橡胶扭转减振器性能的试验与仿真分析

为了分析减振器的装配性能与工作性能,以某型汽车发动机的一款橡胶扭转减振器为研究对象,应用ABAQUS软件建立有限元模型,对扭转减振器橡胶圈压装、滑移扭转和压脱过程进行仿真.比较压入力、滑移转矩与压脱力3个参数峰值的试验值与模拟值,验证仿真模型的可靠性.采用该仿真模型,对橡胶扭转减振器结构的再设计开展应用研究.结果表明:减振器型腔结构改进后的装配性能、工作性能都有明显的提升.     

阻尼多状态切换减振器的性能仿真与试验

传统的阻尼可调减振器,主要通过改变节流口面积实现阻尼可调,工作模式比较单一,阻尼可调范围有限.为了增加阻尼可调的工作模式和调节范围,以某被动式液压减振器为基础,设计出一种具有多状态特性的阻尼可切换减振器.为了分析该减振器的性能,结合流体力学及热力学理论,建立了阻尼多状态切换减振器系统的数学模型,运用Simulink仿真分析了减振器输出力与减震器行程、频率的关系,并与减震器的台架试验结果进行对比验证.结果表明:阻尼力试验值与仿真值的偏差较小,所建的减振器数学模型具有较高的精度,且减振器阻尼状态变化明显,阻尼切换控制准确,为汽车半主动悬架的控制提供了理论依据.     

阻尼多状态切换减振器的性能仿真与试验

传统的阻尼可调减振器,主要通过改变节流口面积实现阻尼可调,工作模式比较单一,阻尼可调范围有限.为了增加阻尼可调的工作模式和调节范围,以某被动式液压减振器为基础,设计出一种具有多状态特性的阻尼可切换减振器.为了分析该减振器的性能,结合流体力学及热力学理论,建立了阻尼多状态切换减振器系统的数学模型,运用Simulink仿真分析了减振器输出力与减震器行程、频率的关系,并与减震器的台架试验结果进行对比验证.结果表明:阻尼力试验值与仿真值的偏差较小,所建的减振器数学模型具有较高的精度,且减振器阻尼状态变化明显,阻尼切换控制准确,为汽车半主动悬架的控制提供了理论依据.     

电磁阀连续可变阻尼减振器的建模与仿真

针对电磁阀型连续可变阻尼减振器的结构特点,分析该减振器的工作原理与阀系特征。以液压理论为基础建立该减振器的数学模型。利用MATLAB软件进行仿真分析,分别得到不同电磁可变节流孔面积时该减振器仿真与试验的速度特性图与示功特性图。仿真数据与试验所得数据相比较,验证模型的正确性。通过对该减振器关键参数仿真分析,得到电磁阀的可变节流孔的面积、复原阀的弹簧预紧力、复原阀的固定节流孔宽度以及复原阀的阀片当量厚度等参数对该减振器阻尼力的影响。为电磁阀型连续可变阻尼减振器的研究提供了一定的参考依据。     

基于阻尼状态切换的装载机座椅悬架控制

为提高装载机驾驶员作业舒适性,提出了一种基于阻尼多状态切换减振器的装载机半主动座椅悬架系统.分析了阻尼多状态切换减振器的设计原理及油液流动行为,建立了阻尼多状态切换减振器数学模型,通过仿真分析获取了减振器4种阻尼状态下的复原阻尼系数和压缩阻尼系数,在此基础上,进一步构建了装载机半主动座椅悬架系统混杂动力学模型,设计了用于座椅半主动悬架的权值系数模糊自适应调整混杂模型预测控制策略,并在随机路面激励输入下进行了控制策略性能仿真分析.仿真结果表明:所提出的装载机半主动座椅悬架及其控制策略能够有效降低座椅垂向振动加速度均方根值,降幅达35.71%,同时改善座椅悬架动行程达30.88%,驾驶员作业舒适性得到显著提升.     

金属橡胶非线性减振系统混沌特性研究

对金属橡胶非线性减振系统的混沌特性进行了研究,建立了系统的力学模型,对减振器进行了静、动态试验,识别了减振器的各参数,通过求解系统响应随激励参数变化的分岔图,确定了系统产生混沌时激励力和频率的取值,采用Runge-Kutta法求解并绘制了系统的位移时间历程图、相图、Poincaré映射图和频谱图,计算了Lyapunov指数最大值,并在Adams软件环境下进行了仿真试验验证,证明了金属橡胶非线性减振系统具有混沌振动特性.      

双筒液压减振器异响的计算机仿真研究

利用基于Bouc-wen滞回环的非线性减振器模型对减振器进行计算机仿真分析,发现减振器可变阻尼力的减小是减振器异响产生的原因,同时给出了避免可变阻尼力减小的方法.     

车用双筒液压减振器的热力学模型与试验研究

分析了减振器生热机理以及热量传递途径,在此基础上利用能量守恒定律以及热力学第一定律建立减振器热力学模型,通过求解模型获得减振器在工作过程中温度随时间的变化情况.将仿真结果与试验结果进行比较,分析误差产生的原因,结果表明减振器在工作过程中温度的变化主要是由于减振器不同腔室内油液与减振器筒之间的热量交换以及减振器外筒与周围空气之间的热量交换引起的.     

织机系统的减振设计与动态仿真

研究织机系统的减振设计问题.建立了织机系统的动力学模型,对减振器的参数进行了初步设计和动态优化设计.应用计算机动态仿真技术,仿真织机加装减振器后的振动响应.获得了具有最佳减振效果的减振器结构参数为铅垂:铅垂向刚度25.1×104N/m,铅垂向阻尼6273N.s/m.振动响应测试表明,减振器的动态响应及隔振效率均达到设计要求.     

汽车悬架液压减振器热机耦合动力学模型

针对汽车悬架液压减振器建立了由路面不平度激励模型、非线性悬架振动模型、考虑温度影响的减振器阻尼力试验数据模型、减振器热动力学模型子模型组成的耦合动力学效应的理论分析模型.通过减振器阻尼力特性试验数据建立了考虑温度影响的非线性阻尼力试验模型,利用减振器发热特性试验数据辨识了减振器热动力学模型参数.利用所建立的耦合动力学理论模型预测了减振器温度上升动态过程,并进行了影响因素的仿真分析.研究表明,减振器的热机耦合效应在高速行驶和较差路面条件下表现突出,而在低速或者良好路面条件下不明显;行驶车速、路面等级、环境温度与减振器周围空气流动速度、悬架非簧载质量、减振器壳体换热面积对减振器发热平衡温度高低具有很大影响,而悬架等效刚度、簧载质量和减振器壳体比热容参数对之影响很小.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

正~~     

An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.