具有时变不确定参数的线性时滞系统的鲁棒镇定

研究了具有时变不确定参数的线性时滞系统的鲁棒镇定问题．提出鲁棒稳定化控制器一种新的设计方法．现有的一些结果可以作为本文的一些特例得到．     

Optimal filtering over linear observations with unknown parameters

This paper presents the optimal filtering and parameter identification problem for linear stochastic systems over linear observations with unknown parameters, where the unknown parameters are considered Wiener processes. The original problem is reduced to the filtering problem for an extended state vector that incorporates parameters as additional states. The resulting filtering system is bilinear in state and linear in observations. The obtained optimal filter for the extended state vector also serves as the optimal identifier for the unknown parameters. Performance of the designed optimal state filter and parameter identifier is verified for both, positive and negative, parameter values.     

不同加载角T形钢管混凝土压弯承载力研究

采用有限元软件ABAQUS建立了不同加载角T形带肋和多室钢管混凝土压弯构件的计算模型,数值计算结果与试验结果吻合良好。对影响T形钢管混凝土柱水平荷载P-水平位移Δ关系曲线的参数进行分析,结果表明:加载角为0°时,T形钢管混凝土构件的承载力最低,在67.5°负向加载时,构件的承载力最大,比0°加载角构件大13%左右,加载角为45°~90°间承载力总体上差别不大。随着钢管屈服强度、混凝土抗压强度、钢管长厚比、带肋和多室T形钢管混凝土构件在斜向加载的承载力增加,在传统钢管混凝土基础上,提出了适用于不同加载角带肋和多室T形钢管混凝土压弯构件的承载力设计方法,简化计算公式与有限元结果、试验结果均吻合较好。     

大型油船货油装卸仿真模拟装置的开发

运用计算机仿真技术和V isual C 软件设计工具,开发研制基于大型油船货油装卸系统的仿真模拟装置,以供教学与船员培训之用.探讨大型油船货油装卸仿真模拟装置的应用,介绍系统的结构以及软件的实现方法.     

皮带煤仓转载工程施工体会

本文介绍了开滦钱家营矿业分公司八采区皮带煤仓转载工程的卸载硐室、煤仓、给煤机硐室的施工工艺,采用合理、先进的施工方案,实现了安全、优质、高效。     

复合地基载荷实验的数值分析

文章根据复合地基早加载、非极限加载的工程载荷实验情况,为进一步了解复合地基极限沉降变形性能,作者运用多种形式的数值分析方法,对载荷-沉降实验数据进行分析、预测、拟合,预测更大加载下的沉降值,并对各种模型的拟合以及预测结果分析进行分析,找出适合加载阶段、预测阶段模拟方程.为确定复合地基承载力提供参考.     

刚架在结点集中力作用下无弯矩情况的判定

分析了忽略杆件的轴向变形时,刚架在结点集中力作用下弯矩处处为零的3种情况.从而使刚架的内力计算得到简化.     

循环荷载作用下铝合金轴压构件稳定性能分析

研究了循环荷载作用下铝合金轴压构件的力学性能,并与钢轴压构件进行比较。采用通用有限元分析软件ANSYS对铝合金轴压构件的滞回性能进行有限元分析。分析方法考虑了材料非线性、几何非线性和初始缺陷的影响。根据计算结果,得到了6061-T6铝合金、6061-T4铝合金和Q235钢3种材料轴压构件的滞回曲线、恢复力骨架曲线和刚度退化曲线,并进行了比较研究。分析结果显示,铝合金轴压构件的滞回性能与低碳钢轴压构件较为类似,并受到材料本构关系的显著影响。     

Circles with a suspended aid: reducing pommel reaction forces

The aim of this study was to investigate the influence of a suspended aid on the reaction forces during a basic skill on pommel horse. Twenty gymnasts performed three sets of 10 circles with and without a suspended aid on a pommel horse under which two force plates were set. The results confirmed that the suspended aid could reduce the magnitude of the pommel reaction forces during circles while maintaining the general loading pattern. On the left hand, the average and peak forces were attenuated to 0.59 body weight (BW) and 0.85 BW from 0.76 BW and 1.13 BW, respectively. The right hand experienced slightly larger forces with no-aid trials, but the asymmetry between the hands decreased with the aid. Despite a relatively large variability, all gymnasts experienced smaller impact peak forces with the aid. A suspended aid is most commonly used for a beginner gymnast as an introduction to pommel horse exercises. However, this study confirmed that it can also be useful for all levels of gymnasts who would like to practice pommel horse exercises with reduced pommel reaction forces for a purpose such as a progression for learning a new skill, control of training volume, or rehabilitation.     

Numerical Modeling of Response and Damage of Masonry Walls to Blast Loading

To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results.