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数据驱动的半无限介质裂纹识别模型研究

力学学报 2024年第6期56卷 1727-1739页

作者：江守燕邓王涛孙立国杜成斌河海大学工程力学系南京211100

缺陷识别是结构健康监测的重要研究内容,对评估工程结构的安全性具有重要的指导意义,然而,准确确定结构缺陷的尺寸十分困难.论文提出了一种创新的数据驱动算法,将比例边界有限元法(scaled boundary finite element methods,SBFEM)与自... 详细信息

缺陷识别是结构健康监测的重要研究内容,对评估工程结构的安全性具有重要的指导意义,然而,准确确定结构缺陷的尺寸十分困难.论文提出了一种创新的数据驱动算法,将比例边界有限元法(scaled boundary finite element methods,SBFEM)与自编码器(autoencoder,AE)、因果膨胀卷积神经网络(causal dilated convolutional neural network,CDCNN)相结合用于半无限介质中的裂纹识别.在该模型中,SBFEM用于模拟波在含不同裂纹状缺陷半无限介质中的传播过程,对于不同的裂纹状缺陷,仅需改变裂纹尖端的比例中心和裂纹开口处节点的位置,避免了复杂的重网格过程,可高效地生成足够的训练数据.模拟波在半无限介质中传播时,建立了基于瑞利阻尼的吸收边界模型,避免了对结构全域模型进行计算.搭建了CDCNN,确保了时序数据的有序性,并获得更大的感受野而不增加神经网络的复杂性,可捕捉更多的历史信息,AE具有较强的非线性特征提取能力,可将高维的原始输入特征向量空间映射到低维潜在特征向量空间,以获得低维潜在特征用于网络模型训练,有效提升了网络模型的学习效率.数值算例表明:提出的模型能够高效且准确地识别半无限介质中裂纹的量化信息,且AE-CDCNN模型的识别效率较单CDCNN模型提高了约2.7倍.

关键词：数据驱动比例边界有限元法自编码器因果膨胀卷积神经网络裂纹识别

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深度学习视域下高职体育教学的高效设计

当代体育科技 2024年第9期14卷 151-154页

作者：孙立果晋中职业技术学院山西晋中030600

深度学习可以帮助学生更好地理解和掌握知识,并将知识应用到实际生活中,是一项十分有效的学习方式。随着我国高等教育事业的不断改革,深度学习也被引入各大高职院校中,并获得了较好的实践效果。高职体育教育作为高等教育的重要组成部分... 详细信息

深度学习可以帮助学生更好地理解和掌握知识,并将知识应用到实际生活中,是一项十分有效的学习方式。随着我国高等教育事业的不断改革,深度学习也被引入各大高职院校中,并获得了较好的实践效果。高职体育教育作为高等教育的重要组成部分,其教学质量对于学生的身心健康和全面发展具有重要影响。为此,该文采用文献资料法等研究方法,以深度学习的主要特征为切入点,分析了当前高职体育教学中存在的问题,以及深度学习视域下高职体育教学高效设计的必要性,并针对性地提出了深度学习视域下高职体育教学的高效设计实施路径,以期为今后高职体育教学的创新提供一些有益的参考。

关键词：深度学习高职体育教学高效设计

考虑材料参数空间变异性的SBFEM开裂模拟

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力学与实践 2024年第1期46卷 138-147页

作者：林安邦江守燕孙立国杜成斌河海大学力学与材料学院南京211100

论文建立了基于比例边界有限元法(scaled boundary finite element methods,SBFEM)框架的非局部宏微观损伤模型,考虑材料细观物理参数的空间变异性,探讨了材料参数的空间变异性对结构开裂过程的影响。结果表明:考虑材料参数空间变异性后... 详细信息

论文建立了基于比例边界有限元法(scaled boundary finite element methods,SBFEM)框架的非局部宏微观损伤模型,考虑材料细观物理参数的空间变异性,探讨了材料参数的空间变异性对结构开裂过程的影响。结果表明:考虑材料参数空间变异性后,裂纹扩展路径具有不确定性,建议的模型能够很好地反应材料内在的随机性;随着结构受力情况的复杂化和结构本体缺陷的增多,裂纹开裂模式的变异性也会增大。自相关长度和参数变异系数对结构开裂分析结果有重要影响。

关键词：比例边界有限元法非局部宏微观损伤模型参数空间变异性开裂模拟

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结构力学位移法实验教学装置开发及教学实践

实验室研究与探索 2024年第4期43卷 33-37页

作者：江守燕金蓉杨海霞孙立国河海大学力学与工程科学学院南京211100 大连海事大学交通运输工程学院辽宁大连116026

位移法基本原理是结构力学课程的难点和重点内容,该方法构建的基本系高度抽象,学生在学习过程中普遍感到难。将理论教学与实验教学相结合,开发了位移法基本原理的教学演示装置和实验装置。将基本系中无中生有的“刚臂”以实体部件的形... 详细信息

位移法基本原理是结构力学课程的难点和重点内容,该方法构建的基本系高度抽象,学生在学习过程中普遍感到难。将理论教学与实验教学相结合,开发了位移法基本原理的教学演示装置和实验装置。将基本系中无中生有的“刚臂”以实体部件的形式展现出来,再现“刚臂”的“放松”和“锁住”效果。从演示装置的定性分析和实验装置的定量分析2个角度阐述位移法基本原理,通过这2个装置再现位移法中原结构和基本系的变形过程。学生可以看到“结构”,看到“结构变形”,看到“基本系”及其在外荷载和结点位移单独作用下的2个状态,将抽象的位移法基本系形象化、直观化,加深了学生对位移法基本原理的理解。

关键词：结构力学位移法演示装置实验装置刚臂

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激光-电弧复合焊接铝合金的研究进展分析

华南理工大学学报（自然科学版） 2024年第3期52卷 57-74页

作者：罗震苏杰王小华肖斌斌孙立国杨越毕元波张熠轩天津大学材料科学与工程学院天津300350 天津大族天成光电技术有限公司天津300405

为早日实现“双碳”目标,轻量化制造是必经之路。铝合金以其低密度、高比强度和可回收利用等优点脱颖而出,并且具备高塑形、优良耐腐蚀能力从而可以广泛应用于各行各业,但因为其特殊的热物理性质及复杂的合金化学成分,使其焊接过程中极... 详细信息

为早日实现“双碳”目标,轻量化制造是必经之路。铝合金以其低密度、高比强度和可回收利用等优点脱颖而出,并且具备高塑形、优良耐腐蚀能力从而可以广泛应用于各行各业,但因为其特殊的热物理性质及复杂的合金化学成分,使其焊接过程中极易出现气孔、热裂纹等焊接缺陷,其焊接难题限制了铝合金在轻量化之路的进一步发展。激光-电弧复合焊接技术结合激光焊接技术与电弧焊接技术的优势,以其大焊接熔深、高焊接效率、高焊接质量著称,并逐渐成为铝合金高效优质焊接的重要熔焊工艺。为掌握铝合金激光-电弧复合焊的研究现状,本文首次通过文献计量学的方法定量分析了Web of Science(WoS)数据库中1995—2021年已发表的该领域的学术论文,并通过使用VOSviewer软件对WoS数据库数据进行了可视化处理。结果表明,焊接接头、微观组织、热影响区、力学性能及激光与电弧的相互作用为研究热点,因此本文从上述领域对铝合金的激光-电弧复合焊接进行了总结与分析,并结合激光-电弧复合焊接过程中的在线监测技术与新型激光在复合焊中的应用展开讨论分析,得出激光-电弧复合焊接铝合金中接头类型的选取,微观组织的分布,力学性能的提升措施及复合热源的相互作用机制。旨在为后续研究激光-电弧复合焊接铝合金提供参考。最后,基于当下的研究现状,本文提出了该领域面临的挑战及未来工作展望。

关键词：激光-电弧复合焊接文献计量学铝合金微观组织力学性能

Pilot time-varying control behavior modeling in refractory period with aircraft failures

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Science China(Technological Sciences) 2023年第7期66卷 2000-2012页

作者： XU ShuTing TAN WenQian WANG WeiJun sun liguo School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Nanchang 330000China

Modeling human pilot control behavior aims to understand and describe how humans control aircrafts and devices,to provide a foundation for the study of the dynamic characteristics of the human-vehicle *** the presence of aircraft failures,the human pilot has a control process of the refractory period,which may cause adverse aircraft-pilot couplings,and even lead to loss-of-control *** refractory period will make the pilot emerge with time-varying and adaptive *** paper investigates how pilot control behavior changes to adapt to the aircraft failure situation and develops a time-varying pilot model during the refractory *** aviation pilots performed a human-in-the-loop simulation experiment on a ground flight simulator to simulate the failure situations for a pitch-tracking *** characterize the pilot’s time-varying response mechanism,a time-frequency-spectrum method was used to analyze the pilot control *** innovations in the proposed model can be embodied in the description of the fuzziness,time-varying,and adaptation of the pilot for the failures in the refractory *** on fuzzy logic theory,the pilot’s judgment and identification of failures are *** adaptation of manual control behavior to time-varying aircraft dynamics is depicted by adaptive model ***-domain and time-frequency-spectrum analysis show that the simulation results of the pilot model are consistent with the human-in-the-loop experimental *** model simulation evaluations are within the range of the experimental evaluation,which shows the rationality of the timevarying behavior model of the human pilot in a failure refractory *** model has practical values for guiding the pilot to deal with abnormal conditions and predicting nonlinear aircraft-pilot couplings.

关键词： time-varying system human pilot model fuzzy control simulation aircraft-pilot couplings

Exploring mission planning method for a team of carrier aircraft launching

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Chinese Journal of Aeronautics 2019年第5期32卷 1256-1267页

作者： Yu WU Yanyang WANG Xiangju QU liguo sun College of Aerospace Engineering Chongqing University School of Aeronautic Science and Engineering Beihang University

High-level efficiency and safety are of great significance for improving the fighting capability of an aircraft carrier. One way to enhance efficiency and safety level is to organize the carrier aircraft into combat effectively. This paper studies the mission planning problem for a team of carrier aircraft launching, and a novel distributed mission planning architecture is proposed. The architecture is hierarchical and is comprised of four levels, namely, the input level, the coordination level,the path planning level and the execution level. Realistic constraints in each level of the distributed architecture, such as the vortex flow effect, the crowd effect and the motion of aircraft, are considered in the model. To solve this problem, a distributed path planning algorithm based on the asynchronous planning strategy is developed. The proposed Mission Planning Approach for Carrier Aircraft Launching(MPACAL) is validated using the setups of the Nimitz-class aircraft *** to the isolated planning architecture and the centralized planning architecture, the proposed distributed planning architecture has advantages in coordinating the launch tasks not only belonging to the same catapult but also when all different catapults are considered. The proposed MPACAL provides a modeling method for the flight deck operation on aircraft carrier.

关键词： Aircraft carrier Carrier aircraft Distributed planning architecture Mission planning Path planning

Time-varying linear control for tiltrotor aircraft

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Chinese Journal of Aeronautics 2018年第4期31卷 632-642页

作者： Jing ZHANG liguo sun Xiangju QU Liuping WANG School of Aeronautic Science and Engineering Beihang University School of Electrical and Computer Engineering RMIT University

Tiltrotor aircraft have three flight modes： helicopter mode, airplane mode, and transition mode. A tiltrotor has characteristics of highly nonlinear, time-varying flight dynamics and inertial/-control couplings in its transition mode. It can transit from the helicopter mode to the airplane mode by tilting its nacelles, and an effective controller is crucial to accomplish tilting transition missions. Longitudinal dynamic characteristics of the tiltrotor are described by a nonlinear Lagrangeform model, which takes into account inertial/control couplings and aerodynamic *** commands for airspeed velocity and attitude in the transition mode are calculated dynamically by visiting a command library which is founded in advance by analyzing the flight envelope of the tiltrotor. A Time-Varying Linear（TVL） model is obtained using a Taylorexpansion based online linearization technique from the nonlinear model. Subsequently, based on an optimal control concept, an online optimization based control method with input constraints considered is proposed. To validate the proposed control method, three typical tilting transition missions are simulated using the nonlinear model of XV-15 tiltrotor aircraft. Simulation results show that the controller can be used to control the tiltrotor throughout its operating envelop which includes a transition flight, and can also deal with vertical gust disturbances.

关键词： Constrained optimal control Inertia/control couplings Tiltrotor aircraft Time-varying control Transition mode

Effective control allocation using hierarchical multi-objective optimization for multi-phase flight

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Chinese Journal of Aeronautics 2020年第7期33卷 2002-2013页

作者： liguo sun Qing ZHOU Baoxu JIA Wenqian TAN Hangxu LI School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Shanghai Aircraft Design and Research Institute Commercial Aircraft Corporation of China Ltd.Shanghai 201210China

For different flight phases in an overall flight mission,different control and allocation preferences should be pursued considering lift,drag or maneuverability *** multi-objective flight control allocation problem for a multi-phase flight mission is *** an overall flight mission,different flight phases namely climbing,cruise,maneuver and gliding phases are ***,a multi-objective control allocation problem considering drag,lift or control energy preference is ***,considering different control preferences at different flight phases,the analytic hierarchical process method is used to construct a comprehensive performance index from different objectives such as lift or drag *** active set based dynamic programming optimization method is used to solve the real-time optimization *** the validation,the Innovative Control Effector(ICE)tailless aircraft nonlinear model and the angular acceleration measurements based adaptive Incremental Backstepping(IBKS)are used to construct the validation ***,an overall flight mission is simulated to demonstrate the efficiency of the proposed multi-phase and multi-objective flight control allocation *** results show that the comprehensive performance index for different phases,which are determined from the Analytic Hierarchy Process(AHP)method,can suitably satisfy the preference requirements for different flight phases.

关键词： Adaptive control Control allocation Flying-wing aircraft Multi-phase and multi-objective Real-time optimization