民机项目研制设计过程分析识别

探讨了民机项目研制设计过程。依据国际航空航天质量系列标准要求、SAE ARP4754A民用飞机与系统研制指南要求以及项目管理相关知识,运用过程方法分析识别了民机项目研制设计过程,提出了民机项目研制设计过程的过程图,并分析了设计过程与研制阶段的关系,提出了过程方法应用的具体建议。     

Collaborative optimization design of process parameter and structural topology for laser additive manufacturing

High-resolution laser additive manufacturing (LAM) significantly releases design freedom, promoting the development of topology optimization (TO) and advancing structural design methods. In order to fully take advantage of voxelated forming methods and establish the quantitative relationship between the mechanical properties of printing components and multiple process factors (laser- and process- parameters), the concurrent optimization design method based on LAM should cover the process-performance relationship. This study proposes a novel artificial intelligence-facilitated TO method for LAM to concurrently design microscale material property and macroscale structural topology of 3D components by adopting heuristic and gradient-based algorithms. The process–structure–property relationship of selective laser sintering is established by the back propagation neural network, and it is integrated into the TO algorithm for providing a systematic design scheme of structural topology and process parameter. Compared with the classical optimization method, numerical examples show that this method is able to improve the mechanical performance of the macrostructure significantly. In addition, the collaborative design method is able to be widely applied for complex functional part design and optimization, as well as case studies on artificial intelligence-facilitated product evaluation.     

航空发动机叶片砂带抛光工艺参数优化

为提高航空发动机叶片砂带抛光后的表面质量,选取影响抛光质量的主要工艺因素砂带粒度、接触力、砂带线速度、进给速度,以抛光后的叶片表面粗糙度作为评价指标,展开叶片砂带抛光工艺参数优化研究.首先,进行抛光工艺试验,基于试验结果采用BP神经网络法建立表面粗糙度与工艺参数之间的预测模型;其次,根据所建立的预测模型,采用遗传算法和粒子群算法对工艺参数进行优化对比,确定最佳工艺参数;最后,对优化后的工艺参数进行试验验证,试验结果表明:采用优化后的工艺参数进行叶片型面抛光,抛光后叶片表面粗糙度明显减小,表面质量得到了显著提高.     

工艺在智能制造生产线设计与运行控制中的重要作用

智能制造的加工工艺技术是智能制造生产线设计的基础,关系到智能制造生产线设备选择、产能分析及运行控制.智能制造的工艺技术要适应自动化生产的特点,与传统工艺相比有其特殊性.对智能制造的加工工艺技术的特点、作用及其重要性进行分析探讨,并对发展智能制造工艺技术提出建议.     

Effects of Shot Peening Process on Thermal Cycling Lifetime of TBCs Prepared by EB-PVD

Conventional two-layered thermal barrier coatings (TBCs) are prepared by electron beam physical vapor deposition (EB-PVD) with ZrO2-8 wt% Y2O3 (8YSZ) as top coat and CoCrAlY as bond coat on disk-shaped Ni based super-alloy. In this paper, three kinds of shot peening process with different lengths of operating time were adopted for bond coating. As a result, changes took place in its sur- face roughness and the surface micro-hardness. A thermal cycling test at 1 273 K×55 min and another at room temperature for 5 min were performed to study the effects of shot peening process on the thermal cycling lifetime of TBCs. It is found that a moderate shot peening process will be able to prolong the life time. The oxidation dynamic of the as-processed TBCs basically accords with the para- bolic rule, and the oxidation test also attests to the spallation between YSZ and thermal growth oxide (TGO) responsible mainly for the failure of TBCs.     

基于模糊综合评价的企业质量竞争力研究

构建了企业质量竞争力的多指标评价体系,应用模糊综合评价的方法实现了对企业质量竞争力的评价.     

工艺参数对轻质热防护组件胶接装配性能的影响

可重复使用运载器采用轻质热防护材料和应变隔离垫作为飞行器的热防护系统,轻质热防护组件通过硅橡胶胶黏剂粘接至碳纤维复合材料蒙皮表面。为提高可重复使用飞行器轻质热防护系统粘接质量,通过实验方法研究了加压压力、加压时间、表面处理方式等对轻质热防护组件与碳纤维复合材料的粘接强度的影响。结果表明：轻质热防护组件与碳纤维复合材料的粘接强度随加压压力的增大而增大,随加压时间的增长先迅速增大,当加压时间超过7 h时缓慢增大;打磨或涂处理剂表面处理方式均能提高粘接强度,同时施加两种处理方式时提高粘接强度大于52%。     

A multi-index assessment method for evaluating coverage effectiveness of remote sensing satellite

This paper deals with the multi-index assessment method for evaluating coverage effectiveness of remote sensing satellite. Because a series of satellite activities such as imaging, moving target observation, and environment investigation need to know the coverage characteristics, the coverage capability of the remote sensing satellite is the most important index. Thus, it is very important to establish the method of effectiveness evaluation of coverage characteristics. This paper focuses on the assessment of coverage effectiveness of remote sensing satellite, and proposes and designs a multi-index evaluation method based on index weight using entropy weight method and analytic hierarchy process. With a simulation case, the effectiveness evaluation results of single satellite coverage and multi-satellite coverage performance are given for the proposed assessment. The experimental results show that the established coverage characteristic model and the proposed assessment method are effective and right.     

面向MBD模型的工艺信息组织与重构系统

针对生产准备过程中人工逐项查看、查找MBD模型中产品制造信息工作量大、耗时长的问题,基于MBD模型中工艺信息的存储规范,对非几何信息的检索、提取、分析、重构技术进行了研究,在此基础上开发了面向MBD模型的工艺信息组织与重构系统,满足了制造过程中不同阶段、不同角色、不同专业对产品数模信息不同层次的使用需求。     

A Poisson multi-Bernoulli mixture filter with spawning based on Kullback–Leibler divergence minimization

In the classical form, the Poisson Multi-Bernoulli Mixture (PMBM) filter uses a PMBM density to describe target birth, surviving, and death, which does not model the appearance of spawned targets. Although such a model can handle target birth, surviving, and death well, its performance may degrade when target spawning arises. The reason for this is that the original PMBM filter treats the spawned targets as birth targets, ignoring the surviving targets’ information. In this paper, we propose a Kullback–Leibler Divergence (KLD) minimization based derivation for the PMBM prediction step, including target spawning, in which the spawned targets are modeled using a Poisson Point Process (PPP). Furthermore, to improve the computational efficiency, three approximations are used to implement the proposed algorithm, such as the Variational Multi-Bernoulli (VMB) filter, the Measurement-Oriented marginal MeMBer/Poisson (MOMB/P) filter, and the Track-Oriented marginal MeMBer/Poisson (TOMB/P) filter. Finally, simulation results demonstrate the validity of the proposed filter by using the spawning model in these three approximations.