Seismic performance analysis and design suggestion for frame buildings with cast-in-place staircases

Many staircases in reinforced concrete （RC） frame structures suffered severe damage during the Wenchuan earthquake. Elastic analyses for 18 RC structure models with and without staircases are conducted and compared to study the influence of the staircase on the stiffness, displacements and internal forces of the structures. To capture the yielding development and damage mechanism of frame structures, elasto-plastic analysis is carried out for one of the 18 models. Based on the features observed in the analyses, a new type of staircase design i.e., isolating them from the master structure to eliminate the effect of K-type struts, is proposed and discussed. It is concluded that the proposed method of staircase isolation is effective and feasible for engineering design, and does not significantly increase the construction cost.

A new methodology for energy-based seismic design of steel moment frames

A procedure is proposed whereby input and hysteretic energy spectra developed for single-degree-of-freedom （SDOF） systems are applied to multi-degree-of-freedom （MDOF） steel moment resisting frames. The proposed procedure is verified using four frames, viz., frame with three-, five-, seven- and nine-stories, each of which is subjected to the fault- normal and fault-parallel components of three actual earthquakes. A very good estimate for the three- and five-story frames, and a reasonably acceptable estimate for the seven-, and nine-story frames, have been obtained. A method for distributing the hysteretic energy over the frame height is also proposed. This distribution scheme allows for the determination of the energy demand component of a proposed energy-based seismic design （EBSD） procedure for each story. To address the capacity component of EBSD, a story-wise optimization design procedure is developed by utilizing the energy dissipating capacity from plastic hinge formation/rotation for these moment frames. The proposed EBSD procedure is demonstrated in the design of a three-story one-bay steel moment frame.

Improving the design of reinforcing frames by simulating the arch and peltate venation structures

Based on the analyses on arch and peltate venation structures, the design of reinforcing frames was improved. First, distribution rules of the arch structure were summarized. According to the load condition and the structure of the frame, a mechanical model of arch structure was devel- oped, and two solutions for the model were analyzed and compared with each other. Through the a- nalysis, application rules of arch structure for improving the design were obtained. Then, distribu- tion rules of peltate venation structure were summarized. By using the same method, application rules of peltate venation structure for improving the design were also obtained. Finally, mechanical problem of the frame was described, and rib arrangement of the frame was redesigned. A parameter optimization for the widths of ribs in bionic arrangement was also carried out to accomplish the im- proving design. Comparison between bionic and conventional reinforcing frames shows that the weight is reduced by as much as 15.3%.

A Framework for Web-Based Mechanical Design and Analysis

In this paper, a Web-based Mechanical Design and A na lysis Framework (WMDAF) is proposed. This WMADF allows designers to develop web -based computer aided programs in a systematic way during the collaborative mec hanical system design and analysis process. This system is based on an emerg ing web-based Content Management System (CMS) called eXtended Object Oriented P ortal System (XOOPS). Due to the Open Source Status of the XOOPS CMS, programs d eveloped with this framework can be further customized to satisfy the demands of the user. To introduce the use of this framework, this paper exams three differ ent types of mechanical design and analysis problems. First, a repetitive design consideration and calculation process is transferred into WMADF programs to gai n efficiency for wired collaborative team. Second, the considered product solid model is created directly through the use of XOOPS program and Microsoft Compone nt Object Model (COM) instances. To the end of the paper, an example linked with ANSYS is used to indicate the possible application of this framework.

Peak displacement patterns for the performance-based seismic design of steel eccentrically braced frames

Performance-based seismic design(PBSD) aims to assess structures at different damage states. Since damage can be directly associated to displacements, seismic design with consideration of displacement seems to be logical. In this study, simple formulae to estimate the peak floor displacement patterns of eccentrically braced frames(EBFs) at different performance levels subjected to earthquake ground motions are proposed. These formulae are applicable in a PBSD and especially in direct displacement-based design(DDBD). Parametric study is conducted on a group of 30 EBFs under a set of 15 far field and near field accelerograms which they scaled to different amplitudes to adapt various performance levels. The results of thousands of nonlinear dynamic analyses of EBFs have been post-processed by nonlinear regression analysis in order to recognize the major parameters that influence the peak displacement pattern of these frames. Results show that suggested displacement patterns have relatively good agreement with those acquired by an exact nonlinear dynamic analysis.

Hydroforming Process Design Using Finite Element Simulation for a Vehicle Instrument Panel Support Frame

Tubular hydroforming has attracted increased attention in the vehicle industry recently. This paper covers a complete hydroforming process design for an instrum ent panel frame by finite element simulation using the explicit code LS-DYNA. The manufacturing process for the instrument panel frame consists of tube pre-be nding and final hydroforming. To accomplish hydroforming process design successf ully, a thorough investigation of proper combination of process parameters such as internal hydraulic pressure and axial feeding is carried out by finite element simulation to predict the tube wall thickness and shape. An optimized process parameter combination is obtained and verified by the instrument panel frame hyd roforming experiment. The experiment shows that designed process parameters can be used in real production through FEA simulation, but tubular thinned amplitu de by FEA is less than that with the experiment.

A Computer-aided Design System for Framed-mould in Autoclave Processing

The general computer-aided design （CAD） software cannot meet the mould design requirement of the autoclave process for composites, because many parameters such as temperature and pressure should be considered in the mould design process, in addition to the material and geometry of the part. A framed-mould computer-aided design system （FMCAD） used in the autoclave moulding process is proposed in this paper. A function model of the software is presented, in which influence factors such as part structure, mould structure, and process parameters are considered; a design model of the software is established using object oriented （O-O） technology to integrate the stiffness calculation, temperature field calculation, and deformation field calculation of mould in the design, and in the design model, a hybrid model of mould based on calculation feature and form feature is presented to support those calculations. A prototype system is developed, in which a mould design process wizard is built to integrate the input information, calculation, analysis, data storage, display, and design results of mould design. Finally, three design examples are used to verify the prototype.

Effect of URM infills on seismic vulnerability of Indian code designed RC frame buildings

Unreinforced Masonry (URM) is the most common partitioning material in framed buildings in India and many other countries. Although it is well-known that under lateral loading the behavior and modes of failure of the frame buildings change significantly due to infill-frame interaction, the general design practice is to treat infills as nonstructural elements and their stiffness, strength and interaction with the frame is often ignored, primarily because of difficulties in simulation and lack of modeling guidelines in design codes. The Indian Standard, like many other national codes, does not provide explicit insight into the anticipated performance and associated vulnerability of infilled frames. This paper presents an analytical study on the seismic performance and fragility analysis of Indian code-designed RC frame buildings with and without URM infills. Infills are modeled as diagonal struts as per ASCE 41 guidelines and various modes of failure are considered. HAZUS methodology along with nonlinear static analysis is used to compare the seismic vulnerability of bare and infilled frames. The comparative study suggests that URM infills result in a significant increase in the seismic vulnerability of RC frames and their effect needs to be properly incorporated in design codes.

基于BIM技术与模拟退火算法的村镇轻钢框架结构智能设计方法

传统村镇住宅结构设计需要进行大量的人工试算与重复建模,而受制于建设成本,村镇住宅无法像城镇住宅一样通过设计师进行专业的结构设计与验算,其安全性与经济性均难以满足要求。为此,提出一种村镇轻钢框架结构智能设计方法,包括智能建模与智能优化两个环节。基于图层自动识别算法、光学字符识别技术、自适应分块算法提出村镇轻钢框架结构BIM智能建模方法,包括图层识别、轴文本数据提取、墙体轮廓提取等,智能建模结果基本满足实际工程要求。基于提出的两阶段模拟退火算法给出村镇轻钢框架结构的智能优化方法,优化速度较快,优化效果良好。通过实际工程案例对提出的智能设计方法进行验证,结果表明,提出的村镇轻钢框架结构智能设计方法具有可行性,与传统的人工设计方法相比,设计周期可缩短70%以上,材料用量、结构设计指标接近人工设计结果。

Seismic design factors for RC special moment resisting frames in Dubai,UAE

This study investigates the seismic design factors for three reinforced concrete （RC） framed buildings with 4, 16 and 32-stories in Dubai, UAE utilizing nonlinear analysis. The buildings are designed according to the response spectrum procedure defined in the 2009 International Building Code （IBC＇09）. Two ensembles of ground motion records with 10% and 2% probability of exceedance in 50 years （10/50 and 2/50, respectively） are used. The nonlinear dynamic resPonses to the earthquake records are computed using IDARC-2D. Key seismic design parameters are evaluated; namely, response modification factor （R）, deflection amplification factor （Cd）, system overstrength factor （Ωo）, and response modification factor for ductility （Rd） in addition to inelastic interstory drift. The evaluated seismic design factors are found to significantly depend on the considered ground motion （10/50 versus 2/50）. Consequently, resolution to the controversy of Dubai seismicity is urged. The seismic design factors for the 2/50 records show an increase over their counterparts for the 10/50 records in the range of 200%-400%, except for the D~ factor, which shows a mere 30% increase. Based on the observed trends, perioddependent R and Cd factors are recommended if consistent collapse probability （or collapse prevention performance） in moment frames with varying heights is to be expected.

绘本图画叙事中的情节展示艺术探析

以叙事学理论为指导研究绘本的图画叙事、版式设计和画框调节是实现绘本图画叙事的重要手段。利用版式设计和画框变化页面中的图画形态及其关系,使绘本中的系列图画在读者的视知觉及想象中形成连贯性、叙事性,以及叙事节奏的起伏变化。

双目标优化与生成对抗网络结合的框架结构阻尼器布置方案智能设计方法

为实现框架结构的阻尼器智能化布置,结合减震设计原理和智能算法,采用双目标优化算法和生成对抗网络算法分别进行阻尼器竖向和水平智能布置研究,并将该方法应用到两个框架结构减震设计工程案例中。在框架结构减震设计中,采用双目标优化算法进行阻尼器竖向布置,并与逐层逼近法、工程师设计和非减震设计进行对比,结果表明,采用该优化算法得到的阻尼器竖向布置方案能有效降低层间位移角和楼层加速度,提高结构的抗震性能。在确定各楼层的阻尼器数量后,利用训练好的生成对抗网络生成模型,可快速、自动地选择和确定各楼层阻尼器的平面安装位置,生成的平面布置与工程师设计的平面布置在相似性差异度综合评价指标上小于临界值0.1,说明两者相似度较高,且有利于提高原结构的抗扭能力。将双目标优化算法与生成对抗网络相结合,不仅能满足框架结构的减震性能目标,而且可实现阻尼器布置方案的智能设计,提升减震工程设计效率。

日本中世唐样佛堂的间架谱系及其与宋技术的关联性

日本唐样建筑以宋元江南建筑为祖型,是以往学界一致认定的通说。然分析发现,唐样建筑技术成分并不单一,间架形制上存在中国北系因素。本文基于东亚技术关联性的视角,比较与分析日本中世唐样佛堂的间架谱系及其技术源流,指出中世唐样建筑是探讨东亚设计技术演变的重要标本和线索。

框架式人造板装卸机的设计与有限元分析

人造板装卸机是板式家具生产线中的原料板材装卸机构,其使用可使人造板生产线的布局更为合理,缩短生产进料时间,提高原料板材装卸过程的自动化水平,提升企业的生产效率。采用Solidworks对框架式人造板装卸机机架进行了立体结构建模,利用Ansys-Workbench对其受力及强度进行仿真分析与验证。

平衡车车架拓扑优化设计与仿真分析

目的本研究以平衡车车架为研究对象,旨在满足模型强度与刚度约束条件的前提下,通过拓扑优化设计实现车架质量的减轻,从而为平衡车车架的轻量化设计提供参考。方法首先,通过SolidWorks软件建立车架的三维模型,然后利用ANSYS Workbench对原始车架进行静力学分析,以获取车架的应力分布情况。在此基础上,采用AltairInspire软件对原模型进行拓扑优化,优化目标是减少车架的质量。结果经过拓扑优化设计,得到了优化后的重构模型。与原始车架相比,优化后的车架质量减少了约54.0%。虽然优化后的车架在满足使用规范的前提下,米塞斯应力有所上升,但仍小于材料的屈服强度,确保了车架的安全性和稳定性。结论本研究通过拓扑优化方法有效地减少了平衡车车架的质量,同时保持了必要的结构强度和刚度。尽管优化后车架的应力有所增加,但仍在材料允许范围内,证明了拓扑优化在车架轻量化设计中的可行性。该方法为未来平衡车车架部件的设计和改进提供了新的思路和参考。

减隔震技术对9度近断层区框架结构抗震性能影响与经济性分析

为研究减隔震技术对9度近断层区框架结构抗震性能影响及其经济性,以某多层框架结构为研究对象,在保证结构力学指标为85%的规范限值的原则下,对其分别进行抗震、减震、隔震设计,采用ETABS软件建立结构的抗震、减震、隔震模型并对其进行近断层和非近断层地震动作用下的抗震性能对比分析,以及工程量和经济性分析。结果表明,各模型在近断层地震动下的反应大于非近断层地震动下的。在近断层罕遇地震下,相较于抗震模型,隔震模型最大层间位移角减小6898%,楼面峰值加速度减小7677%,楼层剪力减小8367%;相较于抗震、减震模型,隔震模型在近断层多遇地震和设防地震下的响应及填充墙破坏程度最小,隔震结构抗震性能最优。相较于抗震模型,减震、隔震模型造价分别降低857%、554%,所以减震设计的工程造价最低。

四川大学博物馆结构设计重难点分析研究

四川大学博物馆采用钢框架结构体系,并设置屈曲约束支撑改善结构的抗震性能。介绍了四川大学博物馆的结构设计参数及抗震性能目标。针对结构设计中的重难点,开展了屈曲约束支撑的工作机理分析、框架柱计算长度与穿层柱分析、东侧大悬挑空间的相关分析。利用反应谱分析及时程分析探究了屈曲约束支撑工作机理,分析结果表明,屈曲约束支撑能够有效改善钢结构产生塑性铰的状况,起到保护主体钢框架的作用。针对东侧大悬挑空间的功能要求,设计采用了屋顶桁架结合钢拉杆吊挂东侧大楼梯的结构形式,通过结构防连续倒塌分析、楼板应力分析、楼盖舒适度分析、关键节点有限元分析等确保该部位结构设计安全合理。对整体结构受力机理和薄弱部位进行了研究,提出了重点部位的设计原则和加强措施。

单座小型赛车车架设计与仿真

单座小型赛车广泛用于各游乐场所、汽车竞赛以及赛道日活动,由于产量低、用途单一且不能合法上路,故无需遵守量产车的设计原则和相关法规,设计空间较大。这种赛车通常注重加速/制动性能以及操控稳定性,其中中国大学生方程式汽车大赛(FSC)是单座小型赛车的代表产品。车架是单座小型赛车的重要组成部分,绝大多数的赛车零部件都需要安装在车架上。本文以中国大学生方程式赛车规格的单座小型赛车车架为研究对象,设计一副具有足够刚度和强度的车架并进行优化,基于UGNX和ANSYS Workbench软件平台,分别建立车架三维模型和有限元模型,计算车架弯曲刚度和扭转刚度并完成模态验证。

面向均匀损伤的RC框架结构抗震优化设计方法

RC框架结构在地震作用下多出现局部楼层损伤明显或抗力不足问题,通过对抗侧力构件性能的合理优化可实现各楼层损伤程度相近的设计效果,消除薄弱层,达到更为理想的均匀损伤分布模式。提出RC框架结构的均匀损伤设计方法,以各楼层损伤指数相等或相近为优化目标,各层框架柱配筋率为优化变量,通过智能算法与有限元平台协同计算技术,实现RC框架结构均匀损伤优化设计,并采用弹塑性时程分析和IDA方法对优化效果进行验证分析。结果表明,通过智能算法优化框架柱配筋方案可以有效调控结构各层损伤程度,不同地震波作用下结构最优配筋率分布是不完全相同的,并且框架柱的最优配筋率分布也未呈现明显的统计规律,但将不同地震波下优化结果的均值作为框架柱配筋方案可以提高结构抗震能力,该优化方法合理有效。

高烈度区多层长悬挑钢结构设计

长安乐传媒港是十四届全运会重要配套项目,为南侧带3层大悬挑的不规则复杂结构,最大悬挑长度38.5m。主体结构采用钢结构框架-支撑体系,悬挑部分采用钢桁架结构。针对大悬挑结构设计难点开展了分析和研究;重点介绍了整体结构方案选型、结构整体分析结果以及结构抗震性能化设计结果;也重点介绍了单人行走激励和人群激励下悬挑钢桁架舒适度分析,考虑长悬挑结构安装过程、卸载顺序和楼板刚度形成次序的施工模拟分析,以及长悬挑对基础设计的影响。结果表明,本工程的多层长悬挑构结构具有较高的安全储备,整体结构具有良好抗震性能;长悬挑结构设计中需要特别关注施工过程的影响,基础设计时应考虑竖向构件受拉的不利影响。