高层主裙楼变厚度桩筏基础数值试验

 提供了一种桩-土-筏相互作用的计算模型，将筏板下的桩、土看成弹簧作用在筏板上，简化得到了软弱地基群桩应力和沉降等效分析模型，提出了一种群桩中单桩沉降的计算方法，建立了群桩中单桩非线性刚度的计算模型，并采用三维退化层合单元法对高层建筑主裙楼桩筏基础进行分析．     

用实体退化板壳单元对立交桥进行空间分析

采用实体退化板壳单元对杭州复兴立交桥的单箱多室箱梁的结构进行空间分析,得出应力和挠度与试验结果相符,证明了实体退化板壳单元的正确性和有效性。     

基于退化理论的空间梁单元有限元分析

从双线性退化板壳单元出发,演绎推导出了一种可以应用于空间有限元分析的退化梁单元。退化梁单元采用基本的平截面假设,并用轴线节点位移来表示梁单元的三维位移场。在进行单元有限元列式时,仍然沿用三维结构的几何方程和物理方程。在退化梁单元的理论基础上编制了有限元计算程序,通过对几个算例的分析,证明了这种基于退化理论的空间梁单元的精确、高效和通用,这种单元也可以广泛应用于大型结构空间双重非线性有限元分析。     

基于区域叠合技术的三维编织复合材料渐进损伤过程数值模拟

基于区域叠合技术（DST）对编织复合材料渐进损伤过程进行了分析,利用ANSYS参数化设计语言建立了参数化的编织件模型,应用单元切割法在单元边与切割面交点处增加新的节点,将新增节点与该单元部分其他节点重构单元,实现从编织件模型中切割出增强相单胞模型。分别利用Hashin准则与Von Mises准则判断增强相损伤和基体损伤,根据相应损伤模式按修正的Blackketter刚度退化方案对材料刚度进行退化,应用适用于损伤分析的刚度匹配方法,实现区域叠合技术在编织复合材料渐进损伤分析中的应用。提出损伤结果映射方法,实现了基于区域叠合技术所建基体模型的渐进损伤过程的结果显示。数值分析结果发现,区域叠合法分析结果与传统方法分析结果一致,且强度和断裂应变预测结果与试验结果相吻合。     

基于GPU并行计算的地下结构非线性动力分析软件平台开发

为解决地下结构隐式非线性动力分析收敛性差和计算效率低的技术瓶颈,该文建立了基于GPU并行计算的地下结构显式动力分析软件平台。在此平台中提出并实现了一种混凝土弥散开裂模型;给出并实现了一种钢筋纤维与实体单元的耦合方法;基于等参元思想,提出了人工边界节点的单元从属面积的计算方法;为实现节点不协调情况下的土与结构相互作用分析,开发实现了一种实体单元间的两节点接触单元。利用该文开发的软件对日本大开地铁站进行了重力场分析、线性和非线性动力分析。将重力场和线性动力分析结果与ABAQUS分析结果进行了对比,结果表明该文软件计算结果与ABAQUS计算结果一致,且计算效率约为ABAQUS计算效率的5.68倍,验证了软件各模块的正确性和效率。另外,通过将非线性计算结果与灾害调查结果进行对比分析,验证了软件非线性分析的稳定性和合理性。     

基于退化梁单元的混凝土结构徐变分析

应用退化梁单元分析了混凝土结构的徐变问题。在实际混凝土结构中,混凝土结构的徐变与混凝土开裂等非线性行为存在相互耦合作用。退化梁单元采用了三维结构的几何和物理方程,结合分块积分技术,可以方便地模拟钢筋混凝土结构的各种非线性行为。应用Trost-Bazant方法,建立了退化梁单元混凝土结构徐变分析计算方法。算例分析表明了计算结果的正确及在实际混凝土结构徐变分析中计入非线性行为的必要性。     

三维实体退化虚拟层合梁单元在钢曲梁极限承载力分析中的应用

提出采用三维实体退化虚拟层合梁单元计算钢曲梁极限承载力的方法。考虑结构的几何非线性和材料非线性,利用该单元编制了极限承载力计算程序,并将其应用于钢曲梁极限承载力的分析。计算实例表明,该单元收敛快,稳定性好,在单元数较少的情况下,具有较高的精度。由于能克服壳体单元或梁段单元法的缺陷,该计算方法具有更强的通用性。     

基于实测值的桩基沉降计算方法对比分析

以天津滨海地区桩基工程实测资料为基础,应用MATLAB软件编制桩基沉降计算程序,分别用等效作用分层总和法和等代实体深基础法计算桩-承台基础沉降,用明德林法计算桩筏基础沉降。分析表明:等效作用分层总和法计算值小于实测值,而实体深基础法和明德林法则基本大于实测值。分析结果可为3种沉降计算方法在天津滨海地区桩基工程中的应用提供参考。     

混杂CFRP/GFRP筋HPC梁的非线性梁壳组合单元研究

对于混杂CFRP/GFRP筋高性能混凝土（HPC）梁, 研究一种新的三维非线性梁壳组合单元, 对HPC梁进行了全过程分析。引入实体退化壳单元理论, 利用空间梁单元模拟预应力CFRP筋, 并根据CFRP筋单元节点线位移和转角位移的协调性, 推导CFRP筋单元对梁壳组合单元刚度矩阵的贡献, 同时对GFRP筋和HPC梁采用分层壳单元模拟。并运用Jiang屈服准则、 Madrid强化准则等描述混凝土的材料非线性, 提出一种新的非线性梁壳组合单元, 研制相应的三维非线性计算程序。计算结果与试验数据吻合良好, 说明本文构造的非线性梁壳组合单元的正确性和研制程序的可靠性, 以及混凝土材料非线性描述的合理性; 采用组合单元能准确模拟CFRP筋的几何构形, 能综合考虑其拉压弯剪性能, 利于全面地反映配筋对结构的增强作用。      

一种有限元结构动态计算的过渡元──9节点板壳－实体元

本文利用三维八节点实体元和八节点由壳超参数单元构造出一种９节点板壳－实体过渡元。该元具有三维实体和曲壳的双重属性。可用于一些板壳－实体结构的动态计算。由于该元要求与之相联的实体，板壳元网络划分简单，单元结点数较少，动态计算精度能满足工程精度要求，所以该元具有一定的实用价值。     

实体退化板单元及其在板的振动分析中的应用

经典板壳单元是由板壳理论构造出来的,而经典的板壳理论是在空间弹性理论的基础上考虑板壳的基本假定得来的。在空间等参数单元的基础上,直接引入板壳的基本假定,修改空间等参数单元的弹性矩阵,从而构造出适合于厚薄板壳分析的20结点实体退化板单元,并将其应用于开口圆柱薄壳的静力分析和厚薄板的固有振动分析。数值算例表明,该单元收敛快,稳定性好,具有较高的精度。此外,该单元还可以用于曲边变厚度板、壳体及层合板的振动分析。     

Buckling response of laminated composite stiffened plates subjected to partial in-plane edge loading

This article presents the buckling analysis of laminated composite stiffened plates subjected to partial in-plane edge loading. The finite element method is used to carry out the analysis. The eight-noded isoparametric degenerated shell element with C⁰ continuity and first-order shear deformation and a compatible three-noded curved beam element are used to model the plate skin and the stiffeners, respectively. The eigen value analysis is carried out to track the buckling load. The convergence study is performed for some specific problems and the results are compared with the available results in the literature. It is observed that the convergence of results is very fast for this finite element model. Effect of different parameters like orientation of fibers, number of layers, and loading types are considered in the present investigation. It is also observed that all these parameters have significant effect on the buckling response of the composite stiffened plate.     

采用面积坐标的四边形厚薄板通用单元

本文采用四边形面积坐标,利用假设剪切应变场方法和广义协调理论构造出一个具有12个自由度的四边形厚薄板通用弯曲单元TACQ。基本思路如下：首先从Mindlin厚板理论出发,独立假设剪应变场和挠度场,而转角场则由挠度场和剪应变场导出;其次,单元剪应变场是先按Timoshenko厚梁理论确定单元各边剪应变,然后在单元内进行合理插值导出;第三,单元挠度场是根据单元角点处挠度的点协调条件以及单元各边挠度和法向转角的平均协调条件导出。这个方法有两个特点,（1）由于满足点协调和边协调的广义协调条件,故能保证收敛;（2）由于在薄板情况剪应变退化为零,故不出现剪切闭锁现象。数值算例表明：该单元具有精度高,收敛性和可靠性好,对网格畸变不敏感,无剪切闭锁现象等优点;适用于从极薄板到厚板较大的范围。     

非协调实体退化厚/薄板单元

在八节点三维实体等参元基础上,将板理论基本假定引入弹性应力-应变矩阵,并为局部坐标系下的挠度位移分量附加非协调位移项,构造了非协调实体退化板单元。板假定的引入用以克服单元厚度泊松自锁,非协调项的引入可缓解单元剪切自锁。通过修正常应变矩阵,确保单元通过分片检验。分域积分方法的采用,使单元可用于层合板结构分析。算例表明:单元对等厚度的厚/薄板均适用。     

A boundary/domain element method for analysis of building raft foundations

In this paper, a new boundary/domain element method is developed to analyse plates resting on elastic foundations. The developed formulation is then used in analysing building raft foundations. For more practical representation, the considered raft plate is treated as thick plate with free edge boundary conditions. The soil or the elastic foundation is represented as continuous media (follows the Winkler assumption). The boundary element method is employed to model the raft plate; whereas the soil is modelled using constant domain cells or elements. Therefore, in the present formulation both the domain and the boundary of the raft plate are discretized. The associate soil domain integral is replaced by equivalent boundary integrals along each cell contour. The necessary matrix implementation of such formulation is carried out and explained in details. The main advantage of the present formulation is the ability of analysing rafts on non-homogenous soils. Two examples are presented including raft on non-homogenous soil and raft for practical building applications. The results are compared with those obtained from other finite element and alternative boundary element methods to verify the validity and accuracy of the present formulation.     

Refined discrete quadrilateral degenerated shell element by using Timoshenko's beam function

A refined discrete degenerated 20‐DOF quadrilateral shell element RQS20 is proposed. The exact displacement function of the Timoshenko's beam is used as the displacement on the element boundary. The re‐constitute method for shear strain matrix is adopted. The proposed element can be used for the analysis of both moderately thick and thin plates/shells, and the convergence for the very thin case can be ensured theoretically. Numerical examples presented show that the new model indeed possesses higher accuracy in the analysis of thin and thick plates/shells, and that it can pass the patch test required for the Kirchhoff thin plate elements. Most important of all, it is free from the membrane and shear locking phenomena for extremely thin plates/shells, on the one hand, and it can also avoid the phenomenon of oscillatory solutions for thick plates/shells case on the other. Copyright © 2005 John Wiley & Sons, Ltd.     

复合材料加筋层合板的极限强度分析

基于更新拉格朗日格式,应用非线性层合三维退化壳元,结合有效的复合材料失效准则、刚度退化模型以及提出的刚度矩阵奇异判断准则,对复合材料加筋层合板在轴向载荷作用下的压缩极限强度问题进行深入研究。讨论了铺层方式、板厚等对极限强度的影响。通过与试验结果进行比较,表明基于提出的刚度矩阵奇异判断准则,结合增量更新拉格朗日格式下非线性层合三维退化有限元的计算方法,能有效计算复合材料加筋层合板的轴向压缩极限强度,并具有很高的精度。     

Hybrid displacement function element method: a simple hybrid‐Trefftz stress element method for analysis of Mindlin–Reissner plate

In order to develop robust finite element models for analysis of thin and moderately thick plates, a simple hybrid displacement function element method is presented. First, the variational functional of complementary energy for Mindlin–Reissner plates is modified to be expressed by a displacement function F, which can be used to derive displacement components satisfying all governing equations. Second, the assumed element resultant force fields, which can satisfy all related governing equations, are derived from the fundamental analytical solutions of F. Third, the displacements and shear strains along each element boundary are determined by the locking‐free formulae based on the Timoshenko's beam theory. Finally, by applying the principle of minimum complementary energy, the element stiffness matrix related to the conventional nodal displacement DOFs is obtained. Because the trial functions of the domain stress approximations a priori satisfy governing equations, this method is consistent with the hybrid‐Trefftz stress element method. As an example, a 4‐node, 12‐DOF quadrilateral plate bending element, HDF‐P4‐11 β, is formulated. Numerical benchmark examples have proved that the new model possesses excellent precision. It is also a shape‐free element that performs very well even when a severely distorted mesh containing concave quadrilateral and degenerated triangular elements is employed. Copyright © 2014 John Wiley & Sons, Ltd.     

基于平面弹性-板弯曲比拟理论的Wilson型板弯曲单元

应用平面弹性板弯曲比拟关系,可以避开1c连续性的困难,为板单元的构造提供了一种新的途径。这一新方法已成功地将一些平面弹性协调单元转化为新型板弯曲单元。根据比拟理论将著名的平面弹性Wilson元QM6转化为板弯曲单元,从而将新方法应用到平面弹性非协调元。单元构造简单,数值结果表明具有很好的收敛性和精度。