钢筋混凝土异形柱框架结构层间位移角限值研究

对钢筋混凝土异形柱框架结构抗震性能的研究尚未形成一致的结论。通过对现有研究成果的比较可以发现,这类结构的变形能力介于钢筋混凝土矩形柱结构和剪力墙结构之间,其弹性层间位移角限值应以控制填充墙的墙面裂缝贯通为判断标准,弹塑性层间位移角的取值应当既有一定的保证率,又要符合工程实际,建议取1/75比较合适。     

热带气旋迁移加速度的统计规律

热带气旋运动规律的研究对于揭示热带气旋运动的机理、进而提高热带气旋预报的精度具有重要意义。本文对联合台风预警中心和美国国家飓风中心发布的1979—2016年间全球4907个热带气旋事件的观测数据进行统计分析,得到了全球范围内热带气旋中心迁移加速度的若干规律。研究表明,纬度变化对于热带气旋的迁移具有重要的影响,热带气旋迁移加速度沿纬线方向分量的平均值在低纬度地区接近于0,随着纬度增大,呈现出向东加速且加速度有不断增加的趋势。南北半球的规律具有明显的相似性。不同区域内平均经线方向加速度随纬度变化的规律不如纬向加速度明显,随着纬度的增加,差异增大。     

基于弱可观状态分离估计的机载灵巧弹药快速传递对准方法

为了解决机载灵巧弹药微机电系统(MEMS)惯性导航传递对准时间过长、严重制约载机安全的问题,提出了MEMS陀螺零偏两点估计算法和弱可观测状态分离估计的快速传递对准算法。该方法基于对Kain等^［1］提出的速度+姿态匹配快速传递算法的可观测度分析,解决了陀螺零偏弱可观测状态的分离估计。采用系统噪声变分贝叶斯-卡尔曼滤波自适应算法处理快速传递对准算法中分离估计器参数对滤波器收敛的影响。仿真和靶场试验结果表明,在2.5 s内两点估计法估计准确度至少达到88%,对应的传递对准时间缩短到8 s.     

车载捷联惯导系统陀螺漂移在线自标定方法研究

为提高车载捷联惯导系统标定效率,提出了一种基于卡尔曼滤波的陀螺漂移在线自标定方法,该方法利用北向陀螺漂移的完全可观测性,在近似水平条件下,通过卡尔曼滤波估计出两个不同位置的等效北向陀螺漂移,然后利用该估计值和解算出的方位角计算出陀螺漂移实际值,实现陀螺漂移的在线自标定。仿真结果表明,该方法简单可行,标定精度能够满足车辆导航要求。     

海洋潜标新型电源系统研制

介绍了一种应用在海洋环境监测潜标上的新型电源系统。该系统主要由异形聚合物锂离子电池与保护电路(PCM)组成。简述了该系统的结构与功能。配备该系统的潜标完成了3次为期8个月的海洋应用试验。试验结果表明:该系统运行可靠与安全,可循环充电使用,全寿命费用较低。     

层数和层高对高层建筑剪力墙数量的影响

运用有限元结构软件SATWE通过对工程实例计算分析,研究高层建筑剪力墙结构的层数和层高变化对剪力墙数量的影响,得出一些参考建议。一般在高层建筑剪力墙结构的设计时尽量使得建筑物的高宽比不大于4,能控制建筑物的造价成本;改变结构的层高要比改变结构的层数对剪力墙结构的刚度影响更加显著;结构层数和结构层高增加时,通过增加剪力墙墙厚保证结构的最大层间位移角不变的条件下,会对结构的整体稳定和安全造成不利的影响。     

隔震设计在某民用建筑中的应用

本文介绍了利用midas gen对某隔震结构进行结构分析。利用midas gen非线性有限元时程分析方法,通过计算对设置隔震支座前后结构的有关参数进行对比分析,如自振周期、层间剪力、顶点绝对加速度,分析结果表明,采用隔震支座后可以显著降低上部结构的地震作用。     

Seismic performance of torsionally stiff and flexible multi‐story concentrically steel braced buildings

It is expected that application of torsion provisions in typical seismic codes shows different levels of efficiency for torsionally stiff and flexible buildings. This paper studies difference in performances of a range of code designed torsionally stiff and flexible five‐story building models. The models are classified in eight configurations to cover common range of buildings designed with the seismic provisions of Iranian Standard 2800 as a typical seismic design code. Seismic nonlinear dynamic time history behavior of eight building models subjected to seven horizontal bi‐directional design spectra compatible ground motions is investigated. These models cover a wide band of very torsionally stiff to very flexible buildings. Response parameters are element ductility demand and building story drift ratio. These criteria are appropriate indices for structural and nonstructural damages, respectively. The results indicate that the present linear static procedure of building codes such as the Iranian Standard 2800 is not generally adequate for structures with very low torsional stiffness. Copyright © 2012 John Wiley & Sons, Ltd.     

Evaluation of deflection amplification factor in steel moment‐resisting frames

Steel moment‐resisting frames (SMRFs) are the most common type of structural systems used in steel structures. The first step of structural design for SMRFs starts with the selection of the structural sections on the basis of story drift limitation. ASCE 7 (2010) requires that the inelastic story drifts be obtained by multiplying the deflections determined by elastic analysis under design earthquake forces with a deflection amplification factor (C_d). For special moment‐resisting frames, C_d is given as 5.5 in ASCE 7 (2010). Lower C_d values will increase the overall inelastic response of the structure. On the other hand, the inelastic response of the structure is expected to be less severe when designed for higher C_d values. The performance objective is that the structure should sustain the inelastic deformation demand imposed due to design earthquake ground motions. This study aims at investigating the inelastic seismic response that low‐rise, medium‐rise and high‐rise SMRFs can experience under design earthquake ground motions and maximum considered earthquake (MCE) level ground motions and evaluating the deflection amplification factors (C_d) for SMRFs in a rational way. For this purpose, nonlinear dynamic time history and pushover analyses will be carried out on SMRFs with 4, 9 and 20 stories. The results indicate that the current practice for computing the inelastic story drifts for SMRFs is rational and the frames designed complying with the current code requirements can sustain the inelastic deformations imposed during design earthquake ground motions when seismically designed and detailed. Copyright © 2013 John Wiley & Sons, Ltd.     

局部肘节消能装置的减振机制分析及其优化控制

传统的肘节式位移放大机构可以增大阻尼器变形从而提高结构减振效率,但其需占据较大空间,且相关的基于小变形假设的位移放大系数理论公式不能反映放大系数时变特性,难以实现几何构造优化。为此,提出一种以黏滞阻尼器为阻尼元件的局部肘节消能装置,其具有占用空间小、布置灵活等特点。基于几何关系推导局部位移放大系数解析解,并对其进行参数分析。分析结果表明：局部凸肘节消能装置的位移放大能力随下连杆与水平面夹角增大而增强,而局部凹肘节消能装置则与之相反;局部凸肘节消能装置的最优下连杆长度与装置高度之比位于［0.7,1.3］区间内,局部凹肘节消能装置的该比值约为0.7。根据改进D值法提出适用于框架结构的局部肘节消能装置层间位移放大系数计算方法。以消能装置在外部激励下最大侧移为基础,给出了针对层间位移放大系数的优化步骤,并通过算例分析验证局部肘节消能装置的可行性和几何优化方法的有效性。采用所提优化方法进行局部肘节消能装置设计,可有效增强其位移放大能力和振动控制效果。