The author presented a review of seismic studies of cylindrical liquid storage tanks in ref. 1 in 1983. Six years have passed since then. During this period, many more studies have been performed, and great progress has been made in tackling problems that were unsolved at that time. Particularly numerous following the Nihonkai Chubu Earthquake of 1983 have been studies on liquid sloshing and long-period ground motions. Studies on the behavior of tanks and the coupled vibrations between soil and tanks have focused on the problem of when the bottom plates of tanks lift off from the foundation. The development of the fast breeder reactor (FBR) has necessitated studies on the seismic safety assessment of coaxial liquid contalners. In this connection, the advances and rends in seismic studies of liquid storage tanks performed after the early 1980s will bb surveyed. Remarkable studies conducted even before the 1980s will also be metioned.

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This paper presents probable developments in CAPP systerns with a knowledge base, in light of the increasing necessity of CAPP for manufacturing systems in the future. It introduces cases of applications in industry, then surveys recent Japanese research on CAPP with a knowledge base from four perspectives : ( 1 ) CAD/CAM interfrce, ( 2 ) furnishing CAPP with additional functions, ( 3 ) knowledge database and knowledge representation, and ( 4 ) research and development of specialized CAPP systems (expert systems). In the last section, the paper describes two directions in which research is heading at present : ( 1 ) developing CAPP with a knowledge base suitable for IMS (intelligent manufacturing systems), and ( 2 ) further analyzing thinking processes of experienced proeess planners.

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A flow visualization study of the shear layer movement beneath a submerged, vertical, flat-bottomed gate model with underflow and which undergoes forced streamwise vibration of fixed amplitude and frequency is presented. Computer simulation based on the flow visualization photos, coupled with measured discharge flow velocities and hydrodynamic pressure distributions on the gate, permits the estimation of the fluctuating discharge coefficient and the phase lag between the fluctuating discharge and the gate motion. The motion of the downstream portion of the shear layer is shown to correlate Well with the observed discharge fluctuations. A mechanism of energy transfer for self-excited vibrations of vertical gates positioned above a horizontal bed is identified. The excitations due to the pressure distributions along the upstream and downstream faces of the gate are shown to be approximately equal.

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A systematic synthesis of planar mechanisms with revolute pairs is carried out with consideration given to tolerances of pairing elements. Namely, the optimum tolerances of holes and shafts which constitute revolute pairs in the mechanisms are determined with consideration of variations of clearances of pairs so that the output errors of the mechanisms may be minimized. As a practical example of multilink mechanisms, the optimum tolerances of the pairing elements of planar six-link mechanisms are determined, and it is revealed that the maximum output errors are reduced up to approximately half the level of those of mechanisms which have the same clearances at every pair.

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A method is presented for the determination of sensor and actuator positioning and feedback gains for the active vibration control of flexible structures. This method is based on the minization of the minimum quadratic cost functional in the standard optimal control. The optimal criterion is determined via Riccati equations, and it is minimized with a recursive quadratic pfogramming algorithm with respect to sensor and actuator positioning parameters. The application of this method to a cantilever beam yields several dislocated sensor and actuator locations which are locally optimal. An extension to a case in which modal filters are used is also examined. In this case, the location of the actuator is found to be more sensitive than that of the sensors. This method has clear physical meaning and the flexibility to allow varying of the weighting matrix.

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The authors have developed a general-purpose simulation system for the design of link mechanisms. Topological and Kinematic analyses have already been referred to in the preceding paper. In this paper, methods for the dynamic analysis of link mechanisms with controllers, such as transient response and vibration analysis, are proposed. Both the characteristics of the control system and the equations of motion of the mechanical system are automatically and simultaneously transformed into nonlinear state equations. In transient response analysis, for example, the responses of joint displacements, etc., are calculated by the numerical integration of these equations. In vibration analysis, the state equations are linearized around the desired trajectory to calculate the eigenfrequency, mode shape, and transfer functions. The proposed methods were applied to an industrial fobot, and the effectiveness of the methods was ascertained.

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For the purpose of decreasing the lower critical speed of circular cylindrical shells which are used in centrifugal separators for uranium enrichment, and rotating at higher speeds, we consider circular cylindrical shells connected to bellows. Vibration analysis of circular cylindrical shells connected to bellows is carried out by the substructure synthesis method for various numbers and dispositions of bellows, and the optimum ones are examined. Moreover, the transfer matrix method, by which the critical speeds are simply obtained, is described, and the results are examined by the substructure synthesis method.

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The paper presents a method of identifying the global modal parameters of a mechanical structure from the free decay responses, which is based on the state variable method expressed in the form of a difference state equation. A recursive algorithm is proposed for calculation of the state transition matrix. The modal shapes of a large number of stations for each mode are obtained by making use of the data acquisition system with a few channels, which results from the uniformity of the normalized modal shapes. The generalized mathematical model of the method is related to the other time domain methods. As illustrative examples, the method is applied to the identification of global modal parameters of a free-free straight pipe and a "T"-shaped plate structure. The identified results are in good agreement with the analytical ones.

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This paper presents the possibility to improve both the dynamic stability and the ability to steer around curves by truck parameter control for rail vehicles. According to the direction of motion, the structure of the trucks such as the primary stiffness, link mechanism, and the arrangement of independently rotating wheels is changed, which is longitudinally asymmetric. In the case of interwheelset structure, perfect steering is possible but are generally incompatible with that of the high hunting stability. Both the hunting and the curving performance have been improved by the use of the trailing axle equipped with independently rotating wheels. Moreover, there is a possibility to achieve the compatibility between these two requirements.

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The geometrical configurations of statically determinate trusses having the same topology but different member lengths are not the same. This suggests that the truss structure may work as a flexible arm by actively changing the length of each member, resulting in a highly multiple-degree-of-freedom system, with each member contributing one degree of freedom. The aim of this paper is to establish the fundamental concept and the formulae to describe the dynamic motion of the truss-type arm system. The incremental relationship for kinematic motion is described first. A Lagrangian approach is used to establish the equations of motion within the context of an extended matrix structural analysis; the kinematic degrees of freedom are the same as those of the Structural deformation. Numerical simulations of the kinematic and elastic motion of the arm are included.

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In this paper, the Haar transform is applied to vibration signal analysis and system condition monitoring. Based on the Haar transform, the "impulse index" is defined and used as the discriminant for the description of vibration signals. The impulse index offers information about the average power intensity compressed in each equivalent sequency group. It can be obtained conveniently and quickly by means of fast computational algorithm of the Haar transform. The computer simulation data of the output signals of nonlinear models with single degree-of-freedom are used to prove the effectiveness of the impulse index. The results are compared with those obtained from FFT power spectral density and are shown to be effective.

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The parametric resonance of an axisymmetric shell-lumped weight system subjected to periodic acceleration in the radial direction is analyzed. Symmetric and asymmetric free-vibration modes of the system are derived using the free-vibration modes of the axisymmetric shell without lumped weight. The aforementioned eigenmodes are calculated by employing a conical shell finite element. Modal Mathieu equations of the system are derived, and the parametric resonance regions of the system are calculated using Bolotin's method, considering the effect of translational motion of the lumped weight in the radial direction. Also, a circular cylindrical shell with a lumped weight is experimentally investigated using a vibration table. Numerical results of the parametric resonance regions of the system show good agreement with experimental results.

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A new technique to obtain the viscoelastic property of lubricants at high pressure over 2 GPa is proposed. The lubricants tested are BCCM and DMP, which have high viscodity-pressure coefficients. From the difference of the ruby fluorescence wave length between the (0001) and (1120) ruby plate in a diamond-anvil apparatus, shear stress relaxation can be observed. By applying a Maxwell viscoelastic model for the relaxation analysis, an extremely high viscosity ( over lO¹⁵ Pa·s) is obtained and is almost fitted with the extrapolated value of the existing one. Bulk viscosity and elastic modulus are also obtained and are consistent with the existing values.

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Viscosity of several synthetic lubricants is measured in a diamond-anvil high=pressure cell by the falling sphere method at elevated temperature. Viscosity-pressure coefficients of bicyclohexylcyclohexylmethane, dimethylsilicone and a mixture of them, which are important in elastohydrodynamic lubrication and traction coefficient, are obtained. In order to discuss the property of the mixture, the Wright method is applied and shows agreement with the present data. Viscosity-temperature characteristics under high pressure are also discussed using Walther's equation, and this equation proves to be effective even under high pressure. Factors relating the viscosity=temperature property of the mixture are close to those of dimethylsilicone.

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Tightening pressure of gland packings decreases with time owing to stress relaxation of the packings. In the first step toward the analytical prediction of the stress relaxation in real tightening operation of gland packings in stuffing-box seals, the relaxation behavior of gland packings is examined both bxperimentally and theoretically. Stress relaxation tests were conducted on kland packings of asbestos and graphite. A viscoelastic model is presbnted for a dbscription of the stress relaxation of packings. This model can simulate satisfactorily the stress response of packings, especially in repeated tightening operation.

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In order to obtain as large a delivery as possible without changing the inner space VC of a gear pump casing, the authors introduced a method of designing and producing gear pumps with the number of teeth from 𝒵₁ = 𝒵₂ = 2 to 5. They presented a new tooth profile of helical gears suitable for pumps producing no fluctuations in delivery. Equations were derived for calculating the theoretical delivery V_th of the gear pumps and also the thrust which occurs on the gears. Experiments were conducted using four kinds of trial gear pumps with 𝒵₁ = 𝒵₂ = 3 or 4. In the case of the gear pumps with 𝒵 = 3 and a transverse module of 15.65 mm, the volumetric efficiency was about 98% and the total efticiency was about 90% when the pump was operated at about 1.5 MPa using a machine oil as the pumping fluid. The volume ratio V_th/V_c of the trial gear pump was about 0.5, while it was about 0.2 in the case of a conventional gear pump with almost the same delivery.

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For slow external gear pairs with parallel axes, service life often depends on wear. The amount of wear is affected by the specific slidings. Therefore a design tool in limiting Wear is a decrease of specific slidings obtained from suitable values of the addendum modification coefficients. The advantages offered by addendum modiflcation have been evaluated by a computer program. It has been pointed out that they may be many. The program outputs show that using the same material for both gears is a suitable choice in some conditions, but in others, different materials should be chosen. If helical gears are adopted instead of spur gears (spur gears are commonly used when the speed is low), further advantages may be attained by a suitable helix angle value. On the basis of the above results, the best approach for an optimum design to lessen wear has been outlined.

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This paper presents a study on the root stresses of thin-rimmed spur gears due to press-fitting. The stresses of the gear were analysed by means of the finite element method (FEM). In this analysis, elastic contact between the gear and the shaft or bush was taken into consideration. Also, the root stresses were measured. The effects of the rim and bush thicknesses, the number of teeth, and the interference on the stresses at the root fillet and at the contacting surface were examined. On the basis of these computed results, a practical formula for the mdximum true root stress of a thin-rimmed spur gear press-fitted to a shaft was derived.

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In order to efficiently obtain mirrorlike ground gears, the authors designed and made a computer numerically controlled (CNC) gear grinder. For obtaining the desired surface finish, a cubic boron nitride (CBN) grinding wheel with a medium grain size was used under creep-feed gririding conditions with grinding fluid. The profiles of the gear being ground were generated by a rolling motion produced by a master worm gear and a high-accuracy ball screw. The trial gear grinder could produce spur gears with mirror-like tooth surfaces having a roughness of about 0.2μm Rmax. By controlling the two servomotors, gears with any type of tooth profile modification could be ground easily. Using the same principle, an intermittent grinding process was introduced for preventing grinding burn under severe grinding, and ground gears with modules of 2 and 3 were made without a cutting process.

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A new type of cylindrical gear which is called a zigzag-toothed gear is proposed.This type of gear has the same cross-sectional profile as a conventional spur gear, and a tooth trace which is arranged in zigzags on a cylindrical surface. A specigl configuration, such as a zigzag-toothed gear, improves the material flow in gear rolling so that there is a more precise form of tooth. In rolling this type of gear, the axial flow of material, which seems to be indispensable to complete the gear rolling but never appears in the rolling of conventional gears, is induced. Additionally, this type of gear has the advantage of maintaining good conditions for the lubricant and the ability to support some thrust load.

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The problem of the product of two independent probability variables which are normally distributed was theoretically analyzed using the confidence limit ellipse. By applying 𝓏 = x/y type problems to a disk clutch, the limit of transmitted torque was rationally calculated. On the axial tension control in bolted joints for the 𝓏 = x/y type problem, experimental analysis concerning bolt tightening by the calibrated wrench method was carried out under dry, oil and anaerobic adhesive conditions. For this type of problem, the proposed method is applicable in the case in which the hyperbolic relation can be treated linearly. For the distribution of product 𝓏, the method for the calculation of probability P_f, when 𝓏 did not exceed a limit, was shown. From the result of the analysis by the proposed method, it was found that the maximum and minimum values in the scatter of the product 𝓏 by the conventional method resulted in the use of a higher confidence limit level that corresponded to √(2) times greater in the percentile value in the standafd normal distribution table.

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The concept of the new dynamically reconfigurable robotic system (DRRS) are its realization as the cell-structured distributed robotic system CEBOT are discussed in this paper. CEBOT can reconfigurate itself to optimal structure depending on purpose and environment. These robotic systems are very advantageous for space robotics, since the available resources are limited in space. This robotic system is possible owing to the use of separable self-controlled units called "cells" ; thus the robotic system is called a cell-structured robot #(CEBOT). CEBOT has unique features such as a dynamically reconfigurable structure, on-line task adaptability, fault tolerance, etc. With simple elementary cells clustered into large structures or modules, complicated tasks can be executed (this concept is found in biological organisms). We propose this concept, control and sensor system structure, and automatic approach control. The efticiency of CEBOT is shown by the results of automatic approaching, connecting and separating experiments.

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This paper describes an automatic organism recognition and identification method, using image processing based on an expert system for application in a micromanipulator system. Since organisms under a microscope all appear different, are in motion and have time-dependent shapes, the conventional pdttem-matching method used for industrial products can hardly be applied. The proposed new method is based on segmentation of the organism images (organism image segmentation method; OISM) and takes advantage of characteristic segment features which are independent of individual size and length. Their complicated shapes are divided into basic shape segments (defined in this paper), such as lines, circles, and ovals. The relations between segments are analyzed and described automatically in the data base of the expert system. Organisms can then be expressed simply in a set of segments their individual differences can be avoided. Tracking the movement of an organism by its image is also shown in thid paper. The effectiveness of this method is confirmed by experimental results.

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In this study, the random behavior of time-lag durations of discharge pulses are investigated for different machining conditions in Electric Discharge Machining(EDM). Gamma model is shown to be a suitable statistical model to represent the statistical characteristics of experimental time-lag distributions. For different machining conditions, variations in shape and scale factors of the two-variable gamma model are calculated and compared with the best fits found by trial and error.

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