Displacement Discontinuity Method for Fracture Mechanics Analysis of Reissner Plates: Static and Dynamic

This paper is concerned with the displacement discontinuity method applied to the shear deformable plates (Reissner’s and Mindlin’s theories) with cracks subjected to static and dynamic loads. Fundamental solutions of dislocation are derived using the Fourier transform method and the Laplace transformation technique. Boundary integral equations are presented in terms of rotations/displacement on the crack surfaces. The Chebyshev polynomials of the second kind are used to evaluate the integral equations with hypersingular kernels on the crack boundaries and determine the stress intensity factors at the crack tips. Comparisons are made with other numerical solutions to demonstrate the proposed method is accurate both for static and dynamic problems.     

小高层剪力墙结构开洞设计探讨

小高层建筑需通过剪力墙开洞(结构开洞)降低侧向刚度,本文对开洞部位以及墙肢和连梁设计提出一些看法,供设计人员参考。     

Azomesogens with 1,2,4-trisubstituted benzene moiety

New mesogenic homologous series having an azo central linkage was synthesized by fixing a rigid 4-methyl phenyl azo group to resorcinol moiety. The terminal and lateral phenolic -OH groups were esterified, one by one, with 4-n-alkoxybenzoyl and acetyl group, respectively. All the twelve homologues synthesized exhibit mesomorphism. The methoxy ton-decyloxy andn-hexadecyloxy derivatives exhibit monotropic nematic mesophase whereas,n-dodecyloxy andn-tetradecyloxy derivatives exhibit enantiotropic nematic mesophase. The mesogenic properties of the present series was compared with those of other structurally related mesogenic series. Paper presented at the 5th National Seminar on Liquid Crystals, University of Jammu, Jammu, December 1997.     

Mixed formulation of nonlinear beam on foundation elements

This paper presents an inelastic element for the analysis of beams on foundations. The element is derived from a two-field mixed formulation with independent approximation of forces and displacements. The state determination algorithm for the implementation of the element in a general purpose nonlinear finite element analysis program is presented and its stability characteristics are discussed. Numerical studies are performed to compare the model with the classical displacement formulation. The studies confirm the superiority of the proposed model in describing the inelastic behavior of beams on foundations.     

大块式动力基础的振动分析与加固处理

根据一大块式曲柄连杆机构的机器钢筋混凝土基础的振动测试与振动分析 ,诊断了基础发生工程事故的原因 ,并结合工程特点 ,在不改变基础设计的动力参数的情况下 ,确定了灌浆加固处理方法 ,并介绍了灌浆加固处理的效果。     

Pile Response Adjacent to Braced Excavation

The excavation of soil for the construction of basements or cut-and-cover tunnels results in ground movements. One particular concern is that the excavation-induced lateral soil movements may adversely affect any nearby pile foundation. The lateral loads imposed by the soil movements induce bending moments and deflections in the pile, which may lead to structural distress and failure. This paper presents the results of an actual full-scale instrumented study that was carried to examine the behavior of an existing pile due to nearby excavation activities resulting from the construction of a 16 m deep cut-and-cover tunnel. The pile was located 3 m behind a 0.8 m thick diaphragm wall. Excavation to the formation level that was 16 m below the ground surface resulted in a maximum lateral pile movement of 28 mm. A simplified numerical procedure based on the finite-element method was used to analyze the pile response. Generally, the theoretical predictions were in reasonable agreement with the measured results.     

DLL23XA双侧向测井仪的研制

以往双侧向测井仪动态范围小，测量精度低，为此开发了DLL23XA双侧向测井仪。该仪器主要单元采用厚膜电路，稳定性、一致性好；深、浅屏流源采用可变功率控制，提高了仪器的动态范围。仪器采用3506P例进行数据传输，可方便地配接各种地面系统。     

非对称复合材料层板在面内载荷作用下的非线性横向变形或屈曲

本文利用广义富里叶级数法对非对称复合材料层板在面内载荷作用下的非线性横向变形或屈曲问题进行了分析。文中主要研究了四边简支边界条件下,非对称层板的铺层方式和面内载荷形式对横向变形的影响。通过求解非线性控制方程得到了层板的载荷—挠度曲线或特殊情况下的后屈曲平衡曲线。计算结果表明,对于大多数非对称复合材料层板在面内载荷作用下所产生的是横向变形问题,而不是分叉屈曲问题。     

采用荷载平衡的概念表达预应力度及在初步设计中的应用

利用荷载平衡法的概念，将预应力度用等效荷载与外荷载的比值表达，设计可利用其比值确定预应力度，便其更简捷，明确，同时，提出了预应力度的真实值问题。     

对异常高压层厚度划分问题的探讨

通过对喇嘛甸油田800多口聚合物井、更新井的厚度划分及对15口井的异常高压层处理的实例，根据异常高压层在电测曲线上的反映特征，准确地将异常高压层识别出来，并采用本井上下相似层对比法、周围邻井砂体预测分析法、新老标准相结合法等综合分析判断方法，正确地划分异常高压层的厚度，将漏划或少划的厚度补划上。给后续的油层对比、水淹层解释、射孔方案的编制及动态、开发综合方案的调整提供准确的基础数据，并为套管损坏的防治、新钻井的异常高压层厚度解释提供了可借鉴的依据。