基于事例学习的建筑结构的虚拟实现

提出基于事例学习的目标规划问题,并进一步研究了建模思想的可行性和建模方法的可操作性。利用知识工程、机器学习理论,人工智能技术来存贮和运用专家的经验,实现了在虚拟环境中建筑结构设计、施工,设备的仿真试验,并可对初学者或尚无经验的设计、施工者进行培训学习。该项研究为目标规划问题开辟了基于事例学习的模型生成途径。     

Allowables-Based Flow Curves for Nonlinear Finite-Element Analysis

A methodology for developing allowables-based stress versus strain relationships for metal alloys is presented. The approach incorporates Federal Aviation Administration/Department of Defense (FAA/DoD) Metallic Materials Property Development and Standardization (MMPDS) statistically derived material properties for tensile yield and ultimate strengths to derive flow curves at room or elevated temperature with an A-, B-, or S-Basis probability. The resulting flow curves may be used for new designs to comply with Federal Air Regulations as well as for forensic investigations and failure analysis.     

汪藕裳年谱

汪藕裳,清代著名弹词女作家,著有《子虚记》、《群英传》等作品。现存各种文学工具书对其生平事迹均无记述。现根据汪氏家谱、方志及汪氏后人口述史料,首次以年谱的形式,较为全面地整理出她的家世、生平、交游及作品的产生、传播及评介等资料。     

Optimization of a plate with holes

We consider a simply supported plate with constant thickness, defined on an unknown multiply connected domain. We optimize its shape according to some given performance functional. Our method is of fixed domain type, easy to be implemented, based on a fictitious domain approach and the control variational method. The algorithm that we introduce is of gradient type and performs simultaneous topological and boundary variations. Numerical experiments are also included and show its efficiency.     

浅谈网上虚拟实验室的构建

本文从理论层面讨论了虚拟实验室的基本概念．功能定位和主要特点．在此基础上阐述了虚拟实验室构建的基本原则和方法。     

粘性流场中固体颗粒启动和沉降过程的直接数值模拟

利用多重网格虚拟边界有限元法（multigrid fictitious boundary method，MFBM），对粘性流场中固体颗粒的启动和沉降过程进行直接数值模拟。在计算过程中，计算网格是固定的多重结构有限元网格，固体颗粒可自由通过网格而无需重新生成网格。流体运动由Navier-Stokes方程控制，固体颗粒运动由Newton-Euler方程控制，用MFBM处理流体与固体颗粒的相互作用。通过对单个固体颗粒和多个固体颗粒启动和沉降过程的数值模拟，表明MFBM提供了一个数值模拟颗粒启动和沉降问题非常有效的途径。     

A topological derivative method for topology optimization

We propose a fictitious domain method for topology optimization in which a level set of the topological derivative field for the cost function identifies the boundary of the optimal design. We describe a fixed-point iteration scheme that implements this optimality criterion subject to a volumetric resource constraint. A smooth and consistent projection of the region bounded by the level set onto the fictitious analysis domain simplifies the response analysis and enhances the convergence of the optimization algorithm. Moreover, the projection supports the reintroduction of solid material in void regions, a critical requirement for robust topology optimization. We present several numerical examples that demonstrate compliance minimization of fixed-volume, linearly elastic structures.     

钢笔画在学习和工作中的重要性

在现在学习和工作中,钢笔画有助于提高我们的技法表现、形式处理、审美创造能力和艺术修养.     

弹塑性结构的动力学塑性变形的上界

本文借助于虚载荷方法讨论了弹性完全塑性结构在动载荷下塑性变形的上界问题,结出了塑性变形的上界估计式.同时,在假设分段线性加载面的情况下,将结果推广到线性强化结构.此外,本文还给出一例,将所得结果与精确解进行了比较,表明本文的结果有较大的实用价值.