龙井水库大坝的渗流和稳定分析

本文以龙井水库大坝为例,运用有限单元法对粘土心墙坝的渗流进行分析计算,同时运用瑞典圆弧滑动法和简化Bishop法对粘土心墙坝的坝体稳定进行分析计算,在此基础上对水库大坝进行了渗流安全评价和稳定性安全评价。     

空腹式刚架拱桥梁拱节点三维光弹性试验研究

福州市尤溪洲闽江大桥是国内首座在拱肋（圈）上不设立柱和斜撑的空腹式刚架拱桥．作为空腹式刚架拱桥受力关键部位——梁与拱的连接部位，受力及构造复杂．通过三维光弹性试验，研究该梁、拱结合部的内力传递、应力集中、局部应力分布规律，为空腹式刚架拱桥节点设计、施工提供依据．     

建筑物爆炸泄压的试验研究

本文报导了在1米~3和30米~3两个爆炸泄压试验装置内进行的360余次试验结果。证明了在有平行壁面的建筑物内发生的可燃气爆炸泄压过程中,声动不稳定燃烧压力峰P3是建筑物的主要破坏因素。试验表明,本文发展的一种爆炸减压板具有消除P3的效应。     

某边坡变形破坏机理的数值分析

某花岗岩矿岩土体主要有填土、粉质粘土、淤泥及淤泥质土、含泥中粗砂、粘土、残积砂质粘土,其下为花岗岩基岩。边坡最大高度75m,其中残积土层以上的土质边坡高度约50m。本文运用有限元强度折减法对该边坡的稳定性进行了研究,得出了潜在的破坏模式及各个滑动部分的安全系数。分析结果表明,本边坡存在3个潜在滑动面,其中两个为浅层滑动面,另一个为深层滑动面。两个浅层滑动面的稳定系数在1.13～1.17,处于临界状态。深层滑动面稳定性系数在1.29,目前尚处在相对稳定状态。根据分析结果,提出了如下加固措施:（1）对滑坡体进行削坡处理;（2）在其滑动面下方设置抗滑台阶;（3）采用预应力锚索框架梁结合肋柱进行加固处理。     

复合材料结构的动力屈曲研究进展

本文系统地回顾了复合材料结构的动力屈曲研究进展，对周期性动载荷和瞬态动载荷作用下，复合材料结构的动力屈曲作了阐述；讨论了耦合效应，横向剪切变形、初始几何缺陷以及铺层方式等因素对动力屈曲的影响；就复合材料结构动力屈曲研究的发展前景提出了一些有益的建议     

地下水位上升下黄土斜坡稳定性分析

黄土高原一些地区,由于塬上引水灌溉使得地下水位不断抬升,造成黄土滑坡频繁发生。地下水位变化严重影响着黄土斜坡的稳定性。基于饱和-非饱和渗流理论和延伸的摩尔-库伦破坏准则,结合室内饱和和非饱和试验结果,针对泾阳南塬一典型黄土斜坡,考虑地下水位上升情况下,对其进行了瞬态饱和-非饱和渗流分析;然后将计算得到的瞬态孔隙水压力分布用于斜坡的极限平衡分析。结果表明:地下水位上升对暂态渗流场和斜坡稳定性有明显影响;考虑非饱和渗流和吸力强度的边坡稳定分析方法更加符合实际情况。     

ANALYSIS OF SYMMETRIC LAMINATED RECTANGULAR PLATES IN PLANE STRESS

Symmetric laminated plates used usually are anisotropic plates. Based on the fundamental equation for anisotropic rectangular plates in plane stress problem, a general analytical solution is established accurately by method of stress function. Therefore the general formula of stress and displacement in plane is given. The integral constants in general formula can be determined by boundary conditions. This general solution is composed of solutions made by trigonometric function and hyperbolic function, which can satisfy the problem of arbitrary boundary conditions along four edges, and the algebraic polynomial solutions which can satisfy the problem of boundary conditions at four corners. Consequently this general solution can be used to solve the plane stress problem with arbitrary boundary conditions. For example, a symmetric laminated square plate acted with uniform normal load, tangential load and nonuniform normal load on four edges is calculated and analyzed.     

Nodeless variable finite element method for heat transfer analysis by means of flux-based formulation and mesh adaptation

Based on flux-based formulation, a nodeless variable element method is developed to analyze two-dimensional steady-state and transient heat transfer problems. The nodeless variable element employs quadratic interpolation functions to provide higher solution accuracy without necessity to actually generate additional nodes. The flux-based formulation is applied to reduce the complexity in deriving the finite element equations as compared to the conventional finite element method. The solution accuracy is further improved by implementing an adaptive meshing technique to generate finite element mesh that can adapt and move along corresponding to the solution behavior. The technique generates small elements in the regions of steep solution gradients to provide accurate solution, and meanwhile it generates larger elements in the other regions where the solution gradients are slight to reduce the computational time and the computer memory. The effectiveness of the combined procedure is demonstrated by heat transfer problems that have exact solutions. These problems are: (a) a steady-state heat conduction analysis in a square plate subjected to a highly localized surface heating, and (b) a transient heat conduction analysis in a long plate subjected to a moving heat source. The English text was polished by Yunming Chen.     

工科基础课程考试命题设计的基本问题

现在,考试仍然是一种通用的评定学生学习成就的方法.当前关键的问题是要充分利用好这个"指挥棒"去促进教学内容和方法的改革,去引导学生在掌握知识,开发智力上发挥自己的主动性.为此,深入研究和探讨考试的命题设计问题,就显得迫切和重要了.     

桁架结构稳定分析的几何非线性欧拉稳定理论

目前,桁架结构稳定分析有两个理论:经典的特征值理论和几何非线性临界点理论。前者发展较早,在许多结构力学书中都有叙述。但是经过工程应用检验,它过高地估计了结构抗稳定的能力。后者是20年前提出的,提出者认为适用于所有的扁桁架。经过几年的研究,作者连续提出三个稳定理论:线性与非线性欧拉理论;非线性临界点-欧拉理论和两个计算方法,进行桁架结构的线性和非线性截面优化设计。经过理论研究和对前人文献中数值例题的计算和比较,发现特征值理论不符合实际,临界点理论只适用于大扁度的桁架,而不适用于一切扁桁架。研究结果提供了若干有用的结论,给出了各种稳定理论的适用范围,指出了国际文献中若干例题的正确和错误,补充了桁架结构的稳定分析理论,使之更为完整和实用了。