and future engine technology, respectively. Finally, further study aspects are advocated.     

Design and analysis of a truss deployable antenna mechanism based on a 3UU-3URU unit

Space deployable structures with large calibers, high accuracy, and large folding ratios are indispensable equipment in the aerospace field. Given that the single-DOF 3RR-3RRR deployable unit cannot be fully folded, this study proposes a 3UU-3URU deployable unit with two kinds of DOF: folding movement and orientation adjustment. First, based on the G-K formula, the DOF of the 3UU-3URU unit is analyzed. Then, the 3UU-3URU unit is used to construct a deployable truss antenna with a curved surface, and the DOF of the whole deployable antenna containing multiple 3UU-3URU units is calculated. The structural design of a deployable antenna with two loops is carried out with specific parameters and geometric relations. Next, a DOF simulation of a basic combination unit composed of three 3UU-3URU units is performed. Finally, a prototype of the basic combination unit is manufactured, and the DOF of the mechanism is experimentally verified.     

火星车转移坡道柔顺性优化设计及动力学分析

对一种抽展式火星车转移坡道开展柔顺性优化设计和动力学分析。首先，分析火星车与存在异面角的坡道的挤压几何原理。然后，设计坡道的间隙机构和限位机构，并计算出机构关键设计参数的最优值，以自适应调整两侧坡道的距离，〖JP2〗减小火星车与坡道护栏之间的相互作用力。最后，对坡道下落过程和火星车在坡道上的行驶过程进行动力学仿真，验证坡道柔顺性优化设计的效果。结果表明：优化后的坡道柔顺性大幅提高，坡道可以自适应调整两侧的距离；使用优化后的坡道，可以有效降低火星车与坡道护栏的作用力，实现火星车在坡道上的安全行驶。     

组合临界流文丘里喷嘴空气流量测量方法高空舱应用分析

为满足发动机高空试验低流速进气条件下空气流量精确测量,减小进气导管气流附面层影响,弱化空气流量测量与被试发动机相关性。分析了单件/组合临界流文丘里喷嘴的工作特性,给出了组合临界流文丘里喷嘴(ACFVN)空气流量计算方法,依据给定试验发动机和高空舱尺寸设计了临界流文丘里喷嘴组合结构,得到了组合临界流文丘里喷嘴在高空舱应用的控制方法和测试布局。采用小尺寸喷嘴对组合喷嘴设计和应用方法进行了验证,结果表明:采用打开/关闭喷嘴数量和调节进气压力两种组合方式在高空舱内应用方法可行,测试布局满足测量要求,下游发动机进口截面气流紊流度优于0.3%,满足发动机高空模拟试验要求。      

基于流形结构重建的多目标气动优化算法

在多目标优化中，Pareto解集是一个分段连续的k维流形，这一规律被传统进化算法所忽略。本文提出了一种基于流形结构重建的多目标优化算法，首先利用流形结构重建方法完成解集分布从目标空间到设计空间的映射，建立解集的概率分布，并在目标空间中扩展流形结构，从而借助解集在目标空间的推进来指导优化算法的快速演化。数值算例表明本文算法对于具有不同特征的Pareto前沿具有很好的适应性，能够极大提高算法的收敛效率。多目标气动优化算例验证，本文算法相比于常规多目标进化算法能够减少约80%的计算量，极大程度缩短了气动设计的周期。