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Guided wave propagation in multilayered piezoelectric structures

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Science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 1094-1104页

作者： GUO YongQiang1, CHEN WeiQiu2,3.& ZHANG YongLiang4 1 key laboratory of Mechanics on Disaster and Environment in Western china, Ministry of Education, and School of {3. {3. and Mechanics, Lanzhou university, Lanzhou 73.000, china 2 key laboratory of soft soils and geoenvironmental engineering, Ministry of Education, and department of civil engineering, zhejiang university, hangzhou 3.0058, china 3.department of {3. Mechanics, zhejiang university, hangzhou 3.0027, china 4 School of {3. {3., Lanzhou Jiaotong university, Lanzhou 73.070, china key laboratory of Mechanics on Disaster and Environment in Western china Ministry of Education and School of Civil Engineering and Mechanics Lanzhou University Lanzhou China key laboratory of soft {3. and {3. engineering Ministry of Education and Department of Civil Engineering Zhejiang University Hangzhou China department of engineering Mechanics Zhejiang University Hangzhou China School of civil engineering Lanzhou Jiaotong University Lanzhou China

A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.

关键词： multilayered piezoelectric structures the method of reverberation-ray matrix guided waves dispersion characteristic

Analytical solution and semi-analytical solution for anisotropic functionally graded beam subject to arbitrary loading

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Science china(Physics,Mechanics & Astronomy) 2009年第8期52卷 1244-1256页

作者： HUANG DeJin1,2,DING HaoJiang1 & CHEN WeiQiu3.1 key laboratory of soft {3. and {3. engineering,Ministry of Education,zhejiang university,hangzhou 3.0027,china 2 Faculty of engineering,Ningbo university,Ningbo 3.5211,china 3.{13. of engineering Mechanics,zhejiang university,hangzhou 3.0027,china key laboratory of soft {3. and {3. engineering Ministry of Education Zhejiang University Hangzhou China Faculty of engineering Ningbo University Ningbo China department of engineering Mechanics Zhejiang University Hangzhou China

Analytical and semi-analytical solutions are presented for anisotropic functionally graded beams subject to an arbitrary load,which can be expanded in terms of sinusoidal *** plane stress problems,the stress function is assumed to consist of two parts,one being a product of a trigonometric function of the longitudinal coordinate(x) and an undetermined function of the thickness coordinate(y),and the other a linear polynomial of x with unknown coefficients depending on *** governing equations satisfied by these y-dependent functions are *** expressions for stresses,resultant forces and displacements are then deduced,with integral constants determinable from the boundary *** the analytical solution is derived for the beam with material coefficients varying exponentially or in a power law along the thickness,the semi-analytical solution is sought by making use of the sub-layer approximation for the beam with an arbitrary variation of material parameters along the *** present analysis is applicable to beams with various boundary conditions at the two *** numerical examples are presented for validation of the theory and illustration of the effects of certain parameters.

关键词： anisotropic material functionally graded arbitrary loading stress function analytical solution semi-analytical solution

折线形填埋场排水系统最大浸润线水位深度的计算

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土木工程学报 2011年第4期44卷 105-111页

作者：柯瀚陈云敏沈磊浙江大学软土和环境土工国家教育部重点实验室浙江杭州310027

在实际的填埋场设计中,存在着排水系统由两段或多段不同坡度的折线段组成的情况,目前对折线形排水系统最大水位深度的准确估算只适用于非常有限的几种情况。依据扩展的Dupuit假设,导出折线形排水系统在自由出流边界条件下的浸润线求解... 详细信息

在实际的填埋场设计中,存在着排水系统由两段或多段不同坡度的折线段组成的情况,目前对折线形排水系统最大水位深度的准确估算只适用于非常有限的几种情况。依据扩展的Dupuit假设,导出折线形排水系统在自由出流边界条件下的浸润线求解方法。通过案例分析及与Giroud等的计算结果比较,证明所提出的方法是合理和准确的。在此基础上,进行多参数分析。在一般情况下,下坡的最大液面高度取决于总长度、下游坡度及入渗强度。在计算上坡最大水头高度的时候,应该考虑由于下坡积水引起的上下坡交界处的水位。复合排水材料对减少最大水位深度有着重要的意义。

关键词：填埋场复合排水系统渗滤液最大水位深度

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基于模型试验的高铁路基动力累积变形研究

土木工程学报 2011年第6期44卷 112-119页

作者：边学成蒋红光申文明陈云敏浙江大学软弱土与环境土工教育部重点实验室浙江杭州310058 浙江大学岩土工程研究所浙江杭州310058

高速列车运行中的轮轴往复动荷载引起铁路线下结构产生累积变形,导致轨道平顺性变差,影响列车运行的舒适性和安全性,列车交通荷载引起的路基累积变形是高速铁路线路设计和运营维护中必须考虑的一个重要问题。基于残余应变模型建立了列... 详细信息

高速列车运行中的轮轴往复动荷载引起铁路线下结构产生累积变形,导致轨道平顺性变差,影响列车运行的舒适性和安全性,列车交通荷载引起的路基累积变形是高速铁路线路设计和运营维护中必须考虑的一个重要问题。基于残余应变模型建立了列车轮轴循环动荷载作用下路基填料和下卧层地基土体的累积变形计算方法;通过物理模型试验验证了该模型和计算方法的合理性,并确定了相应的关键参数取值方法,实验结果表明该模型参数具有较好的一致性。最后,通过将计算模型应用到具体的高速铁路线路动力沉降分析中,揭示了路基基床底层和地基累积变形的发展规律,分析了列车轴重和循环次数等主要控制因素的影响作用。

关键词：循环荷载路基填料地基土累积变形高速铁路

大型风电机组群桩基础受荷特性及长期累积沉降控制

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土木工程学报 2010年第3期43卷 75-80页

作者：任宇朱斌陈仁朋王振宇陈云敏浙江大学软弱土与环境土工教育部重点实验室浙江杭州310058 浙江大学建筑工程学院浙江杭州310058

大型风电机组基础顶部的巨大倾覆弯矩是其承受的主要荷载,该倾覆弯矩将转化为单桩顶部的竖向作用力。由于风的周期性,作用在风电机组群桩基础顶部的荷载具有明显的循环特性。循环荷载作用下风电机组基础将产生不均匀沉降并倾斜,因而累... 详细信息

大型风电机组基础顶部的巨大倾覆弯矩是其承受的主要荷载,该倾覆弯矩将转化为单桩顶部的竖向作用力。由于风的周期性,作用在风电机组群桩基础顶部的荷载具有明显的循环特性。循环荷载作用下风电机组基础将产生不均匀沉降并倾斜,因而累积沉降控制是风电机组基础设计中的关键问题之一。分析了风电机组及其群桩基础的受荷特点,计算了典型风电机组的桩顶循环荷载谱。通过桩基循环模型试验发现桩顶循环荷载比小于临界值λmin时,桩顶无累积沉降发生,因而保证风电机组循环荷载比小于该临界值则可较好地控制风电机组基础的长期不均匀沉降。根据试验结果建立了偏压条件下桩基累积沉降与循环次数的关系,用于预测风电机组基础的长期附加不均匀沉降。

关键词：风电机组基础循环荷载累积沉降

Modeling of multi-inclusion composites with interfacial imperfections: Micromechanical and numerical simulations

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中国科学:技术科学 2010年第2期 219-219页

作者： CHEN WeiQiu1, ZHU XingYi2 & HUANG ZhiYi2* 1 department of engineering Mechanics, Yuquan Campus, zhejiang university, {3. 3.0027, china 2 key laboratory of soft soils and geoenvironmental engineering, Ministry of Education department of civil engineering, Zijingang Campus, zhejiang university, hangzhou 3.0058, china

A micromechanical approach based on a two-layer built-in model and a numerical simulation based on boundary element method are proposed to predict the effective properties of the multi-inclusion composite with imperfect interfaces. The spring model is introduced to simulate the interface imperfection. These two methods are compared with each other, and good agreement is achieved. The effects of interface spring stiffness, volume ratio and stiffness of inclusions on the micro- and macro-mechanical behaviors of fiber-reinforced composites are investigated. It is shown that the developed micromechanical method is very comprehensive and efficient for fast prediction of effective properties of composites, while the numerical method is very accurate in detailed modeling of the mechanical behavior of composites with multiple inclusions.

关键词： micromechanics boundary element method interface multi-inclusion composite effective elastic property

MODELING OF MULTILAYERED ACOUSTIC WAVE DEVICES WITH THE METHOD OF REVERBERATION-RAY MATRIX

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MODELING OF MULTILAYERED ACOUSTIC WAVE DEVICES WITH THE METH...

第三届全国压电和声波理论及器件技术研讨会

作者： Yong-qiang GUO key laboratory of Mechanics on Disaster and Environment in Western china,Ministry of Education, and School of {3. {3. and Mechanics,Lanzhou university,Lanzhou 73.000,china Wei-qiu CHEN key laboratory of soft soils and geoenvironmental {3.,Ministry of Education,{13.,zhejiang university,hangzhou 3.0027,china

The method of reverberation-ray matrix(MRRM) are modified and extended to the analysis of wave propagation in multilayered acoustic wave devices based on three-dimensional linear *** the plane wave solution assumption,state equations are established whose solutions are expressed with unknown wave *** the framework of MRRM,the phase and scattering relations are properly set up to determine the unknowns without involving exponentially growing functions and matrix inversion operations in an easy and uniform *** the present MRRM is unconditionally stable and free from limitations to the frequency,the thickness of individual layers and the total number of *** surface waves,the interface waves and the bulk waves are all included in the formulation. Therefore,the present formulation applies to SAW devices as well as BAW *** examples are given to illustrate the well performance of the proposed formulation of MRRM for the analysis of free waves in multilayered acoustic wave devices.

关键词： Multilayered piezoelectric structures acoustic wave devices wave propagation method of reverberation-ray matrix

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无纺织物单向受拉时孔径变化研究

土木工程学报 2011年第S2期44卷 9-12页

作者：佘巍唐晓武张泉芳浙江大学软弱土与环境土工教育部重点实验室浙江杭州310058

现有反滤设计中保土准则使用土工织物未受拉时的等效孔径,但平面单向拉伸会导致该值变化,影响土工织物反滤性能。采用动力水筛法对三种无纺土工织物单向受拉时等效孔径变化进行测定。无纺织物被单向张拉至3.、5%和10%的平面应变,随着拉... 详细信息

现有反滤设计中保土准则使用土工织物未受拉时的等效孔径,但平面单向拉伸会导致该值变化,影响土工织物反滤性能。采用动力水筛法对三种无纺土工织物单向受拉时等效孔径变化进行测定。无纺织物被单向张拉至3.、5%和10%的平面应变,随着拉应变的增加,三种针刺无纺土工织物等效孔径减小。推求了无纺织物单向张拉时的等效孔径计算公式,对于较厚无纺织物,公式计算值和测试值较吻合,但对于较薄无纺织物,二值有一定差异。

关键词：无纺土工织物单向拉应变动力水筛法等效孔径孔径计算公式

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初始孔压特殊分布的饱和土一维热固结分析

绍兴文理学院学报(自然科学版) 2009年第4期 58-61页

作者：吴瑞潜马玉龙谢康和绍兴文理学院土木系绍兴综合工程勘察院浙江大学软弱土与环境土工教育部重点实验室

通过饱和土一维热固结方程的建立和求解,分别得到初始孔压3.特殊分布时的解析解.根据所得解编制了计算程序,分析并比较了3.初始孔压特殊分布的一维热固结性状.结果表明,当考虑温度影响时,热固结中超静孔压、沉降变化规律与传统固结理... 详细信息

通过饱和土一维热固结方程的建立和求解,分别得到初始孔压3.特殊分布时的解析解.根据所得解编制了计算程序,分析并比较了3.初始孔压特殊分布的一维热固结性状.结果表明,当考虑温度影响时,热固结中超静孔压、沉降变化规律与传统固结理论不同;在单面排水条件下,初始孔压正三角形分布时热固结最慢,倒三角形分布时热固结最快.

关键词：饱和土热固结解析解初始孔压特殊分布