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Modeling and analysis of landing collision dynamics for a shipborne helicopter
Dingxuan ZHAO, Haojie YANG, Carbone GIUSEPPE, Wenhang LI, Tao NI, Shuangji YAO
《机械工程前沿(英文)》 2021年 第16卷 第1期 页码 151-162 doi: 10.1007/s11465-020-0617-z
关键词: shipborne helicopter landing model Lagrange equations dynamics validation
吴爱国,张小明,张钊
《中国工程科学》 2005年 第7卷 第10期 页码 11-15
介绍一种新型单级旋转倒立摆系统的构成,通过对其动力学特性的分析建立了基于Lagrange方程的数学模型。在平衡点附近给出系统的线性化模型,对系统的稳定性、能控性和能观性进行了分析。
关键词: 旋转倒立摆 Lagrange方程 最优控制策略LQR
A review on membrane distillation in process engineering: design and exergy equations, materials and
《化学科学与工程前沿(英文)》 2022年 第16卷 第5期 页码 592-613 doi: 10.1007/s11705-021-2105-3
关键词: membrane distillation recent developments heat and mass transfer wetting membrane material
Farhoud KALATEH
《结构与土木工程前沿(英文)》 2019年 第13卷 第1期 页码 15-37 doi: 10.1007/s11709-018-0465-7
关键词: air blast loading concrete dams finite element dam-reservoir interaction cavitation concrete damage model
Parametric equations for notch stress concentration factors of rib–deck welds under bending loading
《结构与土木工程前沿(英文)》 2021年 第15卷 第3期 页码 595-608 doi: 10.1007/s11709-021-0720-1
关键词: notch stress concentration factor rib–deck weld parametric analysis regression analysis parametric equation
Solving nonlinear differential equations of Vanderpol, Rayleigh and Duffing by AGM
null
《机械工程前沿(英文)》 2014年 第9卷 第2期 页码 177-190 doi: 10.1007/s11465-014-0288-8
In the present paper, three complicated nonlinear differential equations in the field of vibration, which are Vanderpol, Rayleigh and Duffing equations, have been analyzed and solved completely by Algebraic Method (AGM). Investigating this kind of equations is a very hard task to do and the obtained solution is not accurate and reliable. This issue will be emerged after comparing the achieved solutions by numerical method (Runge-Kutte 4th). Based on the comparisons which have been made between the gained solutions by AGM and numerical method, it is possible to indicate that AGM can be successfully applied for various differential equations particularly for difficult ones. The results reveal that this method is not only very effective and simple, but also reliable, and can be applied for other complicated nonlinear problems.
关键词: Algebraic Method (AGM) Angular Frequency Vanderpol Rayleigh Duffing
黄志洵
《中国工程科学》 2005年 第7卷 第3期 页码 6-12
2004年6月,位于西非Oklo的美国Los Alamos实验室的核工业反应堆对实验数据做再分析后得出结论说,近20亿年内精细结构常数减小了4.5×10-8。常数不常,意味着光速有很小的变化。这是最新的与狭义相对论不符的实验报告。另一方面,光子如有质量,Maxwell方程组将被Proca方程组所取代,而磁矢位(势)A将成为可观测量。而过去和现在都有许多方法测量光子的质量。
文章的主要目的是在Proca理论框架内研究电磁波波速,发现即使在自由空间(真空)条件下也会出现超光速传播;同时又对波导与Proca波的截止现象做了比较,给出了相应的结果。
关键词: 狭义相对论 Maxwell方程组 Proca方程组 电磁波波速 光子的静止质量
考虑输入噪声的混合调制拉格朗日明确时延估计改进算法 Article
Wei XIA,Ju-lei ZHU,Wen-ying JIANG,Ling-feng ZHU
《信息与电子工程前沿(英文)》 2016年 第17卷 第10期 页码 1067-1073 doi: 10.1631/FITEE.1500417
Ali ALSALEH, Hamid M. SEDIGHI, Hassen M. OUAKAD
《结构与土木工程前沿(英文)》 2020年 第14卷 第4期 页码 1024-1032 doi: 10.1007/s11709-020-0647-y
关键词: rotor-dynamics Jeffcott rotor lateral vibrations Lagrange method system-equivalent stiffness sleeve bearings oil film induced stiffness
M. R. AKBARI,D. D. GANJI,M. NIMAFAR,A. R. AHMADI
《机械工程前沿(英文)》 2014年 第9卷 第4期 页码 390-401 doi: 10.1007/s11465-014-0313-y
In this paper, we aim to promote the capability of solving two complicated nonlinear differential equations: 1) Static analysis of the structure with variable cross section areas and materials with slope-deflection method; 2) the problem of one dimensional heat transfer with a logarithmic various surface A(x) and a logarithmic various heat generation G(x) with a simple and innovative approach entitled “Akbari-Ganji’s method” (AGM). Comparisons are made between AGM and numerical method, the results of which reveal that this method is very effective and simple and can be applied for other nonlinear problems. It is significant that there are some valuable advantages in this method and also most of the differential equations sets can be answered in this manner while in other methods there is no guarantee to obtain the good results up to now. Brief excellences of this method compared to other approaches are as follows: 1) Differential equations can be solved directly by this method; 2) without any dimensionless procedure, equation(s) can be solved; 3) it is not necessary to convert variables into new ones. According to the aforementioned assertions which are proved in this case study, the process of solving nonlinear equation(s) is very easy and convenient in comparison to other methods.
关键词: AGM extended surface heat transfer slope-deflection method
M. R. AKBARI,M. NIMAFAR,D. D. GANJI,M. M. AKBARZADE
《机械工程前沿(英文)》 2014年 第9卷 第4期 页码 402-408 doi: 10.1007/s11465-014-0316-8
The kinematic assumptions upon which the Euler-Bernoulli beam theory is founded allow it to be extended to more advanced analysis. Simple superposition allows for three-dimensional transverse loading. Using alternative constitutive equations can allow for viscoelastic or plastic beam deformation. Euler-Bernoulli beam theory can also be extended to the analysis of curved beams, beam buckling, composite beams and geometrically nonlinear beam deflection. In this study, solving the nonlinear differential equation governing the calculation of the large rotation deviation of the beam (or column) has been discussed. Previously to calculate the rotational deviation of the beam, the assumption is made that the angular deviation of the beam is small. By considering the small slope in the linearization of the governing differential equation, the solving is easy. The result of this simplification in some cases will lead to an excessive error. In this paper nonlinear differential equations governing on this system are solved analytically by Akbari-Ganji’s method (AGM). Moreover, in AGM by solving a set of algebraic equations, complicated nonlinear equations can easily be solved and without any mathematical operations such as integration solving. The solution of the problem can be obtained very simply and easily. Furthermore, to enhance the accuracy of the results, the Taylor expansion is not needed in most cases via AGM manner. Also, comparisons are made between AGM and numerical method (Runge-Kutta 4th). The results reveal that this method is very effective and simple, and can be applied for other nonlinear problems.
关键词: AGM critical load of columns large deformations of beam nonlinear differential equation
方俊,疏学明,袁宏永,郑昕
《中国工程科学》 2004年 第6卷 第1期 页码 37-43
对稳定线性热分层环境下湍浮力羽流无量纲积分方程首次采用数值解法进行求解,得出浮力通量、动量通量等参量在轴线上的变化规律以及羽流中性浮力点的高度和羽流最大上升高度。2种不同尺度空间及不同烟气羽流出口条件的实验表明,实际火灾烟气羽流最大上升高度与理论计算结果及文献经验公式相符,从而表明积分模型数值解的有效性,并为高大空间火灾烟气输运规律研究及探测技术发展提供了理论及实验依据。
数据驱动的随机微分方程辨识 Article
王亚森, 方华臻, 金骏阳, 马贵君, 何心, 代星, 岳作功, 程骋, 张海涛, 浦栋麟, 伍冬睿, 袁烨, Jorge Gonçalves, Jürgen Kurths, 丁汉
《工程(英文)》 2022年 第17卷 第10期 页码 244-252 doi: 10.1016/j.eng.2022.02.007
随机微分方程(SDE)是一种广泛用于描述受不同来源噪声干扰的复杂过程或现象的数学模型。由于数据固有的强随机性和系统动力学的复杂性,控制系统的SDE的辨识通常是一个挑战。辨识SDE的现有参数化方法的实用性通常受到数据资源不足的限制。本研究提出了一种通过稀疏贝叶斯学习(SBL)技术从候选基函数空间中搜索简洁但物理必需的表示形式来辨识SDE的新框架。更重要的是,利用SBL的解析可处理性开发了一种可以通过少量数据来高效地构建辨识SDE的线性回归模型的方法。本文利用股票和石油价格、轴承变化和风速的真实数据,以及包括广义维纳(Wiener)过程和朗之万方程在内的著名随机动力系统的仿真数据,验证了所提出框架的有效性。该框架旨在帮助专家从自然科学、经济学和工程领域的随机现象中提取随机数学模型,用于分析、预测和决策。
Burnett simulations of gas flow and heat transfer in microchannels
Fubing BAO, Jianzhong LIN
《机械工程前沿(英文)》 2009年 第4卷 第3期 页码 252-263 doi: 10.1007/s11465-009-0037-6
关键词: micro- and nanoscale gas flow slip-transition flow regime Burnett equations numerical simulation
徐世烺,王利民
《中国工程科学》 2002年 第4卷 第5期 页码 53-58
混凝土裂缝端部断裂过程区的粘聚力分布是导致混凝土断裂呈现非线性特性的重要原因。基于混凝土的断裂特性和虚拟裂缝端部存在粘聚力的分析模型,并通过分布函数的特性分析,提出了粘聚力分布函数的两种简化表达式:一为单参数待定式,另一为双参数待定式。由变形体叠加原理,推导出计算单参数待定函数公式和计算双参数待定函数代数方程组。进而通过裂缝张开位移实测数据即可求得粘聚力分布,并且给出了适当的算例分析和讨论。
标题 作者 时间 类型 操作
Modeling and analysis of landing collision dynamics for a shipborne helicopter
Dingxuan ZHAO, Haojie YANG, Carbone GIUSEPPE, Wenhang LI, Tao NI, Shuangji YAO
期刊论文
A review on membrane distillation in process engineering: design and exergy equations, materials and
期刊论文
Dynamic failure analysis of concrete dams under air blast using coupled Euler-Lagrange finite element
Farhoud KALATEH
期刊论文
Parametric equations for notch stress concentration factors of rib–deck welds under bending loading
期刊论文
Experimental and theoretical investigations of the lateral vibrations of an unbalanced Jeffcott rotor
Ali ALSALEH, Hamid M. SEDIGHI, Hassen M. OUAKAD
期刊论文
Significant progress in solution of nonlinear equations at displacement of structure and heat transfer
M. R. AKBARI,D. D. GANJI,M. NIMAFAR,A. R. AHMADI
期刊论文
Scrutiny of non-linear differential equations Euler-Bernoulli beam with large rotational deviation by
M. R. AKBARI,M. NIMAFAR,D. D. GANJI,M. M. AKBARZADE
期刊论文
数据驱动的随机微分方程辨识
王亚森, 方华臻, 金骏阳, 马贵君, 何心, 代星, 岳作功, 程骋, 张海涛, 浦栋麟, 伍冬睿, 袁烨, Jorge Gonçalves, Jürgen Kurths, 丁汉
期刊论文