Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load

The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA. The multi-material Eulerian and Lagrangian coupling algorithm was adopted. A flu-id-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground, multiple ALE element for simulating air and TNT explosive material. Numerical simulations of the blast pressure wave propagation, struc-tural dynamic responses and deformation, and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed. The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure. The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation. The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic defor-mation subjected to intensive blast waves, and columns lost carrying capacity, subsequently lead-ing to the collapse of the whole structure. The approach coupling influence between struc-tural deformation and fluid load well simulated the progressive collapse process of structures, and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load.     

当代网络文化中流行的表人新名词及其理据

当代网络文化之繁荣,孕育出形形色色的网络新名词。作为对日趋细化和多元人群的客观称谓和个性描述,表人的流行新名词在音形义等方面独具特色,或直接借用外来词,或灵活创造新词语,或赋予旧词以新义。表人的流行新名词既根植于社会生活,又深深地烙上了时代的印记,更忠实地映射出当今社会人们多姿多彩的生活方式和多元化的价值取向,有着深刻的言内外因素和文化心理理据。表人的新名词在生成和传播过程中也必须经受“汰弱留强”和“适者生存”等自然生态法则的检验,除了遵循语言发展规律和满足交际的现实之需,还有待大众传媒等方方面面予以包容和理性引导。     

Optimal sizing of piezo-actuators for minimum-deflection design of frames under uncertain loads

Optimal piezo-actuator sizes and locations for a frame structure under bending load uncertainty are determined with the objective of minimizing the deflection under worst case of loading. The bending moments generated by the piezo-actuators are used for deflection control, i.e., to minimize the maximum deflection. The frame is subjected to a tip load which lies in an uncertainty domain with regard to its magnitude and direction. The specific uncertain loading studied in the present paper involves a load of given magnitude but of unknown direction, which should be determined to produce the highest deflection. The worst case of loading depends on the size and location of the actuators leading to a nested problem of optimization (design) and anti-optimization (uncertainty problem). Results are given for deterministic and uncertain loading conditions.     

略论和谐社会下政府管制构建之新思路

我国传统的政府管制具有很多弊端,已经对经济发展产生了相当的阻力.文章在\"构建社会主义和谐社会\"这一理论背景下,通过总结和谐社会的价值目标群,提出了以此为出发点和参照系的新型政府管制的构建思路和总目标,并对中观和微观层面的具体构建进行了尝试性探讨,以希为我国政府管制的成熟完善、真正发挥作用并最终促进人、经济与社会的全面发展有所裨益.     

专四英语议论文写作和语篇教学

语言与思维密切相关,英汉民族各不相同的两种思维模式决定了英汉议论文的篇章结构有各自的特点。写作的目的是表达思想、实现交际。为了保证交际的顺畅进行,英语议论文理所当然应该用英语民族人的思维方式来组织结构,尽量避免汉语文章结构的负迁移。因此,在日常的英语专业写作教学中,教师很有必要努力探索语篇教学的方法并大力开展语篇教学。     

Static analysis of synchronism deployable antenna

INTRODUCTION Large antennas for space applications have some differences as compared to their counterparts de-signed and manufactured for ground usage. For a larger space antenna, the applied loads in space can be several orders of magnitude less than the gravity loading it is subjected to when being fabricated and assembled on the ground. Since the effect of gravity cannot be removed from any experimental verifica-tion performed on the ground, we must rely on the use of efficient and hig…     

智慧在“同课异构”参研活动中提升——以《孔乙己》教研活动为例

参加每次教研活动,我们的教学智慧都会得到一些提升.一次《孔乙己》“同课异构”教研活动的参研,使我深深地体会到:课前的明确分工,课堂教学的准确定位,关注课堂教学的语文味是课堂有效教学的制胜法宝.当然,精彩的课堂总是携带着一种缺憾.     

当代中国体育人口结构的社会学分析

以2001年全国群众体育调查数据库为资源,在当代社会背景下对我国体育人口结构进行分析。研究发现,体育人口的每一结构由于受诸多社会因素影响,呈现出明显的时代特征：性别结构男性高于女性;地域结构城市高于农村、东部高于西部;年龄结构呈现两端高中间低的“马鞍型”等等。经过研究指出,欲求改善体育人口结构以度群众体育的快速发展,应以当代中国社会背景为参照系,对影响体育的社会问题进行分析,并指出国家政策对社会问题的解决是体育人口结构改善的突破口。     

学习环境的社会结构设计

学习科学在学习的社会维度上的强调,要求学习环境的设计超越传统技术中心的设计视界,更加关注学习的社会结构设计。文章概要描述了一个由“文化信念”、“实践”、“社会-技术-空间关系”、“与外部世界的交互”四维度组成的社会结构设计框架,并借此分析了一个智能互动白板技术环境下的课堂社会结构的设计研究案例。研究表明,学习的社会结构是影响整个学习环境设计效果的重要因素,应该引起广大教育技术研究者们的重视与关注。     

“建筑结构”课程的教学内容及教学思考

本文以建筑工程管理专业和工程造价专业所开设的“建筑结构”课程为研究对象,对其教学内容及教学方法均做了一定的思考。对教学内容的整合优化有利于在有限的课时内完成重点难点内容的教学。对教学方法除理论教学外,提出了实践教学方法,实践中着重要求学生掌握“11G101-1混凝土结构施工图平面整体表示方法制图规则和构造详图”图集相关知识,这有利于学生今后尽快适应工作岗位的需求。总之,不管是教学内容改革还是教学方法改革,最终的目标均为提高教学质量且培养社会需求的人才。