磁流变阻尼器的实验建模

磁流变阻尼器是一种应用前景广阔的半主动控制阻尼器。基于对磁流变阻尼器的实验,建立了描述磁流变阻尼器阻尼特性的Bingham塑性模型和非线性滞回模型。讨论了施加电压（磁场强度）、激振振幅及频率对两种模型的参数的影响。该文提出的非线性滞回模型具有精度高、参数识别过程简单和准确反映磁流变阻尼器滞回特性等优点。     

双盘悬臂柔性转子一挤压油膜阻尼器系统的突加不平衡和加速响应特性

建立了双盘悬臂柔性转子一同心型挤压油膜阻尼器(SFD)系统的运动微分方程(定常转速和定常加速)及突加不平衡响应方程,分析了系统参数对于突加不平衡响应的影响和加速通过双稳态响应区的突加不平衡及加速响应特性。研究结果表明系统参数的变化对突加不平衡响应的变化有较大的影响。对于加速通过双稳态响应区的突加不平衡响应, 突加不平衡发生在不同的转速比区,响应走的路径也不相同不同的盘上发生突加不平衡, 对于不同临界响应有影响;对应两个盘上不同的不平衡量,不同阶临界转速处的加速度响应特性不同;当悬臂盘距SFD轴承支承的相对长度较大时, 系统整体的加速度响应特性较好, 但突加不平衡后的瞬态振幅也较大。     

MR智能材料在结构振动控制中的应用

磁流变智能材料是一种可控流体,它能在强磁场作用下从牛顿流体变化为有较高屈服应力的粘中塑流体,这种变化为连续可逆与迅速,用其制成的阻尼器具有简单、体积小、能耗低、可连续调节等优点,是结构实施半主动控制的理想装置。本文简要介绍了磁流变智能材料磁流变效应的机现及影响因素,与电流变（ＥＲ）液作了简单比较,建立了ＭＲ可调阻尼器工作原理和力学模型,并介绍其用于工程结构风振与地震的半主动控制的实施原则及可用范围     

缠绕式提升设备的防蹾罐装置

介绍了一种利用油气阻尼原理的立井缠绕式提升设备防足敦罐装置。     

煤矿风门自动闭锁气动控制装置的设计与应用

针对西山煤电集团各煤矿井下采用的普通单门扇风门存在的缺点,提出了一种煤矿风门自动闭锁气动控制装置,该装置结构紧凑,安装简单,安全性高。     

Automatic magnetic resonance image segmentation by fuzzy intercluster hostility index based genetic algorithm: An application

Segmentation of magnetic resonance (MR) images plays an important role in the medical science or clinical research. In this article, an application of a genetic algorithm (GA) based segmentation algorithm is presented for automatic grouping of unlabeled pixels of the MR images into different homogeneous clusters. Before the segmentation, the information about the optimal number of segments as well as the underlying pixel distribution of an image is not required in this method. The centroid of different segments is demarcated as active/inactive centroid by the fuzzy intercluster hostility index. After that, the test images are segmented by the selected active centroids. The optimal number of segments and their respective centroids are determined by this method. A performance comparison is manifested between the fuzzy intercluster hostility index based GA method and the well-known automatic clustering using differential evolution (ACDE) algorithm and one genetic algorithm based non-automatic algorithm with the help of two real life MR images. The comparison depicted the superiority of the GA based automatic image segmentation method with the help of fuzzy intercluster hostility index over other two algorithms.     

基于颗粒阻尼的变频空调压缩机管路减振设计

为解决变频空调压缩机管路振动问题，利用有限元法对管路进行动力学分析，在测点位置进行35～72 Hz变频试验测试。建立管路颗粒阻尼的能耗模型，通过离散元法确定颗粒材质、粒径和填充率等最优设计参数，并搭建管路减振试验台。振动试验结果表明：采用颗粒材质为铁基合金、颗粒粒径为2 mm、阻尼器填充率为90%的设计参数，当进气管采用B型阻尼器和45°布置方式，3个测点位置的加速度最大减幅分别为36.57%，30.15%，45.79%，当排气管采用A型阻尼器和水平方式时，3个测点位置的加速度最大减幅分别为40.87%，62.04%，50.42%。最后将试验的加速度响应变化趋势与耗能模型分析结果进行对比，验证了管路颗粒阻尼耗能模型的可行性。     

WCDMA网络基于MR的业务感知优化评估方法研究

目前移动网络数据业务呈爆发式增长,用户单纯的语音业务变化为不同QOS级别的复杂数据业务组合,用户感知对数据业务质量更为敏感。传统的评估方式只能通过CQT、DT、信令分析来发现解决点、线上的问题,本文打破传统,通过MR提取用户上报网络质量信息,利用大数据分析工具,创立一种评估分析方法,解决传统的点、线评估不足,进一步将网络质量与客户感知结合起来。     

Structural identification of a prototype pre-stressable leaf-spring based adaptive tuned mass damper: Nonlinear characterization and classification

The current paper focuses on a prototype adaptive TMD. Its design concept is based on pre-stressable leaf-springs that are controlled by piezoceramic (PZT) stack actuators. Experiments performed on the prototype showed that it is continuously tunable in a broad frequency range. Moreover, they revealed that the device exhibits structural nonlinearities. The current paper focuses on the structural identification of the prototype and attempts for the first time to characterize and classify the observed nonlinearities. Several experiments at different PZT voltage levels are performed. The results indicate PZT voltage dependent nonlinear softening and hardening stiffness. Based upon these observations, static experiments and proper data-pooling techniques, an effective “global” model for the nonlinear stiffness is derived. The estimated nonlinear model is finally validated upon static experiments as well as more realistic operational cases, that are vibrations of the prototype under typical ground excitation.     

Re-centering variable friction device for vibration control of structures subjected to near-field earthquakes

This paper proposes a re-centering variable friction device (RVFD) for control of civil structures subjected to near-field earthquakes. The proposed hybrid device has two sub-components. The first sub-component of this hybrid device consists of shape memory alloy (SMA) wires that exhibit a unique hysteretic behavior and full recovery following post-transformation deformations. The second sub-component of the hybrid device consists of variable friction damper (VFD) that can be intelligently controlled for adaptive semi-active behavior via modulation of its voltage level. In general, installed SMA devices have the ability to re-center structures at the end of the motion and VFDs can increase the energy dissipation capacity of structures. The full realization of these devices into a singular, hybrid form which complements the performance of each device is investigated in this study. A neuro-fuzzy model is used to capture rate- and temperature-dependent nonlinear behavior of the SMA components of the hybrid device. An optimal fuzzy logic controller (FLC) is developed to modulate voltage level of VFDs for favorable performance in a RVFD hybrid application. To obtain optimal controllers for concurrent mitigation of displacement and acceleration responses, tuning of governing fuzzy rules is conducted by a multi-objective heuristic optimization. Then, numerical simulation of a multi-story building is conducted to evaluate the performance of the hybrid device. Results show that a re-centering variable friction device modulated with a fuzzy logic control strategy can effectively reduce structural deformations without increasing acceleration response during near-field earthquakes.