Numerical Simulation of Brittle Damage in Concrete Specimens

A framework for damage mechanics of concrete is applied to simulate the nonlinear elastic deformation behavior of concrete using finite element method (FEM). A rather simple isotropic damage model containing essentially no adjustable parameters is shown to produce results in remarkably good agreement with sample experimental data: the damage law requires only the fracture energy to be defined completely. The model is achieved by introducing a damage surface that is similar to the yield function in the conventional theory of plasticity. A special form of damage surfaces is constructed to illustrate the application of the model. A new damage criterion, defined as an equivalent strain norm, is proposed, in order to take into consideration the asymmetric behavior of concrete. For verifying the FEM program including the model, deformations predicted by this model are compared with both the experimental ones for the concrete structural model and the ones calculated without application of the continuum damage mechanics.__________Translated from Problemy Prochnosti, No. 3, pp. 57 – 74, May – June, 2005.     

正切型弹性体材料的缓冲包装设计

提出一种利用正切型弹性体材料的力学数据进行缓冲包装结构设计的方法,对这种方法的原理进行详细的理论推导,得出计算缓冲垫结构尺寸的关系式。该关系式简单实用,设计出的缓冲衬垫具有最佳的理论缓冲效率。     

Computational homogenization of elasticity on a staggered grid

In this article, we propose to discretize the problem of linear elastic homogenization by finite differences on a staggered grid and introduce fast and robust solvers. Our method shares some properties with the FFT‐based homogenization technique of Moulinec and Suquet, which has received widespread attention recently because of its robustness and computational speed. These similarities include the use of FFT and the resulting performing solvers. The staggered grid discretization, however, offers three crucial improvements. Firstly, solutions obtained by our method are completely devoid of the spurious oscillations characterizing solutions obtained by Moulinec–Suquet's discretization. Secondly, the iteration numbers of our solvers are bounded independently of the grid size and the contrast. In particular, our solvers converge for three‐dimensional porous structures, which cannot be handled by Moulinec–Suquet's method. Thirdly, the finite difference discretization allows for algorithmic variants with lower memory consumption. More precisely, it is possible to reduce the memory consumption of the Moulinec–Suquet algorithms by 50%. We underline the effectiveness and the applicability of our methods by several numerical experiments of industrial scale. Copyright © 2015 John Wiley & Sons, Ltd.     

基于形参均匀B样条盈亏修正的图像边缘检测

利用形参均匀B样条平滑公式,建立了一种盈亏修正的图像边缘检测新方法。首先对图像的原型值点进行盈亏修正,进一步减少原始图像和平滑图像之间的残余误差;然后利用形参均匀B样条修匀公式对修正后的图像拟合光滑曲面;最后求拟合后的光滑曲面的一阶导数极值点或二阶导数的零交叉点作为边缘特征点。试验表明,该方法稳定可靠,精度较高,能够很好地去除伪边缘;同时该方法简洁,便于实时处理。     

改进型蚁群算法参数优化研究

研究在不使用局部搜索情况下参数组合对改进型蚁群算法的影响。以带时间窗的车辆路径问题为例,针对基于最大最小蚁群算法的改进蚁群算法中的五个参数,运用均匀设计法对最优参数配置问题进行了研究。仿真实验表明改进的蚁群算法效果明显,能有效解决Solomon数据集中的R类和RC类问题,且具有较强的鲁棒性。对最优参数的局部调整没有明显提高算法获取最优解能力的问题,分析了其可能的原因。     

广义非线性系统解的一致最终有界性研究*

首先利用隐函数定理及常规的非线性系统解地存在唯一性定理,给出了广义非线性系统解的存在唯一性条件,然后利用标量和Ｌｙａｐｕｎｏｖ函数方法,从系统本身出发,研究了广义非线性系统解的一致最终有界性。     

基于T-S模糊系统的软测量混合建模研究

在分析几种模糊系统建模方法的基础上，提出一种简单有效的软测量建模方法．该算法基于变结构构造法模糊建模思想，均匀设计模型的初始结构，以绝对误差为建模指标，通过增加模糊规则来提高T S模糊系统的精度．为降低规则参数辨识的计算量，提高建模速度，将规则参数分为线性和非线性两部分，分别采用Levenberg Marquardt法与最小二乘法进行辨识．实例证明，本文所提出的建模方法规则分布合理，收敛速度快，泛化性能好，适合建立多输入的软测量模型，具有较好的实际应用价值．     

MCP机制下考虑供需弹性的发电容量持留

统一出清的定价机制是电力市场中发电商存在持留行为的根本原因。针对电力市场设计中应考虑供需弹性的积极作用,该文分析了拥有边际机组的单个发电商容量持留行为发生的条件及其影响因素,并提出了将持留前后的购电费用之比作为衡量系统持留严重程度的指标W,算例验证,证明供需弹性可以作为制约发电商利用容量持留哄抬电价、危及市场稳定性的有力工具之一。     

潍坊电厂大管径风量测量装置的选型与应用

介绍了机翼和均速管流量计在目前火电厂应用的优缺点,以及它们之间的比较、安装、使用中应注意的事项。并以潍坊电厂超临界机组为例,介绍了一种新型风量测量装置——插入式多点风量测量装置的应用情况。     

基于企业门户统一认证系统的设计与实现

企业门户的统一身份认证可以解决多个系统独立认证的弊端,消除企业中的信息孤岛。文章根据企业中信息系统的特点和项目的时间和成本要求,对基于企业门户的统一认证系统进行了设计与实现,对其他企业门户项目中的相关工作具有一定的借鉴作用。