Regression model for civil aero-engine gas path parameter deviation based on deep domainadaptation with Res-BP neural network

The variations in gas path parameter deviations can fully reflect the healthy state of aeroengine gas path components and units;therefore,airlines usually take them as key parameters for monitoring the aero-engine gas path performance state and conducting fault diagnosis.In the past,the airlines could not obtain deviations autonomously.At present,a data-driven method based on an aero-engine dataset with a large sample size can be utilized to obtain the deviations.However,it is still difficult to utilize aero-engine datasets with small sample sizes to establish regression models for deviations based on deep neural networks.To obtain monitoring autonomy of each aero-engine model,it is crucial to transfer and reuse the relevant knowledge of deviation modelling learned from different aero-engine models.This paper adopts the Residual-Back Propagation Neural Network(Res-BPNN)to deeply extract high-level features and stacks multi-layer Multi-Kernel Maximum Mean Discrepancy(MK-MMD)adaptation layers to map the extracted high-level features to the Reproduce Kernel Hilbert Space(RKHS)for discrepancy measurement.To further reduce the distribution discrepancy of each aero-engine model,the method of maximizing domain-confusion loss based on an adversarial mechanism is introduced to make the features learned from different domains as close as possible,and then the learned features can be confused.Through the above methods,domain-invariant features can be extracted,and the optimal adaptation effect can be achieved.Finally,the effectiveness of the proposed method is verified by using cruise data from different civil aero-engine models and compared with other transfer learning algorithms.

Civil3d技术在河道治理中的应用分析

为了切实加强水环境保护及水资源管理与利用,近年来我国一直在加快和加大力度落实河道治理,要想保证河道治理达到预期效果,并最大程度提高河道治理工程生态效益,首先要确保河道治理设计与施工方案的科学合理性,可见借助现代化技术手段,优化和改进河道治理设计与规划是很有必要的。基于此本文首先进行Civil3d技术的梳理与说明,继而详细分析Civil3D软件在某河道治理项目的具体应用,旨在与相关工作人员相互交流、共同探讨。

Remaining useful life prediction of aero-engines based on random-coefficient regression model considering random failure threshold

Remaining useful life(RUL)prediction is one of the most crucial components in prognostics and health management(PHM)of aero-engines.This paper proposes an RUL prediction method of aero-engines considering the randomness of failure threshold.Firstly,a random-coefficient regression(RCR)model is used to model the degradation process of aeroengines.Then,the RUL distribution based on fixed failure threshold is derived.The prior parameters of the degradation model are calculated by a two-step maximum likelihood estimation(MLE)method and the random coefficient is updated in real time under the Bayesian framework.The failure threshold in this paper is defined by the actual degradation process of aeroengines.After that,a expectation maximization(EM)algorithm is proposed to estimate the underlying failure threshold of aeroengines.In addition,the conditional probability is used to satisfy the limitation of failure threshold.Then,based on above results,an analytical expression of RUL distribution of aero-engines based on the RCR model considering random failure threshold(RFT)is derived in a closed-form.Finally,a case study of turbofan engine is used to demonstrate the effectiveness and superiority of the RUL prediction method and the parameters estimation method of failure threshold proposed.

An Inter-Shaft Bearing Fault Diagnosis Dataset from an Aero-Engine System

In this paper,the aero-engine test with inter-shaft bearing fault is carried out,and a dataset is proposed for the first time based on the vibration signal of rotors and casings.First,a test rig based on a real aero-engine is established,driven by motors and equipped with a lubricating system.Then,the aero-engine is disassembled and assembled following the specification process,and the inter-shaft bearing with artificial fault is replaced.Next,the aero-engine test is conducted at 28 groups of high-and low-pressure speeds.Six measuring points are arranged,including two displacement sensors to test the displacement vibration signals of the low-pressure rotor and four acceleration sensors to test the acceleration vibration signals of the casing.The test results are integrated into an inter-shaft bearing fault dataset.Finally,based on the dataset in this paper,frequency spectrum,envelope spectrum,CNN,LSTM,and TST are used for fault diagnosis,and the results are compared with those of CWRU and XJTU datasets.The results show that the characteristic fault frequency cannot be found directly in the spectrum and envelope spectrum corresponding to this paper’s dataset but in CWRU and XJTU datasets.Using CNN,LSTM,and TST for fault diagnosis of the dataset in this paper,the accuracy is 83.13%,85.41%,and 71.07%,respectively,much lower than the diagnosis results of CWRU and XJTU datasets.It can be seen that the dataset in this paper is closer to the actual fault diagnosis situation and is a more challenging dataset.This dataset provides a new benchmark for the validation of fault diagnosis methods.Mendeley data:https://github.com/HouLeiHIT/HIT-dataset.

基于Civil 3D部件编辑器的矿山排土场参数化设计研究

近年来,民用建筑行业BIM技术得到迅速发展,将其应用于有色冶金矿山设计工作势在必行,改变以往人工计算、应用AutoCAD插件出图的现状。为实现排土场参数化设计,结合排土场设计经验和计算机语言,基于Civil 3D部件编辑器(SAC)研究了参数化设计流程;针对排土场横断面形式,创建了多级边坡部件参数化模型,实现了快速建模、三维模型到二维图纸的转换以及排土场库容精确计算。基于SAC的排土场三维参数化设计技术促进了设计效率和精度的提升,总结形成了参数化设计技术在排土场设计过程中的应用流程,为类似项目提供参考。

基于Civil 3D进行符合国标的超高加宽设计

BIM的快速发展为道路设计提供了新的发展契机。作为一款成熟的道路设计BIM软件,无论是设计规范,还是装配部件,Civil 3D都支持自主定义,这为道路行业BIM的发展提供了一个很好的设计平台。在各等级道路中,道路的超高加宽设计对于行车的安全性与舒适性至关重要,但是在进行路线超高加宽设计时,Civil 3D所依托的是美国标准规范。为了让设计更适合中国道路实际情况,根据中国路线设计规范修编Civil 3D的超高加宽设计文件是至关重要的,可以为中国标准下的公路行业BIM设计发展提供一定的帮助。

The Positive Significance of Confucian Civilization in Peace Building

The Confucian emphasis on benevolence and empathy can be applied in conflict resolution processes.When parties in conflict embrace these values,it becomes easier to find common ground,compromise,and work towards peaceful solutions.Confucian civilization,with its emphasis on ethics,harmony,and diplomacy,offers valuable contributions to peace-building efforts in the contemporary world.By promoting virtuous leadership,fostering cross-cultural understanding,and emphasizing ethical governance,Confucianism can play a positive role in achieving and maintaining global peace.Confucianism continues to exert significant influence in the contemporary world,particularly in the context of peace-building efforts.This article explores the positive significance of Confucian civilization in contributing to peace-building endeavors globally.

基于Midas Civil的桥梁承载力检算分析

文章以衡山路跨陇海立交桥第1联边跨、中跨受力最不利梁为工程研究案例,基于Midas Civil有限元软件对桥梁承载力进行检算分析,并介绍桥梁工程检算参数取值。通过Midas Civil建立桥梁模型,模拟桥梁结构和荷载,对比分析桥梁元结构的承载能力和桥梁实际承载能力,结果表明该桥梁结构满足规范荷载等级使用要求。研究可为同类型工程提供经验参考。

BDSec:Security Authentication Protocol for BeiDou-II Civil Navigation Message

Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-II civil navigation message(BDII-CNAV)are vulnerable to spoofing attack and replay attack.To solve this problem,we present a security authentication protocol,called as BDSec,which is designed by using China’s cryptography Shangyong Mima(SM)series algorithms,such as SM2/4/9 and Zu Chongzhi(ZUC)algorithm.In BDSec protocol,both of BDII-CNAV and signature information are encrypted using the SM4 algorithm(Symmetric encryption mechanism).The encrypted result is used as the subject authentication information.BDSec protocol applies SM9 algorithm(Identity-based cryptography mechanism)to protect the integrity of the BDII-CNAV,adopts the SM2 algorithm(Public key cryptosystem)to guarantee the confidentiality of the important session information,and uses the ZUC algorithm(Encryption and integrity algorithm)to verify the integrity of the message authentication serial number and initial information and the information in authentication initialization sub-protocol respectively.The results of the SVO logic reasoning and performance analysis show that BDSec protocol meets security requirements for the dual user identity authentication in BDS and can realize the security authentication of BDII-CNAV.

基于Civil3D集成造价法在截渗墙投资编制中的应用

常规截渗墙造价工作在计算各地层工程量时占用大量时间,导致造价编制的效率与精度很难同时得到保证。为了解决这个问题,将基于Civil3D集成造价方法在截渗墙造价编制中进行应用,通过引入Civil3D软件进行三维算量,将各个地层的工程量直接导出至Excel,计算工程量方便快捷,并且统一土层信息制作土层信息表,通过参数判别自动匹配单价模板,提高了造价工作的效率与成果质量。

Problem Analysis and Effective Strategies of Ecological Civilization Education for Undergraduates in the New Age

The ecological civilization in the new age is one important aspect for undergraduates.We must enhance the concept of their civilization and improve the quality of civilization.Carrying out ecological civilization education in colleges and universities has a practical significance for enriching the contents of ideological and political education to realize their all-round development.Nowadays,some undergraduates lack awareness of ecological civilization and ignore its importance.For this reason,undergraduates need to pay attention to ecological civilization and improve their own ecological civilization literacy to promote the all-round development in qualities in the new age.This paper mainly analyzes the current problems in undergraduates’ecological civilization education and explores effective strategies to solve the current problems in undergraduates’ecological civilization education.The strategies include integrating ecological civilization resources,innovating methods of ecological civilization,strengthening ecological educator team construction,embodying ecological culture in campus construction and creating the atmosphere,emphasizing innovative practices for ecological civilization,strengthening publicity of social-ecological civilization,and attaching importance to family education of ecological civilization.

Research on the Development Path of Green Marine Economy in the Era of Ecological Civilization

This article explores the development path of the green marine economy in the era of ecological civilization.It highlights the importance of developing a green marine economy and how it has become a global consensus.The article suggests that China should take proactive measures to optimize its marine industrial structure,promote marine scientific and technological innovation,strengthen marine resource protection and environmental governance,and enhance the competitiveness of the marine economy.The ultimate objective is to achieve sustainable development of the ocean,expand the blue economic space,and accomplish the goal of green marine economic development.

Civil 3D在工程施工复杂场地土方计算中的应用

在工程施工过程中往往涉及到场地土方的计算,尤其是在一些复杂的场地内修建道路、管线或者构筑物时,如何更高效准确的计算场地土方,对设计方案编制、现场土方平衡亦或工程量核算都是一项重要的工作。随着BIM技术的发展,Civil 3D软件是Autodesk为土木与基础设施行业提供的三维设计解决方案,适用于岩土、勘测、总图、场地规划、水利工程、道路设计等多个不同的应用领域,Civil 3D不仅提供了强大的地形分析和处理功能,更重要的是能从多种源数据快速灵活的创建三维的数字地形模型。根据我长期在市政工程施工中的实践,通过对Civil 3D软件的应用,利用其三维建模和曲面编辑的优势,运用“点-线-面-体”的建模思路,将一维的点(x,y,z)转换成三维的体,总结出一种适用于复杂土方计算的方法。

一种基于Civil3D的调蓄水池土方工程量统计方法

土方工程量统计是工程项目中的重要工作,关系到项目实施的各个环节。Civil3D软件依据调蓄水池原始地形创建原始地形曲面,结合调蓄水池的设计参数,对“体积面板”模块中三角网体积曲面计算原理进行二次开发,调用软件的API函数可实现快速统计调蓄水池土石方工程量,相较于传统统计土石方工程量的方法,该方法计算精度高、运算时间短、实时性高,大大提高了设计人员的工作效率,为调蓄水池的工程设计提供新的设计思路。

基于AUTO Civil 3D的水利工程勘察设计

本文通过无人机技术和数字高程模型,采集水库工程的地形和地貌数据;将原始工程资料、采集的地貌数据以及地形数据,输入至AUTO Civil 3D软件中,生成水库工程地形曲面模型和地质三维实体模型,完成模型颜色渲染,进行水库工程勘察设计。这种基于AUTO Civil 3D的水利工程勘察方法测试结果表明,该方法能够有效完成水利工程地质模型的生成,呈现地质信息的实体结果;模型的构建精度较高,可有效完成航道疏浚时河底清淤勘察设计。

基于MIDASCivil的C50大体积预应力砼承台——冷却水管布设及温控措施

C50大体积预应力混凝土承台因标号高,温升大,且需要一次性浇筑完成和预应力张拉,所以更易产生裂缝,对温度的控制要求更高。为有效地控制C50大体积预应力混凝土施工中温度裂缝的产生和发展,通过在项目施工前使用MIDAS civil软件,对预埋冷却水管的数量和布设方式进行反复的试算和设计,可较为合理地布设冷却水管,同时结合其他温控措施,从而有效解决混凝土施工期水化热产生的温度应力裂缝。

基于MIDAS CIVIL的桥梁健康监测与评估

以福建省三明市某桥梁为分析案例,利用MIDAS CIVIL软件建立桥梁三维有限元分析模型,对桥梁在设计荷载下应变、挠度变化进行模拟仿真,分析出最不利点位。建立桥梁健康监测系统,采集桥梁实时数据,建立桥梁结构预警阈值,实现桥梁结构的损伤预警,保障桥梁结构健康安全,为桥梁养护提供参考。

RESEARCH AND DEVELOPMENT OF HIGH TEMPERATURESTRUCTURAL MATERIALS FOR AERO-ENGINE APPLICATIONS

The status of research, development of superalloys and materials processing ＆ fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superqlloys for aero-engine disks and rings, and powder metalurgy （PM） superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification, spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.

Convergence Analysis of the Numerical Solution for Cathode Design of Aero-engine Blades in Electrochemical Machining

As a main difficult problem encountered in electrochemical machining （ECM）, the cathode design is tackled, at present, with various numerical analysis methods such as finite difference, finite element and boundary element methods. Among them, the finite element method presents more flexibility to deal with the irregularly shaped workpieces. However, it is very difficult to ensure the convergence of finite element numerical approach. This paper proposes an accurate model and a finite element numerical approach of cathode design based on the potential distribution in inter-electrode gap. In order to ensure the convergence of finite element numerical approach and increase the accuracy in cathode design, the cathode shape should be iterated to eliminate the design errors in computational process. Several experiments are conducted to verify the machining accuracy of the designed cathode. The experimental results have proven perfect convergence and good computing accuracy of the proposed finite element numerical approach by the high surface quality and dimensional accuracy of the machined blades.

Machining the Integral Impeller and Blisk of Aero-Engines:A Review of Surface Finishing and Strengthening Technologies

The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has signif- icant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and inte- grated finishing and strengthening technologies and dis- cusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.