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1.
运用统计能量分析法进行轿车内噪声的仿真   总被引:6,自引:1,他引:5  
建立了一个统计能量分析(SEA)芭轿车内室噪声的仿真计算,结果表明400-5000Hz频率范围内的空气噪声和固体噪声都适用于统计能量分析方法,SEA模型的计算与车内声压水平实测值精度在主要频带达到3dB以内。  相似文献   

2.
基于SEA法的汽车道路噪声研究   总被引:1,自引:0,他引:1  
统计能量分析(SEA)法是一种有效的在高频域内减少振动噪声的分析方法.文中根据SEA法进行实车全模型分析,确定了降低车室内噪声水平的对策.运用SEA法分析汽车高频(400Hz以上)路面噪声,精度可控制在±3 dB以内.文中最后通过直接比较实车的试验结果和SEA分析结果,验证了这种方法的精确性.  相似文献   

3.
利用统计能量法软件VA One建立了轨道车辆SEA模型,理论计算了用于SEA分析的各种统计能量参数,最后对车辆内部噪声进行了预测.仿真结果表明:车内噪声主要集中在频率为500~1600 Hz范围内,不同状态下影响车厢内外噪声的主要噪声源会发生变化,噪声峰值出现的位置不同.  相似文献   

4.
出海管路系统的噪声振动及声辐射   总被引:6,自引:1,他引:6  
采用统计能量分析方法(SEA),通过一定的简化,建立了出海管路系统声传播和管口声辐射的简单SEA理论模型,分析了在平稳随机噪声激励下通海管路系统各组成结构的能量分布和管口声辐射功率,并研究和对比了不同管道几何参数情况下的管口辐射噪声,实验结果与其他数值分析方法所得结果较为吻合,SEA为各种声学参数的计算年代了一条较为可靠和高效的途径。  相似文献   

5.
利用有限元方法进行汽车室内噪声预测的研究   总被引:7,自引:2,他引:5  
探讨了进行汽车室内噪声预测的基本方法,包括发动机,车身数学模型,利用有限元分析软件建立几何模型以及基于此几何模型进行的仿真计算,并设计实验进行了模型校验。对某型轿车室内噪声的预测结果,较好地符合了实际情况。  相似文献   

6.
初步探索了利用有限元方法进行汽车室内噪声优化的基本方法。建立了发动机、发动机悬置、副车架悬置和车身数学模型,结合Santana2000型轿车,利用有限元分析软件建立几何模型并进行仿真优化计算以及校验优化结果,其结果较好地符合了实际情况。  相似文献   

7.
轿车车内低频噪声预测与控制   总被引:3,自引:0,他引:3  
针对某型开发中的轿车,首先建立了白车身有限元模型并进行自由模态分析,通过与模态试验结果的对比进行模型修正,在此基础上,建立了含门窗的整车模型和车身-声场耦合有限元模型,并使用虚拟样机技术提取对车身的激励载荷,然后在SYSNOISE软件中进行车内低频(20~200Hz)噪声预测,最后通过板件贡献分析找出对车内噪声主要峰值贡献较大的板件并进行结构改进,计算表明取得了良好的降噪效果。该文的研究内容为新车型开发中的降噪设计提供了可借鉴的方法。  相似文献   

8.
降低轿车车内后部噪声的研究   总被引:1,自引:0,他引:1  
介绍应用现代试验和分析技术对轿车车内后部低频噪声源进行识别,并通过识别结果对轿车的原设计进行了改进,使轿车车内噪声得到明显改善。  相似文献   

9.
差分放大器的噪声分析及低噪声运用考虑   总被引:4,自引:0,他引:4  
噪声控制在电子电路设计中是至关重要的.介绍了噪声机制,构建了差分放大器的噪声模型,分析了其噪声来源,计算出其等效输入噪声,证明了差分放大器的低噪声应用.  相似文献   

10.
宽频地震仪数据采集通道的噪声分析   总被引:1,自引:0,他引:1  
为了从噪声理论角度验证宽频地震仪数据采集通道低噪声设计的合理性,采用等效En-In噪声模型理论和噪声的计算方法,对数据采集通道的固有噪声进行了分析与计算。通过实验结果及理论分析证明了所设计的宽频地震仪等效输入噪声小于2μV,满足系统噪声设计要求。同时实验结果与理论计算趋于一致,证明了此理论方法适合地震仪数据采集通道的噪声分析,为地震仪数据采集通道的低噪声设计奠定了基础。  相似文献   

11.
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.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
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。  相似文献   

14.
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  相似文献   

15.
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  相似文献   

16.
17.
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.  相似文献   

18.
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).  相似文献   

19.
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.  相似文献   

20.
Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.  相似文献   

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