三维有限体中平片裂纹的超奇异积分方程方法—Ⅱ.数值方法

超奇异积分方程方法的理论分析已在本文的第Ｉ部分中给出，这一部分是经的数值方法，及用此方法求解的若干典型的平片裂纹问题。     

考虑疲劳裂纹扩展三维效应的James—Anderson修正方法

James-Anderson方法是一种借助材料疲劳裂纹扩展速率性能来确定三维裂纹应力强度因子的重要实验方法。本文对James-Anderson方法中的疲劳裂纹扩展三维效应进行了分析，并对其进行修正。修正后的James-Anderson方法考虑了疲劳裂纹扩展中由于应力状态而引起的三维效应。研究结果表明：和James-Anderson方法相比，修正后的James-Anderson方法得到的应力强度因子和三维数值方法所得的应力强度因子更吻合。     

BEHAVIOR OF OBSTRUCTED SQUARE BUOYANT VERTICAL JETS IN STATIC AMBIENT （Ⅰ）—— VERIFICATION OF MATHEMATICAL MODEL AND NUMERICAL METHOD

Some experiments were made for the buoyant jet from a square orifice with a square disc placed on it in static ambient and concentration along the axis in self-similar area behind disc was measured. And at the same time a three-dimensional mathematical model was established to simulate the whole flowing under different conditions. All the results predicted by the numerical calculation were substantiated by the experiments. The results were compared with experiential formula for obstructed round buoyant vertical jets in static ambient and it was found that the two concentration distributions had good accordance. Star shape of temperature isolines on cross-sections in the near areas from the disc was found and it was a very special figure for obstructed square buoyant vertical jets with a square disc. The shape will transform to concentric circles gradually alike to the round buoyant vertical jet in self-similar area with increasing of the distance from the disc.     

功能梯度材料板件三维分析的半解析梯度有限元法

将半解析有限元与梯度有限元相结合,形成一种半解析梯度有限元来求解功能梯度材料板件问题。该方法兼有有限元法的适应性强、程序统一,半解析有限元法的节省单元与计算工作量,梯度有限元法的适应构件内部材料性能任意梯度分布等特点,并实现用一维数值计算给出构件三维分析结果。算例分析表明了方法的精度、功能与上述特点,充分揭示了功能梯度材料板件力学响应的三维形态。半解析梯度有限元法可推广应用到其他功能梯度材料面结构的各类分析中。     

三维双材料结构的应力奇异性分析

应用有限单元法子模型技术，对具有不同界面角的三维双材料结构的应力奇异性进行了分析。结果表明，应用子模型技术估算三维双材料结构的应力奇异性指数是有效的。然后分析了界面端线和界面端点处附近奇异性指数，得到了一些重要而有趣的结果。最后对消除三维双材料结构应力奇异性的几何条件进行了讨论。     

弥散型核燃料元件热应力的计算模拟

针对弥散型燃料板的具体形状,选择了一种能够反映其实际变形特征的三维代表性体积单元作为研究对象;利用有限元法对其热力耦合行为进行了弹塑性分析,研究了热应力在燃料和基体中的分布特征.     

用迭代法模拟注塑成型的三维流动

Hele-Shaw模型是模拟注塑成型过程的常用模型,它的主要缺点是不能模拟一些重要的物理现象及引入实际制件中并不存在的“中面”概念,为了消除这些不足,本文开发了真三维的流动分析程序。建立了粘性、不可压缩的非牛顿流体流动的控制方程,为了避免同时求解耦合的压力场、速度场,本文引入拟稳定技术独立地求解这些方程,用迭代法求耦合方程的解。这种方法可以减少内存并提高数值方法的稳定性。算例表明数值结果与实验结果吻合较好,这种方法成功地模拟了注塑成型流动过程中的重要特征。     

Three-Dimensional Dynamic Contact Problem for an Elliptic Crack Interacting with a Normally Incident Harmonic Compression–Expansion Wave

The paper deals with the three-dimensional dynamic problem for an elliptic crack interacting with a normally incident harmonic compression–expansion wave, considering the contact interaction of the crack faces. An asymmetric solution is obtained using an iteration algorithm developed earlier. Numerical results are presented     

复杂三维结构物的光弹性实验研究

应用光弹性原理和方法，根据有关相似原理，对研究对象的几何尺寸进行缩比、模型设计及加工成型．然后将模型在危险载荷作用下，进行应力冻结、切片及应力分析．确定了模型不同截面上的应力及其变化规律，为优化设计和调整数值计算方法提供了有价值的依据．     

Plane Problem of Three-Dimensional Stability for a Hinged Plate with Two Symmetric End Cracks

The plane stability problem for a rectangular plate with two symmetric end cracks is solved in three-dimensional formulation. The three-dimensional linearized theory of stability and the finite-difference method are used. The effect of the crack parameter on the critical load is examined__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 4, pp. 47–52, April 2005.