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学者姓名：李凤明
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摘要 ：
The band-gap properties of non-uniform periodic beams are analyzed using numerical and experimental methods. The flexural wave equations are established based on the Euler-Bernoulli and Timoshenko beam theories. The beams with periodically variable cross sections are investigated. The transfer matrix method is used to explore the dynamic behaviors of the periodic beams, that is, the natural frequencies of the finite periodic beams with different cross-section ratios between the adjacent sub-cells and the band-gaps of the infinite periodic beams based on the Bloch theory. The validity and accuracy of the band-gaps acquired by the present method are verified by comparing the results with those obtained from the finite element method and the vibration experiments. The effects of the different lengths of adjacent sub-cells on the band-gap properties are then investigated. The research results and conclusions should be useful in the study of vibration control applications.
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| GB/T 7714 | Gao, Fuchao , Wu, Zhijing , Li, Fengming et al. Numerical and experimental analysis of the vibration and band-gap properties of elastic beams with periodically variable cross sections [J]. | WAVES IN RANDOM AND COMPLEX MEDIA , 2019 , 29 (2) : 299-316 . |
| MLA | Gao, Fuchao et al. "Numerical and experimental analysis of the vibration and band-gap properties of elastic beams with periodically variable cross sections" . | WAVES IN RANDOM AND COMPLEX MEDIA 29 . 2 (2019) : 299-316 . |
| APA | Gao, Fuchao , Wu, Zhijing , Li, Fengming , Zhang, Chuanzeng . Numerical and experimental analysis of the vibration and band-gap properties of elastic beams with periodically variable cross sections . | WAVES IN RANDOM AND COMPLEX MEDIA , 2019 , 29 (2) , 299-316 . |
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摘要 ：
An effective methodology is developed to investigate the vibration of the sandwich plate with pyramidal lattice core. Equation of motion of lattice sandwich plate is established by Hamilton's principle. Displacement fields are expressed with a simple method, and the natural frequencies of the lattice sandwich plate are conveniently calculated. The correctness of the analytical method is verified by comparing the present results with published literatures. The effects of structural and material parameters on the vibration characteristics of lattice sandwich plate are analyzed. The present method will be useful for vibration analysis and design of lattice sandwich plates.
关键词 ：
free vibration free vibration Hamilton's principle Hamilton's principle lattice truss core lattice truss core natural frequency natural frequency Sandwich plate Sandwich plate
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| GB/T 7714 | Guo, Zhenkun , Liu, Chunchuan , Li, Fengming . Vibration analysis of sandwich plates with lattice truss core [J]. | MECHANICS OF ADVANCED MATERIALS AND STRUCTURES , 2019 , 26 (5) : 424-429 . |
| MLA | Guo, Zhenkun et al. "Vibration analysis of sandwich plates with lattice truss core" . | MECHANICS OF ADVANCED MATERIALS AND STRUCTURES 26 . 5 (2019) : 424-429 . |
| APA | Guo, Zhenkun , Liu, Chunchuan , Li, Fengming . Vibration analysis of sandwich plates with lattice truss core . | MECHANICS OF ADVANCED MATERIALS AND STRUCTURES , 2019 , 26 (5) , 424-429 . |
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摘要 ：
So far, little attention has been paid to the vibration analysis of multi-span lattice sandwich beams, particularly using the assumed mode method (AMM). In this paper, the mode shapes of multi-span sandwich beams are assumed as those of uniform beams modified by the interpolation functions. The equation of motion of the beam is established using Hamilton's principle. The natural frequencies of multi-span pyramidal and Kagome sandwich beams so calculated agree well with those determined using the ANSYS software, which indicates that the present methodology is suitable for solving multi-span sandwich beams with lattice truss cores. The effects of Young's modulus, damping and geometric parameters of cores and sheets on the natural frequencies and time domain responses of two kinds of multi-span sandwich beams are analyzed. When the truss radius and sheet thickness are increased, the natural frequencies are increased initially and then decrease, while the vibration amplitudes at the mid-points of both the multi-span pyramidal and Kagome sandwich beams decrease. With the increase of the inclination angle of the truss alpha(c), the natural frequencies of structures experience a slight decline. In contrast, the amplitudes at the mid-points of the two different three-span sandwich beams both rise.
关键词 ：
Assumed mode method Assumed mode method Free vibration analysis Free vibration analysis Interpolation functions Interpolation functions Multi-span lattice sandwich beam Multi-span lattice sandwich beam Natural frequency Natural frequency
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| GB/T 7714 | Zhao, Zhao , Wen, Shurui , Li, Fengming . Vibration analysis of multi-span lattice sandwich beams using the assumed mode method [J]. | COMPOSITE STRUCTURES , 2018 , 185 : 716-727 . |
| MLA | Zhao, Zhao et al. "Vibration analysis of multi-span lattice sandwich beams using the assumed mode method" . | COMPOSITE STRUCTURES 185 (2018) : 716-727 . |
| APA | Zhao, Zhao , Wen, Shurui , Li, Fengming . Vibration analysis of multi-span lattice sandwich beams using the assumed mode method . | COMPOSITE STRUCTURES , 2018 , 185 , 716-727 . |
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摘要 ：
This paper describes a new methodology capable of analyzing coupled bending and torsional vibrations in non-uniform thin-walled beams. The transfer matrix method (TMM) and the differential transform method (DTM) are combined to create the proposed transfer differential transform method (TDTM) for solving equations coupling bending and torsional vibrations in non-uniform beams. Compared with the finite element method (FEM), the TDTM utilizes a type of changeable mode shape functions so that the number of meshed elements can be reduced greatly when the beam's geometric size is uniform. The equations of motion of the non-uniform thin-walled beams are established using Hamilton's principle. The method considers both the warping and rotary effects of the beam section. The natural frequencies and mode shapes of the bending and torsional components are obtained using the TDTM. The accuracy of solutions can be controlled by the mesh density and the series expansion order of the mode shape whose ranges are also discussed. For illustrative purposes, the natural frequencies and the frequency response curves of a uniform beam and a non-uniform beam are studied respectively and are validated by experiments. The effects of warping and the distance between the centroid of a given section and the corresponding shear center on the vibration properties of the beam are also investigated.
关键词 ：
Bending and torsional vibrations Bending and torsional vibrations Differential transform method Differential transform method Modal test Modal test Non-uniform thin-walled beams Non-uniform thin-walled beams Transfer matrix method Transfer matrix method
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| GB/T 7714 | Zhou, Jingwei , Wen, Shurui , Li, Fengming et al. Coupled bending and torsional vibrations of non-uniform thin-walled beams by the transfer differential transform method and experiments [J]. | THIN-WALLED STRUCTURES , 2018 , 127 : 373-388 . |
| MLA | Zhou, Jingwei et al. "Coupled bending and torsional vibrations of non-uniform thin-walled beams by the transfer differential transform method and experiments" . | THIN-WALLED STRUCTURES 127 (2018) : 373-388 . |
| APA | Zhou, Jingwei , Wen, Shurui , Li, Fengming , Zhu, Yu . Coupled bending and torsional vibrations of non-uniform thin-walled beams by the transfer differential transform method and experiments . | THIN-WALLED STRUCTURES , 2018 , 127 , 373-388 . |
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摘要 ：
Although some investigations on the vibration properties of multi-span beams have been conducted, studies on multi-span Timoshenko beams by using the assumed mode method have been relatively few. In this paper, the multi-span Timoshenko beams are investigated, and the mode shapes of the beams are modified by the interpolation functions to model the vibration modes of the multi-span beams. Hamilton's principle is applied to establish the equation of motion of the structure, and the natural circular frequencies and the free vibration responses of the multi-span beams are obtained. The numerical results demonstrate good agreement between the present results and those from the open literature and the ANSYS software. The influences of the length-thickness ratio, the disorder degree and the span number on the free vibration of the structure are also analyzed. It is observed that the displacement amplitude and the vibration period at the midpoint of the three-span Timoshenko beams are reduced when the disorder degree and the length-thickness ratio are reduced. The increase in the span number of the multi-span beams with equal spans leads to the decrease in the displacement amplitude and the period of the structures. Furthermore, some interesting phenomena are found, e.g., the same even-order frequencies of different three-span beams are equal under specific disorder degree.
关键词 ：
Assumed mode method Assumed mode method Disorder degree Disorder degree Free vibration response Free vibration response Interpolation functions Interpolation functions Multi-span beam Multi-span beam Natural circular frequency Natural circular frequency
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| GB/T 7714 | Zhao, Zhao , Wen, Shurui , Li, Fengming et al. Free vibration analysis of multi-span Timoshenko beams using the assumed mode method [J]. | ARCHIVE OF APPLIED MECHANICS , 2018 , 88 (7) : 1213-1228 . |
| MLA | Zhao, Zhao et al. "Free vibration analysis of multi-span Timoshenko beams using the assumed mode method" . | ARCHIVE OF APPLIED MECHANICS 88 . 7 (2018) : 1213-1228 . |
| APA | Zhao, Zhao , Wen, Shurui , Li, Fengming , Zhang, Chuanzeng . Free vibration analysis of multi-span Timoshenko beams using the assumed mode method . | ARCHIVE OF APPLIED MECHANICS , 2018 , 88 (7) , 1213-1228 . |
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摘要 ：
The thermal effects on the buckling, postbuckling and nonlinear vibration behaviors of composite laminated trapezoidal plates are studied Aiming at the complex plate structure and to simulate the temperature distribution of the plate, a finite element method (FEM) is applied in this paper. In the temperature model, based on the thermal diffusion equation, the Galerkin's method is employed to establish the temperature equation of the composite laminated trapezoidal plate. The geometrical nonlinearity of the plate is considered by using the von Karman large deformation theory, and combining the thermal model and aeroelastic model, Hamilton's principle is employed to establish the thermoelastic equation of motion of the composite laminated trapezoidal plate. The thermal buckling and postbuckling of the composite laminated rectangular plate are analyzed to verify the validity and correctness of the present methodology by comparing with the results reported in the literature. Moreover, the effects of the temperature with the ply-angle on the thermal buckling and postbuckling of the composite laminated trapezoidal plates are studied, the thermal effects on the nonlinear vibration behaviors of the composite laminated trapezoidal plates are discussed, and the frequency-response curves are also presented for the different temperatures and ply angles.
关键词 ：
laminated trapezoidal plates laminated trapezoidal plates nonlinear vibration nonlinear vibration thermal buckling and postbuckling thermal buckling and postbuckling
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| GB/T 7714 | Jiang, Guoqing , Li, Fengming , Zhang, Chuanzeng . Postbuckling and nonlinear vibration of composite laminated trapezoidal plates [J]. | STEEL AND COMPOSITE STRUCTURES , 2018 , 26 (1) : 17-29 . |
| MLA | Jiang, Guoqing et al. "Postbuckling and nonlinear vibration of composite laminated trapezoidal plates" . | STEEL AND COMPOSITE STRUCTURES 26 . 1 (2018) : 17-29 . |
| APA | Jiang, Guoqing , Li, Fengming , Zhang, Chuanzeng . Postbuckling and nonlinear vibration of composite laminated trapezoidal plates . | STEEL AND COMPOSITE STRUCTURES , 2018 , 26 (1) , 17-29 . |
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摘要 ：
针对复合材料层合悬臂板,在其上表面铺设压电纤维复合材料MFC作为作动器,同时在下表面对称铺设压电薄膜(PVDF)作为传感器,应用速度反馈控制方法研究其主动振动控制.运用Hamilton原理和假设模态法推导含多个MFC作动器的复合材料层合板的力电耦合结构运动方程,其中考虑了MFC作动器作为悬臂板附加质量及刚度的影响.基于模态控制力/力矩最大化的原则,将多对MFC作动器/PVDF传感器铺设在层合悬臂板前几个低阶模态应变最大的区域,通过算例得出结构受控前后的时域和频域响应以及各MFC作动器所需的控制电压曲线.讨论复合材料层合板纤维铺设角度不同情况下,作动器MFC铺设位置及压电纤维铺设方向的相应变化.
关键词 ：
纤维铺设角度 纤维铺设角度 模态控制 模态控制 压电纤维复合材料(MFC) 压电纤维复合材料(MFC) 复合材料悬臂板 复合材料悬臂板
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| GB/T 7714 | 李蒙 , 李凤明 . 采用MFC压电作动器对复合材料悬臂板振动主动控制 [J]. | 动力学与控制学报 , 2017 , 15 (4) : 342-349 . |
| MLA | 李蒙 et al. "采用MFC压电作动器对复合材料悬臂板振动主动控制" . | 动力学与控制学报 15 . 4 (2017) : 342-349 . |
| APA | 李蒙 , 李凤明 . 采用MFC压电作动器对复合材料悬臂板振动主动控制 . | 动力学与控制学报 , 2017 , 15 (4) , 342-349 . |
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摘要 ：
研究了亚音速气流作用下不对称双跨黏弹性板的非线性振动特性.考虑von Kármán几何大变形,利用Hamilton原理,建立了不对称双跨黏弹性板的非线性运动方程,并对其采用分离变量法进行了离散.运用线性势理论得到了亚音速气流的气动压力表达式.利用板的边界条件和中间支承条件得到了双跨板的模态函数.研究了来流速度对双跨板非线性振动特性的影响,分析了不对称程度和黏弹性阻尼系数对结构发生混沌运动的影响.
关键词 ：
非线性振动 非线性振动 不对称双跨黏弹性板 不对称双跨黏弹性板 线性势流理论 线性势流理论 亚音速气流 亚音速气流
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| GB/T 7714 | 孟令常 , 李凤明 . 亚音速气流下不对称双跨黏弹性板的非线性振动特性研究 [J]. | 科学技术与工程 , 2017 , 17 (17) : 1-5 . |
| MLA | 孟令常 et al. "亚音速气流下不对称双跨黏弹性板的非线性振动特性研究" . | 科学技术与工程 17 . 17 (2017) : 1-5 . |
| APA | 孟令常 , 李凤明 . 亚音速气流下不对称双跨黏弹性板的非线性振动特性研究 . | 科学技术与工程 , 2017 , 17 (17) , 1-5 . |
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摘要 ：
多跨梁被广泛应用于实际工程中，例如厂房框架结构，铁轨，桥梁等，针对多跨梁结构振动问题的研究具有实际工程需求与研究意义。本文通过结构的横向位移与转角位移来构造多跨Timoshenko梁的位移场，应用Hamilton原理和假设模态法建立结构的运动方程。对多跨Timoshenko梁的横向位移应用三次插值函数表达，转角位移使用二次插值函数与三角函数级数两种方法进行表示，构造的插值函数满足结构边界条件。通过算例求解多跨Timoshenko梁结构的固有频率与单位脉冲激励下的自由振动时域响应，并与有限元软件ANSYS对照验证，分析了采用本文方法计算的结构固有频率与有限元结果的相对误差，算例中也同时验证了多跨Euler-Bernoulli梁的计算结果。进一步研究了失谐多跨梁的振动特性，分析了结构厚度和失谐度等参数对固有频率、振幅等振动特性的影响规律。通过算例分析与有限元验证，证明了本文计算方法的正确性，研究表明，在结构自身总长度不变、多跨梁在失谐度变化下，结构各阶固有频率的变化具有一定的规律性。
关键词 ：
多跨Timoshenko梁 多跨Timoshenko梁 插值法基 插值法基 固有频率 固有频率 假设模态法 假设模态法
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| GB/T 7714 | 赵召 , 李凤明 . 采用假设模态法研究多跨Timoshenko梁的振动问题 [C] //第十六届全国非线性振动暨第十三届全国非线性动力学和运动稳定性学术会议论文集 . 2017 : 1-1 . |
| MLA | 赵召 et al. "采用假设模态法研究多跨Timoshenko梁的振动问题" 第十六届全国非线性振动暨第十三届全国非线性动力学和运动稳定性学术会议论文集 . (2017) : 1-1 . |
| APA | 赵召 , 李凤明 . 采用假设模态法研究多跨Timoshenko梁的振动问题 第十六届全国非线性振动暨第十三届全国非线性动力学和运动稳定性学术会议论文集 . (2017) : 1-1 . |
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摘要 ：
发展了有限元方法,对超音速环境中梯形复合材料层合板的气动热弹性问题进行了研究.考虑可压缩流和斜激波的影响,采用一阶活塞理论表示气动压力.针对复合材料层合板的不规则结构,以及板由于气动加热而产生的复杂温度分布,利用有限单元法,建立梯形复合材料层合板的热传导方程和气动热弹性耦合运动方程.通过热传导方程得到板的温度分布,再结合气动热弹性运动方程分析梯形板的气动热弹性特性.通过数值计算,研究气动加热和铺设角对超音速下梯形板的固有频率和模态的影响.
关键词 ：
有限元分析 有限元分析 梯形复合材料层合板 梯形复合材料层合板 模态分析 模态分析 气动热弹性 气动热弹性 颤振 颤振
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| GB/T 7714 | 蒋国庆 , 李凤明 . 超音速下梯形复合材料层合板的气动热弹性 [J]. | 科学技术与工程 , 2017 , 17 (28) : 1-8 . |
| MLA | 蒋国庆 et al. "超音速下梯形复合材料层合板的气动热弹性" . | 科学技术与工程 17 . 28 (2017) : 1-8 . |
| APA | 蒋国庆 , 李凤明 . 超音速下梯形复合材料层合板的气动热弹性 . | 科学技术与工程 , 2017 , 17 (28) , 1-8 . |
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