Triangular element partition method with consideration of crack tip

In fracture simulation,how to model the pre-existing cracks and simulate their propagation without remeshing is an important topic.The newly developed triangular element partition method(TEPM)provides an efficient approach to this problem.It firstly meshes the cracked body regardless of the geometry integrity of the interesting object with triangular elements.After the meshing procedure is completed,some elements are intersected by cracks.For the element intersected by a crack,the TEPM takes the element partition technique to incorporate the discontinuity into the numerical model without any interpolation enrichment.By this approach,the TEPM can simulate fracture without mesh modification.In the TEPM,all the cracked elements are treated as the usual partitioned elements in which the crack runs through.The virtual node pairs(the intersection points of crack faces and elements)at the opposite faces of the crack move independently.Their displacements are respectively determined by their neighbor real nodes(nodes formatted in the original mesh scheme)at the same side of the crack.However,among these cracked elements,the element containing a crack tip,referred to as the crack tip element thereafter,behaves differently from those cut through by the crack.Its influence on the singular field at the vicinity of the fracture tip becomes increasingly significant with the element size increasing.In the crack tip element,the virtual node pair at the crack tip move consistently before fracture occurs while the virtual node pair separate and each virtual node moves independently after the fracture propagates.Accordingly,the crack tip element is automatically transformed into the usual partitioned element.In the present paper,the crack tip element is introduced into the TEPM to account for the effect of the crack tip.Validation examples indicate that the present method is almost free from the element size effect.It can reach the same precision as the conventional finite element method under the same meshing scheme.But the TEPM is much more efficient and convenient than the conventional finite element method because the TEPM avoids the troubles that the conventional finite element method suffers,e.g.,the meshing problem of cracked body,modification of mesh scheme,etc.Though the extended finite element method can also avoid these troubles,it introduces extra degrees of freedom due to node interpolation enrichment.Due to the simplicity of the present TEPM,it is believed that its perspective should be highly inspiring.     

Bi2WO6粉体光催化剂的制备方法及研究进展

光催化技术因其在环境污染净化、能源再生方面的应用前景而引起了广泛关注,新型光催化剂钨酸铋因其具有可见光催化活性成为了光化学领域的研究热点之一．作者简述了Bi2WO6粉体光催化剂的结构及光催化性,详细介绍了一些Bi2WO6粉体的制备方法,总结了Bi2WO6粉体光催化剂今后的研究方向与热点,可为有关人员提供参考．     

模糊数学综合评判法在菜肴感官评定中的应用——以川菜代表性菜肴鱼香肉丝为例

感官评定是控制烹饪菜品质量的重要途径之一,文章以川菜代表性菜品——鱼香肉丝为评定对象,选取色、香、味、形、质等因素并设置合理的权重,对同一试验小组A、B、C、D、E等5道鱼香肉丝菜肴进行模糊数学综合评定。试验结果表明,用模糊数学综合评判法,能客观而准确地区分出不同烹饪菜肴的差异程度和等级,即5道鱼香肉丝感官评定等级从高到低为：C〉D〉E〉A〉B。     

高职教师教学研资源管理与考核系统的研究

针对高职教师教学研管理人工考核弊端,指出了高职教师教学研资源管理和考核系统建立的必要性,整体设计高职教师教学研资源管理和考核系统的组织结构,结合教师工作特点,重点构建高职教师教学研考核指标体系,最后讨论了系统实现的技术流程,为信息化的高职教师教学研管理好考核系统设计与实现奠定了基础。     

基于动态BP网络的实验电炉温度控制系统

针对一类不允许出现超调的工艺参数,提出了采用动态BP网络对工艺参数进行控制,可以达到良好的效果。并以实验电炉为对象,用工控机对其炉温进行控制,结果表明,采用动态BP网络进行控制,可以无超调地无限逼近给定值,控制精度高,控制时间较短。因此可以认为,用动态BP网络对这一类工艺参数的控制是有效的。     

Study of Quintic Spline Interpolation and Generated Velocity Profile for High Speed Machining

Modern high speed machining (HSM) machine tools often operates at high speed and high feedrate with high ac- celerations,in order to deliver the rapid feed motion.This paper presents an interpolation algorithm to generate continuous quintic spline toolpaths,with a constant travel increment at each step,while the smoother accelerations and jerks of two-order curve are obtained.Then an approach for reducing the feedrate fluctuation in high speed spline interpolation is presented.The presented ap- proach has been validated to quickly,reliably and effective with the simulation.     

一类非光滑非凸分式半无限规划的最优性

在一致Fb-凸函数，一致Fb-伪凸和一致Fb-拟凸等广义凸性函数的基础上，研究了一类分式半无限规划问题，得到了涉及这些广义凸性函数的一类非光滑分式半无限规划的一些最优条件。     

浅谈音乐教学中相关知识的融汇贯通

音乐、文学、美术，从古至今它们之间一直都有着千丝万缕的联系，相互影响，共同发展,利用音画交融，视听互补；通过作词荐曲，学科互补，可提高音乐教学质量，并能有效地培养学生的创造性思维。     

介孔分子筛孔尺寸表征方法比较

MCM-41是由表面活性剂十六烷基三甲基溴化铵为模板剂经水热合成，550℃煅烧5h制备的规则硅质六方介摘要孔材料；Ti-MCM-41是在MCM-41的基础上，将Ti离子涂敷引入到MCM-41的介孔中合成的。该类材料孔尺寸的表征方法有N2吸附、透射电镜TEM、SAXS等，其中N2吸附、透射电镜是传统的介孔尺寸的表征方法，SAXS是近年新的介孔尺寸的表征方法。比较了Ti-MCM-41材料的孔尺寸的表征方法，得出：SAXS得到的Ti-MCM-41孔径与TEM照片的结果符合较好，但与N2吸附的结果偏差较大。SAXS、TEM、N2吸附-脱附等温线给出的Ti-MCM-41的平均孔径分别为2.00nm、2.15nm、3.60nm。     

用于MIS的实时数据共享软件平台的设计与实现

电网企业的各种信息,相互间具有相当紧密的关联关系,这些信息关联的核心就是电网实时数据。将电网实时数据引入到管理信息系统(MIS)中,使管理信息系统能够有效的分析利用实时数据对于促进电力系统的信息化发展具有重要意义。本文详细的阐述了用于管理信息系统(MIS)的电网实时数据共享软件平台的系统结构、工作原理以及设计与实现,提出了解决电网企业生产网和管理网信息共享以及MIS各个子系统同时共享调度实时数据的技术手段,并介绍了系统在电网信息管理系统中的具体应用。