複素係数ディジタルフィルタに関する研究

博士論文

The design of the friction-type connections fastened with high-strength bolts has been made based upon the traditional elastic vector analysis, despite the fact that the resisting mechanism of the friction-type is different from that of a riveted connection. Discussion has been provoked with respect to the actual behavior of the friction-type connections and the lack of the conformity in the existing design provisions. Rationalization for both design and construction corresponding to the multi-plied and complicated reaction forces in parallel with the tendency of structures being steered into directions of giantism and diversification in recent years has strongly been required with respect also to the friction-type connections. As the structural design concept is varied, the working stress method is converted into the limit state design method via the ultimate design method. This compels the connection design to comply with a new situation. With such backgrounds behinds us, successive experimental works relating to the friction-type connections have been intensively carried out in the individual researching fields in our private, official and academic circles in recent years. However the experimental studies are insufficient as a means of establishing the verification between the cause and effect, due to the existence of too many of factors to determine the dynamic configuration. Moreover to extensively systematize the diversified kinds of excessively large-sized connections and to get to work for the practical design, a huge amount of time and labor together with expense is expected to be required. This means that it is substantially impossible to systematize the wide-variety connections just by means of experiments. Thus analytical studies are earnestly required to solve such a problem, and an analytical model with which the explanation of the actual slipping behavior is to be provided is desired to be developed. In this paper, slipping resistance characteristics of the friction-type connections with high-strength bolts are explained from the standpoints of both the experiment and the nonlinear analysis utilizing a discrete model. Further-more establishment of a more rational design method availing itself of the utmost of the solution of the various kinds of problems previously described and the intrinsic characteristics of the friction-type connections is intended. In the analytical study, new inelastic analysis method utilizing two discrete model, RBSM (Rigid Body-Spring Model) and PIFESM (Parabolic Iso-parametric Finite Element-Spring Model) is developed. Proposed method is able to simulate partial slip behavior of the friction-type connections under every sorts of loadings, and accordingly the method is available to investigate shape effects, combined effects of web connection and flange connections, slip strength under eccentric loadings and fatigue strength. Depending on the facility required of the practical engineer, the results obtained in this study are shown in a graphic form and/or tabulated form. This paper consists of nine chapters and each chapter is outlined below. Chapter 1 gives an outline of former studies on slipping problem of the friction-type connections, and explains the subJect of this study. A list of principal symbols and terminology used in this paper is presented in this chapter. Chapter 2 develops new discrete models (RBSM and PIFESM) for slipping problem of the connections. These models are able to simulate discontsinuous partial slipping behavior of the connections up to the state of major slipping. The shear spring, Which connects base plate and splice plate, has nonlinear properties that the shear force, when itreaches critical shear force against local slip. holds the same value of critical one. As the installed bolt tension changes with longitudinal normal stress by Poisson's ratio, the critical shear force also changes. The initial shear-spring constant is determined by setting the total shear strain energy in the spring equally to the one in the plates with two compensation factors. Chapter 3 includes the analytical method and programing technic. Linear relationship between shear force and relative displacement is no longer valid once a local slip occurs. To obtain the equilibrium position of the nonlinear system, the direct iteration method is used. Chapter 4 verifies the proposed analytical method by comparing the theoretical results with the results of test carried by Hlonshu-Shikoku Bridge Authority. Major slip load, bolt force, load-displacement relationship and normal stress are compared, and there is a good agreement. A few characteristics of the friction type connections is obtained through this verification process. Chapter 5 shows existence of some sort of correlation between the fatigue strength and the partial slip load of the edge bolt. According to this correlation, an attempt is made for prediction of the relative fatigue strength of the connections from partial slip stress of the edge bolt. Chapter 6 presents application to shape effect　problem　of　the　connections　and　shows　fluctuations　in　the　slip　loads　exerted　by　the　factors　among　them　such　as　the　cross　sectional　dimensions　of　plates,　joint length, bolt arrangement and so forth. Chapter 7 describes frictional resistance characteristics of the plate girder connections and proposed a more reasonable and convenient design method. The discussion is concentrated on the effects of combined web connection and flange connections. Two types of the combined connections are loaded in pure bending. The results show that the web connection and flange connection work organically and complimentarily to each other. The experimental results are confirmed by computer simulation using quasi three dimensional analytical method. Chapter 8 presents slip behavior of the friction-type connections acted upon by the in-plane combined moment and direct shear and recommends a strength approach with modified coefficients for plate girder connections ande ccentric connections. Chapter 9 includes the conclusions obtained from this study.

東京都立大学, 1991-03-14, 工学博士, 乙第763号