Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences最新文献_第8页

A time–scale of formation of the first solids 第一个固体形成的时间尺度

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-10-15 DOI: 10.1098/rsta.2001.0895

J. Gilmour, J. Saxton

引用次数: 32

Injection of newly synthesized elements into the protosolar cloud 将新合成的元素注入原太阳云中

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-10-15 DOI: 10.1098/rsta.2001.0892

A. Boss, H. Vanhala

引用次数: 12

A new method for compensating actuator delay in real–time hybrid experiments 实时混合实验中作动器延迟补偿的新方法

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0878

Toshihiko Horiuchi, T. Konno

引用次数: 158

Development and implementation of the effective force testing method for seismic simulation of large–scale structures 大型结构地震模拟有效力测试方法的开发与实现

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0879

C. Shield, C. French, John Timm

{"title":"Development and implementation of the effective force testing method for seismic simulation of large–scale structures","authors":"C. Shield, C. French, John Timm","doi":"10.1098/rsta.2001.0879","DOIUrl":"https://doi.org/10.1098/rsta.2001.0879","url":null,"abstract":"This paper describes the development and experimental implementation of a real–time earthquake simulation test method for large–scale structures. The method, effective force testing (EFT), is based on a transformation of coordinates, in which case the structure is fixed at the base (similar to the set–up for the pseudo–dynamic (PsD) test method); however, in the case of EFT, the method is based on a force–control algorithm rather than a displacement–control algorithm. Effective forces, equivalent to the mass of each storey level multiplied by the ground acceleration, are applied at each respective storey. As such, the EFT forces are known a priori for any ground acceleration record. As opposed to the PsD test method in which the ground displacements to be imposed are affected by the measured structural response as the stiffness changes. As in the case of the PsD test method, the EFT method is suitable for testing any type of structural system that can be idealized as a series of lumped masses (e.g. building or bridge structures). Research has been conducted on a linear elastic single–degree–of–freedom system at the University of Minnesota to develop and investigate implementation of the EFT method. A direct application of the EFT method was found to be ineffective because of a natural velocity feedback phenomenon between the actuator and the structure to which it is attached. A detailed model of the control, hydraulic and structural systems was developed to study the interaction problem and other nonlinear responses in the system. The implementation of an additional feedback loop using the measured velocity of the test structure was shown to be successful at overcoming the problems associated with actuator–ndash;control–ndash;structure interaction, indicating that EFT is a viable real–time method for seismic simulation studies.","PeriodicalId":20023,"journal":{"name":"Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences","volume":"16 1","pages":"1911 - 1929"},"PeriodicalIF":0.0,"publicationDate":"2001-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73060516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 44

Development, potential, and limitations of real–time online (pseudo–dynamic) testing 实时在线(伪动态)测试的发展、潜力和局限性

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0876

M. Nakashima

{"title":"Development, potential, and limitations of real–time online (pseudo–dynamic) testing","authors":"M. Nakashima","doi":"10.1098/rsta.2001.0876","DOIUrl":"https://doi.org/10.1098/rsta.2001.0876","url":null,"abstract":"This paper presents a test system for conducting online (pseudo–dynamic) tests on a real time–scale. A historical perspective is provided regarding the development of such testing, and a real–time online test system devised by the writer is introduced. The proposed system is characterized by (1) use of a digital signal processor now readily available; (2) adoption of the C language to ensure easy programming; and (3) separation of response analysis and displacement signal generation to allow the testing with complex structures. A five–storey base–isolated building model, treated as a six–degrees–of–freedom structure, was tested for various ground motions. The tests demonstrated that the system is able to simulate earthquake responses involving large displacements and velocities as well as complex numerical hystereses. Advantages and drawbacks of the real–time online test are discussed in reference to other experimental techniques: the quasi–static loading test using a predetermined loading history, the shaking–table test and the conventional quasi–static loading online test. Areas that require further research for advancement and refinement of the real–time online test are also noted.","PeriodicalId":20023,"journal":{"name":"Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences","volume":"6 1","pages":"1851 - 1867"},"PeriodicalIF":0.0,"publicationDate":"2001-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90192234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 119

Utilization of multi–axial shaking tables for the modal identification of structures 多轴振动台在结构模态识别中的应用

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0872

U. Füllekrug

{"title":"Utilization of multi–axial shaking tables for the modal identification of structures","authors":"U. Füllekrug","doi":"10.1098/rsta.2001.0872","DOIUrl":"https://doi.org/10.1098/rsta.2001.0872","url":null,"abstract":"A multi–axial shaking table is normally used for earthquake simulation and the dynamic qualification of structures. In most cases the same set–up can also be used for a modal identification of the tested structure. However, this requires the application of suitable modal identification methods. Here, the theory and the basic principles of modal identification by multi–axial base excitation are described. Starting with the relative kinematics and the fundamental dynamic relationships, the specifics of base excitation are explained. Equations for the structural responses and the dynamic forces at the interface are presented and discussed. A survey of identification approaches developed at DLR, Gottingen is given. A frequency– and a time–domain method are described in more detail and illustrated by their application to a laboratory structure. The frequency–domain method is best suited for a general and reliable modal identification, whereas the time–domain method is capable of analysing transient vibrations. Also, the frequency–domain identification of a larger structure is outlined.","PeriodicalId":20023,"journal":{"name":"Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences","volume":"05 1","pages":"1753 - 1770"},"PeriodicalIF":0.0,"publicationDate":"2001-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86484716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

The development of real–time substructure testing 实时子结构测试的发展

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0877

A. Blakeborough, Mary R. Williams, A. Darby, David R. Williams

{"title":"The development of real–time substructure testing","authors":"A. Blakeborough, Mary R. Williams, A. Darby, David R. Williams","doi":"10.1098/rsta.2001.0877","DOIUrl":"https://doi.org/10.1098/rsta.2001.0877","url":null,"abstract":"Full–scale dynamic testing of civil engineering structures is extremely costly and difficult to perform. Most test methods therefore involve either a reduction in the physical scale or an extension of the time–scale. Both of these approaches can cause significant difficulties in extrapolating to the full–scale dynamic behaviour, particularly when the structure responds nonlinearly or includes highly rate–dependent components such as dampers. Real–time substructure testing is a relatively new method which seeks to avoid these problems by performing tests on key elements of the structure at full or large scale, with the physical test coupled in real time to a numerical model of the surrounding structure. The method requires a high performance of both the physical test equipment and the numerical algorithms. This paper first reviews the development of structural test methods and the emergence of real–time substructure testing. This is followed by a brief description of the equipment that is needed to implement a substructure test. Several novel developments in the numerical algorithms used in real–time substructure testing are presented, including a new, fast algorithm which allows nonlinear response of the surrounding structure to be computed in real time. Results are presented from a variety of tests which demonstrate the performance of the system at small and large scale, with either linear or nonlinear test specimens, and with varying numbers of degrees of freedom passed between the physical and numerical substructures. Finally, the usefulness and possible applications of the test method are discussed.","PeriodicalId":20023,"journal":{"name":"Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences","volume":"35 1","pages":"1869 - 1891"},"PeriodicalIF":0.0,"publicationDate":"2001-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79036183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 186

Adaptive control of shaking tables using the minimal control synthesis algorithm 基于最小控制综合算法的振动台自适应控制

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0862

D. Stoten, E. Gómez

{"title":"Adaptive control of shaking tables using the minimal control synthesis algorithm","authors":"D. Stoten, E. Gómez","doi":"10.1098/rsta.2001.0862","DOIUrl":"https://doi.org/10.1098/rsta.2001.0862","url":null,"abstract":"Traditional shaking–table testing has been limited by the effectiveness of conventional fixed–gain algorithms used in their control. These algorithms are normally based on linear models of the shaking table and specimen, whose parameters are assumed to be fixed for the duration of the test. Although the influence of the specimen in the overall system dynamics can be partly removed by fine–tuning the linear controller, this process cannot deal with nonlinear effects and is limited in scope by the expertise of the operator. The minimal control synthesis (MCS) algorithm is a form of adaptive control, which was originally and successfully employed to cope with the nonlinear problems in the field of robotics. The MCS algorithm can tune the controller in real–time without any parametric knowledge of the system to be controlled. This paper describes how MCS has been incorporated within both analog and digital controllers for shaking tables and shows some of the results achieved on tables at the University of Bristol and at Athens Technical University. In both cases, the introduction of adaptive control has noticeably improved the performance of the shaking table, correcting errors by more than 5 dB in some experiments.","PeriodicalId":20023,"journal":{"name":"Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences","volume":"33 1","pages":"1697 - 1723"},"PeriodicalIF":0.0,"publicationDate":"2001-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89908891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 100

The European collaborative programme on evaluating the performance of shaking tables 评估振动台性能的欧洲合作计划

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0861

A. Crewe, R. T. Severn

{"title":"The European collaborative programme on evaluating the performance of shaking tables","authors":"A. Crewe, R. T. Severn","doi":"10.1098/rsta.2001.0861","DOIUrl":"https://doi.org/10.1098/rsta.2001.0861","url":null,"abstract":"This paper describes a concerted performance appraisal of four of Europe's large shaking tables. Three of the shaking tables were capable of controlled motion in all six degrees of freedom, while the fourth was constrained to move in the three translational axes only. The principal study was the fidelity of the input motion at the testpiece. At all four tables this was found to be satisfactory, but, in one case, the time taken for the tuning process was often more than one hour, and in all cases highly trained and experienced operators were required. Even so, the tuning process was ‘out of real time’, which required that the physical properties of the testpiece should not change during the tuning process. This meant that controlled nonlinear specimen behaviour could not be studied experimentally. This was a major drawback, since modern economic design requires use of nonlinear material properties, leading to progressive failure of redundant members, but not total collapse. The studies did, however, have a major beneficial effect in showing that existing control systems were out of date. Further research programmes were therefore started which have already had the major consequence of producing ‘real–time’ control of shaking tables.","PeriodicalId":20023,"journal":{"name":"Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences","volume":"25 1","pages":"1671 - 1696"},"PeriodicalIF":0.0,"publicationDate":"2001-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87608491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 43

Characterization and testing of the Caltrans Seismic Response Modification Device Test System Caltrans地震反应修正装置测试系统的特性与测试

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences Pub Date : 2001-09-15 DOI: 10.1098/rsta.2001.0875

J. Shortreed, F. Seible, A. Filiatrault, G. Benzoni

引用次数: 20