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A General Method to Study the Sound Radiation of a Finite Cylindrical Shell Based on elastic theory

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Journal of Marine Science and Application 2012年第2期11卷 258-264页

作者： Junjie Zhang Chunhui Yuan Xianming Zhu Tianyun Li Huazhong University of Science and Technology Wuhan 430074 China National Key Laboratory on Ship I Tbration and Noise China Ship Development and Design Center Wuhan 430064 China

A general method was proposed to study the sound and vibration of a finite cylindrical shell with elastic theory. This method was developed through comprehensive analysis of the uncoupled Helmholtz equation obtained by the decomposition of elastic equations and the structure of the solution of a finite cylindrical shell analyzed by thin shell theory. The proposed method is theoretically suitable for arbitrary thickness of the shell and any frequency. Also, the results obtained through the method can be used to determine the range of application of the thin shell theory. Furthermore, the proposed method can deal with the problems limited by the thin shell theory. Additionally, the method can be suitable for several types of complex cylindrical shell such as the ring-stiffened cylindrical shell, damped cylindrical shell, and double cylindrical shell.

关键词： finite cylindrical shell elastic theory sound radiation thin shell theory

theory of nine elastic constants of biaxial nematics

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Chinese Physics B 2008年第3期17卷 1060-1069页

作者：刘红 School of Physical Science and Technology Nanjing Normal University

In this paper, a rotational invariant of interaction energy between two biaxial-shaped molecules is assumed and in the mean field approximation, nine elastic constants for simple distortion patterns in biaxial nematics are derived in terms of the thermal average （Dmn^（l））（Dm＇n＇^（l＇））, where Dmn^（l） is the Wigner rotation matrix. In the lowest order terms, the elastic constants depend on coefficients Γ,Γ＇, λ, order parameters Q0 = Q0（D00^（2））＋Q2（D02^（2）＋D0-2^（2）） and Q2 = Q0（D20^（2））＋ Q2（D22^（2）＋D2-2^（2））. Here Γ and Γ＇ depend on the function form of molecular interaction energy vj′j″j （τ12） and probability function fk′k″k （τ12）, where r12 is the distance between two molecules, and λ is proportional to temperature. Q0 and Q2 are parameters related to multiple moments of molecules. Comparing these results with those obtained from Landau-de Gennes theory, we have obtained relationships between coefficients, order parameters used in both theories. In the special case of uniaxial nematics, both results are reduced to a degenerate case where K11=K33.

关键词： biaxial nematic liquid crystal elastic theory

Efficient algorithm for 3D bimodulus structures

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Acta Mechanica Sinica 2020年第1期36卷 143-159页

作者： Qinxue Pan Jianlong Zheng Pihua Wen Key Laboratory of Road Structure and Material of Ministry of Transport(Changsha) School of Traffic and Transportation EngineeringChangsha University of Science&TechnologyChangsha410114China School of Engineering and Materials Science Queen Mary University of LondonLondonE14NSUK

The bimodulus material is a classical model to describe the elastic behavior of materials with tension-compression *** to the inherently nonlinear properties of bimodular materials,traditional iteration methods suffer from low convergence efficiency and poor adaptability for large-scale structures in *** this paper,a novel 3D algorithm is established by complementing the three shear moduli of the constitutive equation in principal stress *** contrast to the existing 3D shear modulus constructed based on experience,in this paper the shear modulus is derived theoretically through a limit ***,a theoretically self-consistent complemented algorithm is established and implemented in ABAQUS via UMAT;its good stability and convergence efficiency are verified by using benchmark *** analysis shows that the calculation error for bimodulus structures using the traditional linear elastic theory is large,which is not in line with reality.

关键词： elastic theory Bimodulus material 3D complemented algorithm Finite element method Generalized elastic law General 3D shear modulus

STUDIES ON STRESS TRANSFERENCE MECHANISM OF STEEL FIBRE REINFORCED CONCRETE

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Applied Mathematics and Mechanics(English Edition) 2001年第4期22卷 483-494页

作者：杨佑发许绍乾钟正华 College of Architectural Engineering Chongqing UniversityChongqing 400044 P R China Engineering Mechanics Department Hunan UniversityChangsha 410082 P R China

The stress transfer mechanism of steel fibre reinforced concrete is studied. The solutions for the stress and displacement were regarded as the superposition of ' the elementary solutions' and ' the improved solutions'. The elementary solutions were found by using two-dimensional elastic theory and the improved solutions were found by using the Love displacement function method. The calculated results indicate that the solutions possess good convergence. By comparing the three-dimensional solutions with the shear-lag solutions, evident difference may be found.

关键词： steel fiber reinforced concrete stress transference elastic theory