钢筋混凝土结构在主余震作用下的概率累积损伤分析

本文利用我们在文献［１］中建立的主震与余震地面运动随机过程模型，以及在文献［２］中给出的带有负刚度段的三线性模型解析表达式，提出了钢筋砼结构在主震作用后，余震１作用下以及余震１作用后、余震２作用下的恢复力模型及其解析表达式；通过弹塑性随机地震反应分析，提出了结构在主震、余震１和余震２作用下的累积损伤模型及期望波损度与可靠性分析方法，最后给出了一两层钢筋砼框的算例。     

幂律流体两平行圆板间径向扩散层流进口段流动阻力的分析

在文献￣［２，３］的基础上，将其方法推广到幂律流体流动，首先导出幂律流体两平行圆板间径向扩散层流边界层的动量积分方程和能量积分方程。通过对动量积分方程的求解，对幂律流体的进口段长度以及进口段效应压力损失和流量修正系数进行了分析计算，并且讨论了幂律流体的流动指数ｎ与进口处修正雷诺数Ｒｅ＿１对进口段长度和压力损失系数的影响。特别是当ｎ＝１时，本文的解与文献￣［３］中的解完全一致，因而间接验证了本文结果的可靠性。     

具有记忆的污染物两维分散的描述

在污染物释放后的前期它的扩散过程受出口速度的影响而具有明显的记忆特性，本文将Ｒ．Ｓｍｉｔｈ［８］（１９８１）污染物纵向记忆描述理论推广到两维情况并给出了的解析表达式。     

弹性常数对薄板大挠度弯曲的影响

本文针对薄板大挠度弯曲问题，导出了不同弹性常数对应解之间的等价关系式，研究了弹性常数对横向荷载－挠度、弯曲应力－挠度、中面应力－挠度等非线性表达式系数的影响，还分析了文献［１］中近似换算公式的误差。     

层板脱层的能量释放率分析

含脱层的层板在承受压缩载荷作用时,很容易发生局部屈曲,导致脱层扩展和结构失效.本文利用可动边界变分问题对脱层扩展进行了分析,导出了脱层前缘各点处的能量释放率表达式.本文还对浅部椭圆脱层进行计算分析,指出:其能量释放率沿脱层边界有很大变化,脱层的扩展方向取决于脱层的形状、受载方式及铺层方向.     

复合材料多层板壳自振频率受迫振动及临界载荷的加权残数解

本文在文献［１］的基础上，将加权残数法用于求解复合材料多层板壳的自振频率、受迫振动及临界载荷，导出了相应的关系式。文中给出了算例并与解析解进行了对比。结果表明，本文方法简便，计算精度可以满足工程实际要求     

屈曲杆最大挠度近似公式的再改进

屈曲杆最大挠度近似公式的再改进朱华满（大连铁道学院大连１１６０２２）两端铰支细长压杆最大挠度近似公式已有多种形式￣［１－３］，精度较高、适用范围较大的当数文献［３］推荐的公式。本文导出的近似公式在精度和适用范围方面又有新的改进。欧拉从曲率精确式出发，...     

关于广义势

关于广义势唐其钏（中央民族大学物理系，北京１０００８１）一般分析力学中讨论的势函数ｕ与广义速度无关，称之为普通势。文献［１］、［２］、［３］给出了广义势的概念，利用它可以把分析动力学对机械运动的研究过渡到电动力学及相对运动。本文讨论什么样的广义力具有...     

复合曲梁中剪应力和径向应力的研究

文献［郾］讨论了复合曲梁在弯曲时的正应力问题，在此基础上，本文进一步导出了其剪应力和径向应力的计算公式，从而使复合曲梁的应力问题全部得到解决，作为特例，也可以从上述公式得到单层匀质曲梁的的相应公式，最后给出计算实例。     

纤维／基体界面裂纹扩展断裂能

本文通过研究纤维／基体界面裂纹断裂能，分析了几种界面脱粘断裂功的理论表达式；着重研究了单纤维拔出试验中界面残余压应力及界面摩擦对界面裂纹能量释放率的重要性．     

ENERGY RELEASE RATE COMPONENTS ANALYSIS OF LAMINATES WITH EMBEDDED DELAMINATION

This paper is the continuation of the authors' previous investigation inwhich the formula of total energy release rate at each point along the delaminationboundary iS derived by using variational method of moving boundary.In the presentpaper,the analytical model is reformed and the individual components of energyrelease rate are derived in the form of plate theory.The circular delaminationembedded in circular laminates is analysed and some conclusions are obtained.     

安全壳中钢衬壳热屈曲问题理论与实验研究(Ⅱ)──实验部分

钢衬壳热屈曲问题是核工程安全壳设计中的主要问题,但实验研究方面的文章发表得不多文中以200兆瓦核电站安全壳中钢衬壳为研究对象,采用局部1：1模型,测得了钢衬壳热屈曲温度和应变载荷,给出了钢衬壳屈曲和初始后屈曲过程中挠度和温度关系、以及膜应变和温度关系,实验测得钢衬壳具有局域屈曲的现象,实验屈曲载荷与理论结果符合较好     

Dynamic energy release rate expression for a spreading circular fracture pattern in a plate

An expression for the dynamic energy release rate of a spreading circular fracture pattern in an uniformly stretched plate is derived from a path-independent energy integral. This is equivalent to the energy dissipated in an incremental growth of a constant velocity circular locus in which the radial tension is zero. The relationship to rapid fracture and multiple crack division becomes apparent as the arc distance separating adjacent crack tips becomes small relative to the radius of the circular locus. The condition at some small fixed distance behind the closely spaced crack tips is then well-stimulated by that of zero radial tension on a circular locus. Experiments could be carried out to establish the accuracy of the analytical dynamic energy release rate expression for multiple crack division.     

STABILITY OF CIRCULAR RING OF CIRCULAR CROSS-SECTION UNDER UNIFORMLY DISTRIBUTED TORSION 1)

圆环在均布扭力矩作用下的变形特殊且容易发生跳跃,不考虑稳定性而得到的一些结论将可能不存在。本文利用最小势能原理导出圆截面圆环在均布扭力矩作用下的平衡路径,并根据系统稳定性的能量判据,对圆环的平衡稳定性、变形与运动过程进行分析,最后得到稳定平衡状态下圆环横截面上的内力最大值。     

热动力学理论在粘弹性断裂力学中的应用

本文基于热动力学定理推导了线性粘弹性材料的本构方程，并根据已有文献的思想列出了线性粘弹性材料的热力学平衡方程，由此推得二种全局能量释放率的表达开式，同时根据虚功原理进一步推得裂尖局部能量释放率，也就说明了全局能量释放率和被广泛应用的局部能量释放率之间的等价性，本文最后给出了在正交各向异性和向同性粘弹性介质中裂尖能量释放率的具体表达式。     

Anti-plane analysis of multiple cracks originating from a circular hole in a magnetoelectroelastic solid

The anti-plane problem of multiple cracks originating from a circular hole in a magnetoelectroelastic solid is investigated under remotely uniform anti-plane mechanical loading and in-plane electromagnetic loadings. The boundary value problem is reduced to a Cauchy integral equation by a new mapping function and the complex variable method, which is further solved exactly. The analytic expressions of the complex potentials, the field intensity factors and the energy release rate are derived in closed-form under the assumption that the surfaces of the cracks and hole are both electrically and magnetically impermeable. The effects of crack configurations and combined loadings on the energy release rate are shown graphically. Several useful results which may have potential applications to the design and fracture analysis of magnetoelectroelastic structures are given.     

SEMI-ANALYTICAL SOLUTION FOR TWO KINDS OF DELAMINATION MODELS OF LAMINATED CYLINDRICAL SHELLS

为了研究层合壳脱层,本文首先建立了柱坐标系下Hamilton 正则方程的8 节点等参元列式;然后分别采用了"先分后合" 模型和"弱粘接" 模型对开口壳的脱层损伤进行了模拟;通过利用层间的力学关系建立了整个壳的求解方程;最后分别从粘接完好和脱层两类情况对开口壳进行研究,并计算脱层前缘裂纹扩展的能量释放率. 数值实例的分析结果表明环向脱层受外载荷影响大于轴向脱层外载荷影响,脱层深度对两类脱层模型影响较大.     

轴对称压—弯下圆板中圆脱层的后屈曲扩展

本文分析了周边承受轴对称压一弯载荷的圆板中薄圆脱层的后屈曲扩展.运用基于四阶龙格-库塔积分公式的打靶法得到无量纲形式Von Karman非线性方程组的单参数解族.利用与路径无关的M积分导出能量释放率表达式并给出相应的数值解.文中还探讨了分叉、跳跃及扩展的可能性.     

压电体中考虑表面效应时开裂孔洞的断裂特征

研究了反平面机械载荷和面内电载荷作用下压电体中考虑表面效应时孔边双裂纹问题的断裂特征。基于Gurtin-Murdoch表面理论模型，通过构造映射函数，利用复势电弹理论获得了应力场和电位移场的闭合解答。给出了裂纹尖端应力强度因子、电位移场强因子和能量释放率的解析解。讨论了开裂孔洞几何参数和施加力电载荷对电弹场强因子和能量释放率的影响。     

Crack energy density and energy release rate for piezoelectric material

In this work, the concept of crack energy density (CED) was extended so as to be applied to piezoelectric material and its fundamental matters and properties were studied, and taking the knowledge about it into consideration, energy release rate for the material was newly derived. The definitions of CED, its mechanical and electrical contribution are given first and their path independent expressions are derived through the electromechanical energy conservation law. Subsequently, the loading path dependence of mechanical and electrical CEDs is discussed in detail. Some supplementary quantities related to CED and energy release rate are also defined and their path independent expressions are given. Energy release rate is derived through two opposite limit procedures, and the relations between energy release rate and other parameters are elicited through the discussions based on the fundamental properties of energy release rate.