层状弹性体系力学及其应用

层状弹性体系力学是弹性力学的一个分支。首先介绍层状弹性体系力学的发展历史。其次介绍$N$层弹性体系的力学分析与计算,内容包括基本假定、应力和位移分量的表达式、定解条件、根据定解条件建立求解积分常数的线性代数方程组、由线性代数方程组求解积分常数、贝塞尔函数的计算、积分计算公式、数值积分、后续的力学计算以及计算算例。最后介绍层状弹性体系力学在科学研究和工程设计中的应用。     

船舶声弹性力学理论及其应用

船舶结构与水介质耦合动力学在改善船舶运动性能与结构安全性,控制船舶振动噪声与提高水下声隐身性能,进行船舶综合性能的优化设计等一系列工程问题中有广泛的应用需求与发展前景.本文综述了船舶水弹性力学、声弹性力学的理论方法、试验技术与应用技术的国内外研究进展;介绍了在带航速三维水弹性力学理论(Wu 1984)基础上,作者所在课题组近年来发展的船舶三维声弹性理论、计算技术及工程应用的概况.简述了船舶三维声弹性理论的部分应用情况及发展方向.     

"2018流固耦合力学在船舶与海洋新能源中的应用研究领域科学家论坛"学术综述

简要介绍了 2018年1月召开的"2018流固耦合力学在船舶与海洋新能源中的应用研究领域科学家论坛"的基本情况,对邀请报告进行了分专题学 术综述,对专家们在自由发言和集中研讨中针对流固耦合力学在船舶与海洋新能源领域的应用提出的前瞻性关键科学问题及未来研究方 向的观点进行了归纳总结.      

力学的永恒魅力与贡献——————与时俱进的船舶力学

船舶力学是一个与船舶工程紧密结合的力学领域.作为力学的一门分支学科,于20世纪上半叶形成了自身较为系统的专业格局,并且在20世纪下半叶取得了突飞猛进的发展.结合当代船舶与船舶技术演进的概况,尤其是近年来超越传统的快速发展,简述了船舶力学所面临的需求及所做出的贡献.本文并对船舶力学主要研究领域的现状、发展方向与热点问题,择要作了概括的、远非全面的介绍,对其发展总趋势作了初步的分析.毫无疑问,船舶类型的每一步更新与发展,都包含着在船舶力学的领域中认识与把握船舶所遭受的随机、复杂、险恶的环境载荷,改进航行性能,保证船体安全可靠等方面的科学与技术的进步.凡是船舶力学研究最活跃的地方,往往就是需求最明确,船舶新技术出现最快的地方.可以说,现代船舶发展的历史,也就是船舶力学发展的历史,船舶力学是船舶技术创新的一个重要源泉,而船舶的工程需求又是船舶力学发展的基石,两者紧密结合,与时俱进.在人类的历史进入21世纪的时候,船舶设计制造技术频频更新,改变着船舶与海上运输的面貌,同时船舶力学发展的历史也将翻到崭新的一页.      

应用弹性力学理论计算水成膜泡沫灭火剂水膜厚度

应用弹性力学理论计算了水成膜泡沫灭火剂在油表面铺展水膜的厚度。假设油表面是一层不服从胡克定律的弹性膜,水膜在油表面的铺展厚度问题数学近似为半平面体在边界上受分布力问题,简化了应力公式,从而推导出了水膜厚度的计算公式。最后实验验证了计算公式的正确性。油表面铺展水膜的厚度在微米量级,且与水成膜泡沫灭火剂无关。     

极性材料的热弹性力学

本文在文献[1]、[2]、[3]、[5]、[7]的基础上,讨论了线性耦合下,极性材料三维热弹性力学的能量方程、熵生成定律、耗散函数、Fourier热传导方程和它的变分原理。     

各向异性弹性力学的研究进展

经典的弹性理论主要是研究均匀和各向同性的力学问题。自纳维和哥西在1820年提出弹性理论的基本问题开始,到十九世纪已形成了较为系统而完整的理论,典型的代表性文献是著名的Love著作。各向异性弹性力学的发展与生产发展紧密结合的,本世纪以来,随着航空工业的兴起,胶合木板等新型材料在工业上日益广泛的应用,刺激和推动了这个学科的发展。四十年代中期Lekhnitskii首先总结了苏联学者在三十年代对各向异性体的平面问题     

横观各向同性三维热弹性力学通解及其势理论法

通过引入两个位移函数，对用位移表达的运动平衡方程作了简化．利用算子理论，严格地导出了横观各向同性非耦合热弹性动力学问题的通解．对于静力学问题，通解的形式可进一步简化成用4个准调和函数来表示．具体考察了横观各向同性体内平面裂纹上下表面有对称分布温度作用的问题，推广了势理论方法，导出了一个积分方程和一个微分-积分方程．针对币状裂纹表面受均布温度作用情形，给出了具体的解。     

磁弹性、热磁弹性理论及其应用

介绍了磁弹性、热磁弹性的基本内容,发展简史,基本方程,理论研究,实际应用研究及其未来应用前景．      

数值计算在理论力学中的应用

过去编著理论力学书籍时,因计算机技术尚未得到广泛应用,故而迴避了用手算(包括借助计算尺及计算器)无法解答的问题,而实际上这类问题是很多的.在[1]的动力学部分有一个习题(15—24),要求的是质点的运动方程和轨迹方程.求解过程是大家所熟知的.如果问题引伸一下,要求求出质点在空中飞行的时间,则最终归结为求解一超越方程     

Advances in sono-elasticity of ships and the related applications

船舶结构与水介质耦合动力学在改善船舶运动性能与结构安全性,控制船舶振动噪声与提高水下声隐身性能,进行船舶综合性能的优化设计等一系列工程问题中有广泛的应用需求与发展前景.本文综述了船舶水弹性力学、声弹性力学的理论方法、试验技术与应用技术的国内外研究进展;介绍了在带航速三维水弹性力学理论(Wu 1984)基础上,作者所在课题组近年来发展的船舶三维声弹性理论、计算技术及工程应用的概况.简述了船舶三维声弹性理论的部分应用情况及发展方向.     

舰船尾部振动水弹性分析软件系统HDSS

介绍一个实用的舰船尾部振动水弹性分析软件系统,该系统基于流固耦合理论,针对舰船尾部结构特征,可以准确方便地预报出舰船尾部振动特性。系统还配有较强的后处理图形生成模块,可以形象逼真地绘制出振型图。     

流固耦合力学概述

本文简要介绍了流固耦合力学及其特点、研究分支、一些进展及进一步发展的趋势     

ODE conversion techniques and their applications in computational mechanics

In this paper, a number of ordinary differential equation (ODE) conversion techniques for transformation of nonstandard ODE boundary value problems into standard forms are summarised, together with their applications to a variety of boundary value problems in computational solid mechanics, such as eigenvalue problem, geometrical and material nonlinear problem, elastic contact problem and optimal design problems through some simple and representative examples. The advantage of such approach is that various ODE boundary value problems in computational mechanics can be solved effectively in a unified manner by invoking a standard ODE solver. The project is supported by National Natural Science Foundation of China.     

Nonlinear Dynamics of Mechanical Systems Under Complicated Forcing

This paper considers the problem of simple linear mechanical oscillators forced by complicated forcing functions, such as those induced by fluids or humans. Such problems arise in civil engineering in the design of bridges, grandstands and towers. The paper questions whether low dimensional models have much to contribute to the understanding of such problems, given the complicated possibilities of high-dimensional forcing.     

Prediction of the Compressible Stage Slamming Force on Rigid and Elastic Systems Impacting on the Water Surface

In this paper some models focusing on hydrodynamic and elasticforces arising during the impact of rigid and elastic systems on thewater surface are investigated. In particular, the supersoniccompressible stage of the impact is considered by modelling the slammingphenomenon through the Skalk–Feit acoustic approximation. The dynamicequations of the dropping system are coupled to those of the fluid and anonlinear fluid-solid interaction problem is stated. Generalrelationships between the body's shape, slamming force and body motionare determined. These equations are applied to the wedge water entrycases, and a closed-form expression for the maximum hydrodynamic forceis found. Moreover the theoretical correlation between the hydrodynamicforce and the body geometry allows us to control the inverse problem andthe shape associated to a constant slamming force is determined.Due to some simplifications allowed in the supersonic compressibleimpact, the results of the hydrodynamic analysis hold in closed form.This permits us to focus on the basic result of the paper addressed to asystematic correlation between hydrodynamic and elastic maximum forcesin terms of some characteristic dimensionless quantities involved influid-solid interaction.In particular, critical conditionscorresponding to those hydorelastic parameters combinations areinvestigated, leading to severe elastic response of the impactingsystem.     

A modal analysis for the dynamic response of fluid-structure systems

In this paper a theory of modal analysis for the dynamic response of fluid-structure systems is presented. A pair of generalized eigenvalue equations with three real symmetric matrices and their relationships are derived from the finite element equations in the form of structural displacements and fluid velocity potential. Generalized orthogonality relations of modal vectors are then developed. The response of the system to external excitation is derived in closed form by modal expansion. Two examples of the solution are given for illustration.     

Rayleigh Quotient, Ritz Method and Substructuring to Study Vibrations of Structures Coupled to Heavy Fluids: Potential of the Artificial Spring Method

The linear study of free vibrations of structures coupled to incompressible and inviscid fluids are studied by using the Rayleigh-Ritz method. The system is modelled by using different components. The artificial spring method is used to synthesise these components. The advantage is that admissible functions are defined in each component and the continuity condition of translational and rotational displacements between the rigid joints of the structure is no longer required. The fluid-structure interaction can be accurately described by using this method, including the effect of the free surface waves and the dynamic interaction among structural components via the fluid medium. An application of the method to a vertical circular tank partially filled with water is also presented in order to show the potential of the method. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the coupled vibration of an ideal fluid with a linear elastic structure

The purpose of this paper is to analyse theoretically and numerieally the coupled vibration of an ideal fiuid with a linear elastie structure.It is proved in the paper that the natural frequencies of the coupled vibration do exist and are all real positive. The paper presents an efficient method to transform a coupled fluid-structure system to the structure with added mass and the ribrational analysis of the former is replaced by the latter in vacuum only. Numerical solution is outlined for the transformed problem and a compact frequecy equation is derived in which fluid variables do not appear. This simplifies the analysis significanily. A convergent proof has been given to guarantee the reliability of the solution. The paper also offers a general algorithm combined with Ritz method, boundary element method, and finite element method to analyse the transformed problem. Based on this algorithm, one can apply a known structural analysing program, with a little modification, to solve many different kinds     

基于Fluent与Simpack的高速列车流固耦合联合仿真

基于列车系统动力学和高速列车空气动力学建立了高速列车流固耦合联合仿真计算方法。利用Fluent和Simpack分别计算高速列车气动特性和气动作用下的高速列车动力学性能,通过实时传递气动参数和姿态参数,实现高速列车流固耦合的联合仿真。利用建立的流固耦合方法研究了横风速度为10．7m／s时高速列车以350km／h速度运行时的流固耦合动力学行为。比较了离线仿真和联合仿真两种方法下列车气动力与姿态、安全性和舒适性指标的差异。研究表明,列车一气流的流固耦合效应对头车气动力和姿态的影响显著,头车安全性指标有所恶化。