考虑电荷交换的三维离子发动机栅极粒子模拟

为了对离子发动机光学系统进行数值分析，开发了考虑电荷交换的三维离子发动机栅极粒子模拟程序。模拟程序采用单元内粒子（PIC）方法，光学系统为双栅极结构，推进剂采用氙，总加速电压为1600V，栅极间距为1mm，粒子之间的电荷交换碰撞模型采用蒙特卡洛方法。采用链式存储结构存储粒子信息，可以实现数组式存储方法所不能实现的功能。使用粒子模拟程序对离子发动机光学系统进行了粒子模拟，模拟得到了栅极间的电场分布和氙离子空间分布。模拟结果表明，在所取工作参数下氙离子全部通过了栅极孔，未撞击到栅极上，验证了参数的合理性。     

基于静态存储方式的通用链表设计

本文将链表与数组存储的概念相结合,提出一种基于静态存储方式的通用链表,应用于机载防撞系统软件设计中。结果表明,这种通用链表结构设计能有效提高代码的可重用性以及避免内存泄露等可能的安全隐患。     

航空发动机试车三分钟事件记录与回放

航空发动机试车计算机辅助试验系统中开发三分钟事件记录与回放功能可以为事后的分析提供数据依据。本文着重研究了事件模型的建立的一般方法,讨论了数据记录与回放的方法,最后给出了所采用的数据结果。根据本文所论述的方法,实现了该功能并已投入了某型航空发动机试车实验使用。      

Reliability and reliability sensitivity analysis of structure by combining adaptive linked importance sampling and Kriging reliability method

The application of reliability analysis and reliability sensitivity analysis methods to complicated structures faces two main challenges: small failure probability (typical less than 10⁻⁵) and time-demanding mechanical models. This paper proposes an improved active learning surrogate model method, which combines the advantages of the classical Active Kriging – Monte Carlo Simulation (AK-MCS) procedure and the Adaptive Linked Importance Sampling (ALIS) procedure. The proposed procedure can, on the one hand, adaptively produce a series of intermediate sampling density approaching the quasi-optimal Importance Sampling (IS) density, on the other hand, adaptively generate a set of intermediate surrogate models approaching the true failure surface of the rare failure event. Then, the small failure probability and the corresponding reliability sensitivity indices are efficiently estimated by their IS estimators based on the quasi-optimal IS density and the surrogate models. Compared with the classical AK-MCS and Active Kriging – Importance Sampling (AK-IS) procedure, the proposed method neither need to build very large sample pool even when the failure probability is extremely small, nor need to estimate the Most Probable Points (MPPs), thus it is computationally more efficient and more applicable especially for problems with multiple MPPs. The effectiveness and engineering applicability of the proposed method are demonstrated by one numerical test example and two engineering applications.     

泄爆面积对连通容器预混气体泄爆影响的实验研究

在大小两个体积不等的球形容器和圆形管道组成的连通容器中,开展连通容器泄爆实验,研究连通容器等泄爆面积条件下的火焰传播和压力变化情况。结果表明：火焰从起爆容器加速传播到传爆容器,但由于容器的开口泄爆,火焰传播速率小于密闭爆炸的火焰传播速率;随泄爆面积的减小,连通容器的泄爆压力和压力上升速率均增加;连通容器爆炸受管道火焰加速和压力累积作用,在相同泄爆面积条件下,容器的最大泄爆压力和最大压力上升速率高于单个容器爆炸时的最大泄爆压力和最大压力上升速率,特别是当小容器为传爆容器时,差别更加明显,不能用单个容器的泄爆设计方法来指导连通容器的泄爆。     

Whole-process design and experimental validation of landing gear lower drag stay with global/local linked driven optimization strategy

Landing gear lower drag stay is a key component which connects fuselage and landing gear and directly effects the safety and performance of aircraft takeoff and landing. To effectively design the lower drag stay and reduce the weight of landing gear, Global/local Linked Driven Optimization Strategy (GLDOS) was developed to conduct the overall process design of lower drag stay in respect of optimization thought. The whole-process optimization involves two stages of structural conceptual design and detailed design. In the structural conceptual design, the landing gear lower drag stay was globally topologically optimized by adopting multiple starting points algorithm. In the detailed design, the local size and shape of landing gear lower drag stay were globally optimized by the gradient optimization strategy. The GLDOS method adopts different optimization strategies for different optimization stages to acquire the optimum design effect. Through the experimental validation, the weight of the optimized lower dray stay with the developed GLDOS is reduced by 16.79% while keeping enough strength and stiffness, which satisfies the requirements of engineering design under the typical loading conditions. The proposed GLDOS is validated to be accurate and efficient in optimization scheme and design cycles. The efforts of this paper provide a whole-process optimization approach regarding different optimization technologies in different design phases, which is significant in reducing structural weight and enhance design precision for complex structures in aircrafts.