顺层边坡弯曲破坏的力学分析

本文对顺层边坡在纵向力和横向力联合作用下发生表层弯曲破坏现象进行了力学分析, 还推导了理论计算公式, 最后讨论了一个实例。     

船舶横向重力下水过程动力学分析

本文对现代船舶制造中的新工艺——船舶横向重力下水的动力学过程,作了详尽的理论分析与计算.编制了计算机软件,可供实际应用.     

矩阵摄动理论在六轴机车横向运动稳定性分析中的应用

本文提出了一种分析机车横向运动稳定性的方法,即利用复膜态的矩阵摄动法来计算临界速度,该方法避免了反复计算矩阵的特征值从而可节约大量的计算时间,对矩阵摄动法计算精度的研究结果表明,该方法的的精度是足够的。     

预应力混凝土箱梁横向框架效应有限元分析

以预应力混凝土箱梁桥顶板纵向开裂为工程背景,以箱梁顶板与腹板交接处两个角点的转角为基本未知量,基于箱梁纵向一维单元,利用最小势能原理推导出箱梁横向框架效应有限单元法的单元刚度矩阵,及相应的单元等效节点力,对比计算表明,该有限单元法计算精度与理论分析基本一致。实桥分析表明：现行规范计算箱梁角点弯矩相对安全,对于中点弯矩相对偏于不安全,设计过程不充分考虑混凝土箱梁横向框架效应可能导致顶板的纵向开裂。本文提出的有限单元法具有概念简单、运算速度快等优点,弥补了目前商业程序的不足,对工程设计具有一定的参考意义和推广价值。     

谐变磁场激励下非线性铁磁梁式板的共振分叉研究

本文采用磁场计算的磁体力理论模型,对处于均匀横向周期时变磁场中的非线性铁磁悬臂梁式板动力分叉问题进行理论分析和定量研究,首先建立了铁磁悬臂梁式板的非线性动力方程,在此基础上,采用非线性分析的多尺度法研究了铁磁悬壁板的共振分岔,最后,采用Floquet理论研究了该动力系统周期轨道的稳定性问题,数值给出了周期轨道的稳定性区域,Floquet理论研究了该动力系统周期轨道的稳定性问题,数值给出了周期轨道的稳定性区域,并分析了稳定区域与不稳定区域分界线上解的分叉情形。     

振荡流中圆柱受力测量研究

本文叙述了测量振荡流中圆柱受力大小和性质的方法和步骤。给出了测量结果,并首次给出这种力的频谱特性。     

裂纹轴局部柔度计算

本文介绍的分析--实验方法,定量地给出了横向裂纹对转轴局部刚度的影响,为高速转轴振动时,轴上裂纹复杂的开闭运动提供了一种较为精确的、具有普遍意义的力学模型,也为进一步研究裂纹轴横向振动特性打下基础.     

Reissner矩形板的弯曲问题

本文根据Rcissncr平板理论,提出了矩形中厚板弯曲问题的解答,应用本文中的(5)、(9)式,可求解通常边界条件下,承受横向均布力q_0以及承受横向均布力和板边法向弯矩等组合荷载共同作用下的矩形中厚板的弯曲问题,而且使这类问题的解答规律化。     

深水环境下隔水管的横向自由振动分析

隔水管是海洋钻井工程中的必要设备。在深水环境下,隔水管的疲劳失效问题普遍存在,隔水管的强烈振动是导致其失效的主要原因之一。本文采用微元法,得到了隔水管在各种载荷作用下的横向振动规律及其横向振动的固有频率的分布规律,进一步分析了各种因素对隔水管横向振动固有频率的影响。结果表明:隔水管的长度增加时,固有频率减小;随着顶部张力比的增加,隔水管的横向振动的固有频率也增加;随着壁厚的增加,隔水管横向振动的固有频率逐渐降低;而随着钻井液密度的增加,隔水管横向振动的固有频率增加;海水的存在使隔水管的横向振动固有频率降低。该研究有利于避免隔水管在使用过程中出现强烈的共振现象,为减小隔水管的失效提供了理论依据。     

极区间接横向惯性导航方法

针对极区经线收敛引起的以真北向作为航向参考的导航算法失效问题,在横向惯性导航方法的基础上,提出了一种以游移方位坐标系为导航坐标系的间接横向惯性导航方法,以寻求全球导航时算法的内在统一性,保证平台惯导平稳切换时的流畅性。在横向地球椭球模型下,推导了横向游移坐标编排,建立了误差模型,并进行了仿真分析,并给出了间接横向导航方法下的全球导航流程。结果表明,导航坐标系相同情况下指北编排与间接横向编排极区性能不同的本质原因在于游移角误差的不同;间接横向惯性导航方法能够满足极区导航与穿越极点航行要求,航向角误差小于0.1'/h。     

On the Representation of the Stored Energy for Elastic Materials with Full Transverse Response-Symmetry

We solve the representation problem for the stored energy of both transversely-isotropic and transversely-hemitropic elastic materials. Our method is based on giving the problem a form allowing application of a modified version of the classical representation theorem by Cauchy for scalar-valued mappings over the Nth power of a vector space. This revised version was published online in August 2006 with corrections to the Cover Date.     

复合材料迭层板弯曲分步分析法

本文提出了一种用于分析复合材料迭层板弯曲的新方法。首先利用经典理论进行初步分析,之后,据所得横向剪力,设定横向剪切应变,再进一步分析。本文方法基本未知函数少,基本方程易解,计算精度较高。     

Transverse vibrations of arbitrary non-uniform beams

Free and steady state forced transverse vibrations of non-uniform beams are investigated with a proposed method, leading to a series solution. The obtained series is verified to be convergent and linearly independent in a convergence test and by the non-zero value of the corresponding Wronski determinant, respectively. The obtained solution is rigorous, which can be reduced to a classical solution for uniform beams. The proposed method can deal with arbitrary non-uniform Euler-Bernoulli beams in principle, but the methods in terms of special functions or elementary functions can only work in some special cases.     

FINITE LAYER ANALYSIS FOR SEMI-INFINITE SOILS (Ⅰ)——GENERAL THEORY

In the present paper a finite layer method is studied for the elastodynamics of transverse isotropic bodies. With this method, semi-infinite soils can be considered as an transverse isotropic half-space, its material functions varying with depth. Dividing the half.space into a series of layers in the direction of depth the material fimetioms in each layer are simulated by exponential fumctions Consequently, the fundamental equations to be solved can be simplified if the fouricr transform with repsect to coordinates is used. We have obtained the relationship between the "layer forces" and "layer displacements". This finite layer method, in fact, can also be called a semi-analytical method. It possesses those advantages as the usual semi-analytical methods do, and can be used to analyse the problem of the interaction between soils and structures.     

复合材料模量细观分析的一般性模型

基于细观力学理论,提出了横观各向异性复合材料弹性常数的分析模型,并给出了纵向(纤维长度方向) 与横向弹性模量、横截面内剪切模量和泊松比等材料性能参数的理论推导和计算公式. 此方法简洁准确地反映了材料横观各向异性性能,改进了常规细观力学模型,也为工程分析提供了理论依据;同时在复合材料力学课程教学中,有助于深化学生对复合材料细观分析的理解,具有一定的启发性.     

SOLITARY WAVES IN FINITE DEFORMATION ELASTIC CIRCULAR ROD

A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes two nonlinear terms caused by finite deformation and double geometric dispersion effects caused by transverse inertia and transverse shearing strain. Nonlinear wave equation and corresponding truncated nonlinear wave equation were solved by the hyperbolic secant function finite expansion method. The solitary wave solutions of these nonlinear equations were obtained. The necessary condition of these solutions existence was given also.     

THE ESTIMATE AND MEASUREMENT OF TRANSVERSE WAVE INTENSITY

Transverse waves are a type of structural waves and should be considered in the analy-sis of high frequency vibration because the energy carried by transverse waves increases with the in-crease of frequency and becomes important at high frequencies. This paper studies the estimate theoryand measuring technique of the transverse wave intensity in two dimensional homogeneous structures.In general, the intensity vector is the sum of the effective intensity vector and the intensity variationvector. Each axial intensity component is proportional to two imaginary parts of cross spectral densitiesand its estimate is complicated. For the special case where transverse waves propagate in one direction,the intensity variation is zero and the estimate of the intensity is simplified. The intensity technique isformed based on the finite difference principle. Transverse wave intensity can be measured using a pairof two-transducer arrays lying in the orthogonal direction for the general case or a two-transducer ar-ray lying in the propagating direction for the special case. In order to assess the measurement accuracyof transverse wave intensity, the coupling loss factors from bending to transverse waves in buildingstructures were measured using the intensity technique and compared with the results predicted andmeasured using the conventional method. It is shown that the agreement between the results measuredusing the intensity technique and that by the conventional method is good.     

FINITE LAYER ANALYSIS FOR SEMI-INFINITE SOILS (Ⅰ)——GENERAL THEORY

In the present paper a finite layer method is studied for the elastodynamics of transverse isotropic bodies. With this method, semi-infinite soils can be considered as an transverse isotropic half-space, its material functions varying with depth. Dividing the half-space into a series of layers in the direction of depth, the material functions in each layer are simulated by exponential functions. Consequently, the fundamental equations to be solved can be simplified if the Fourier transform with repsect to coordinates is used. We have obtained the relationship between the “layer forces” and “layer displacements”. This finite layer method, in fact, can also be called a semi-analytical method. It possesses those advantages as the usual semi-analytical methods do, and can be used to analyse the problem of the interaction between soils and structures. This paper is based on a portion of the author's dissertation submitted in partial fulfillment of the requirements of degree of Ph. D. at the Shanghai Institute of Appl. Math. & Mech., Shanghai.     

765THE CUT-AND-TRY METHOD IN DETERMINING THE SATURATE SPACING OF TRANSVERSE CRACKS OF COMPOSITE LAMINATES

I.IntroductionTransversecracksfirstoccurinthe9o"plyandspreadalongtheentirewidth.Withstaticorcyclicloadadding,thenumberoftransversecracksinthepliescontinuous1yincreases,lastinguntilthedistributionofcracksreachesasaturatestate.Theoccurrenceoftransversecrack…