The application of an active control, such as four-wheel steering and active suspension, to cars has changed not only the vehicle dynamics design but also the dynamic characteristics of cars. Active four-wheel steering reduces the sideslip angles of the wheels, thus the unnecessary yawing motion of cars decreases and the time lag in the dynamic response to handling also decreases. An active roll control of the car body makes use of type properties to the best advantage. The four-wheel steering and active suspension upgrade the dynamic performance of cars, and expand the limit performance of dynamics. An adaptive control, integrated control and intelligent control will be introduced to cars, completely changing vehicle dynamics of cars in the near future.

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A new technique of identifying nonlinear multi-degree-of-freedom systems has been presented. The basic procedures of this technique are : (1) obtaining the data of a periodic external force applied to the system and of the periodic steady-state response induced by it ; (2) expressing the nonlinear terms of the system in the form of polynomials with unknown coefficients ; and (3) determining the unknown coefficients by expressing the necessary quantities in Fourier series and applying the principle of harmonic balance. Some examples are given to show the applicability of the technique presented.

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This paper proposes a new vehicle that runs in small pipes with an inner diameter of less than 100 mm in order to maintain and inspect them. Many bristles are attached at an angle to the surface of the vehicle. Eccentric weights at both ends of the vehicle are rotated by a motor inside the vehicle. Since this structure does not require wheels or reduction gears, it has good potential for miniaturization. First, the sliding velocity of each bristle and its friction are discussed. Then, running simulations and experiments are conducted using a vehicle with 16 bristles in order to clarify the relationship between the running velocity of the vehicle and the angular velocity of the eccentric weights. It is shown that the vehicle runs smoothly inside a small pipe and that the calculated running velocity agrees with the experimental results.

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In order to find some way to detect a transverse crack due to fatigue in a rotating machine, we have investigated experimentally and theoretically the change in the resonance curve caused by the occurrence of a crack. The experimental apparatus is a vertical rotating shaft system in which an elastic shaft with a disk is supported simply at both ends. In experiments, the amplitude curve and the phase angle curve were measured in the neighborhood of the major critical speed for various angular positions of the rotor unbalance. The results show that the shape of the resonance curve changes extremely due to the direction of the unbalance, and an unstable region appears when the unbalance exists in the same direction as the crack. It is shown that this phenomenon is explained theoretically by combining the characteristics of the unsymmetrical shaft and that of the symmetrical shaft or by considering rotating nonlinear spring characteristics.

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The bow force necessary to maintain steady vibration of a bowed string is greatly increased, and its fluctuations are severely intensified by the presence of inharmonicity due to flexural stiffness of the string. Timoshenko's beam theory gives a slightly smaller estimation of inharmonicity than the ordinary beam theory and decreases the necessary bow force considerably. Meanwhile, the internal friction of the string in bending and torsional motions and the compliance and damping of the bow mitigate the effect of inharmonicity that comes from the stiffness of the string. These factors are related with the configurations of the velocity resonance curve of the string, especially of its bottom parts in the higher frequency range. Along with some of our previous reports, the sound energy transmitted through the bridge to the body of an instrument is considered in this analysis, in which a Fourier series solution by means of series transformation for a piecewise-linear system is used.

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In this paper, Ieakage-flow-induced vibrations are discussed in the case of a one-dimensional, narrow passage in which one of them is vibrating harmonically with a small amplitude. First, the fluid-dynamic forces acting on the walls of the tapered passage are analyzed. Second, the transfer matrix method is applied to the calculations of fluid-dynamic forces in the case of an arbitrary-shaped passage. The fluid-dynamic coefficients in the case of a tapered passage are calculated to check the accuracy of this method, and those in the case of the passage with a step are also calculated. It is found that if the cross-sectional area of the upstream passage is smaller than the downstream one, both negative fluid-dynamic stiffness and negative fluid-dynamic damping can occur in both the cases of a tapered passage and a passage with a step.

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Oscillations caused by solid friction in a hydraulic driving system are treated theoretically. The system includes a table lying on a rectilinear sliding surface, an actuator cylinder, a 4-way servo valve, a relief valve, and an oil pump. The solid friction force considered is assumed to vary with the relative sliding velocities between the table and sliding surface, namely, the friction-velocity charscteristic is given by a polygon having two straight-line segments and the critical value of static friction is equal to the value of kinetic friction without slipping. The stick-slip motions of the table are analyzed considering the 4-way valve pressure-flow characteristic, the friction-velocity relation, oil compressibility and the sizes of the hydraulic driving elements. Several types of limit cycles and the regions in which they occur are shown in figures according to the parameters mentioned above. Lastly, the steady-state displacement waves of the table are described and the curves of amplitudes and their periods are given.

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This study presents an analytical method to reveal the dynamic behavior of a scroll-type compressor of small capacity. The calculated results are summarized on the basis of the gast-orque fluctuation, the crankshaft rotary behavior, the constraint forces at each pair of machine elements, the unbalanced forces of inertia, the compressor vibrations, the mechanical losses and the mechanical efficiency. It is concluded from this study that the scroll compressors have revolutionarily well-balanced dynamic characteristics in their vibrations, but have poor mechanical efficiency compared with the commonly used one-rolling-piston-type rotary compressors.

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A driven shaft system consists of a flexible shaft with circular section and a rotor. The flexible shaft is supported by a universal joint at one end and a bearing at the other end. When a drive shaft rotates with a constant angular velocity, the driven shaft is subjected to the angular velocity fluctuation governed by a joint angle between the drive shaft and the driven one. However, when the driven shaft vibrates laterally and causes bending in itself, the joint angle is slightly changed and the rotating speed deviates. This is why the lateral-torsional coupled vibrations become unstable at the same time. These unstable vibrations occur when the drive shaft rotates at a speed of nearly half the sum of the natural angular frequency for the lateral vibration and the one for the torsional vibration.

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The authors analyze the coupled vibrations between wheels and a rail in the horizontal direction, taking Kalker's linear creepage theorem into account. They calculate the steady-state responses of the Shinkansen wheels and a 60 kg rail at the points of contact and investigate the individual characteristics of a rotating wheel theoretically and experimentally. It is found that the rail is strongly influenced by the wheel characteristics in the coupled vibration while the wheels themselves retain their individual characteristics.

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Nitrided steel gears having three kinds of standard pressure angles were fatigue-tested using a power circulating gear testing machine, in order to elucidate the effect of standard pressure angle on the load carrying capacity and the failure mode of the nitrided gears. The relation between the tooth profile change and the dynamic performance of the gear in the fatigue process was also investigated. The failure modes were tooth breakage at the fillet or grinding notch under a lower pressure angle and higher load and spalling or tooth breakage due to spalling under a higher pressure angle and 10wer load. The fatigue strength for a normal load increased with an increasing pressure angle. The changes in the tooth profile and the dynamic characteristics during the fatigue process were slight.

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A precise analysis has been made on the profile of the relieving tool of the type 3 worm hob. Firstly, the type 3 worm thread surface, which is normal to the basic thread surface of the hob, is chosen as the helical cutting face of the type 3 worm hob. Secondly, the calculation method for the profile of the relieving tool for this worm hob is obtained. Thirdly, the calculation method for the deviation from the tangent at the pitch point on the profile of the relieving tool is clarified. Then, the experimental manufacture of a relieving tool is performed by applying these calculation methods to a numerical example of the type 3 worm hob. The theories in this analysis are verified by practical relief cutting of the type 3 worm hob with the relieving tool. The necessity and the effectiveness of these calculation methods are confirmed.

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The effect of surface roughness of turned surfaces have been investigated on the compressive stress for allowable gas leakage through static seals (metal-to-metal seals and metal gasketed seals) . From the results of gas leak tests, it was found that the desirable compressive stress for sealing had to be nearly equal to 1.5 times the tensile strength of the gasket material, regardless of the extent of surface roughness (R_max≒0.2∼220 μm).

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A new method of direct numerical calculation for the fluid film lubrication problem is presented in this paper. The present method is derived by applying the boundary fitted coordinates system to the divergence formulation (DF) method. The present method makes it possible to deal with an arbitrary configuration of a lubricated surface, so the disadvantage of the DF method compared with the finite element method is solved. The present method has the following advantages : (1) An arbitrary configuration of a lubricated surface can be calculated. (2) Computer programing is easy. (3) The scale of computer program and cpu time are small, so calculation by a personal computer is possible.

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The running accuracy characteristics of an externally pressurized gas thrust bearing will be theoretically studied in the course of this research in relation to the machining deviations of forms of the bearing and the rotor. For the first step of the research, the load-carrying capacity fluctuation of the bearing, which may result in axial run-out of the rotor, is analyzed in this report. As the factors causing the load capacity fluctuation, two aspects of machining error of the bearing are taken into consideration : one is the perpendicularity of the rotor end surface, and the other is the size deviation of the gas supply holes. The point source solution of the Reynolds equation yields the load capacity characteristics under these form errors of the bearing.

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With the development of the carbide hobber and improvement in the manufacturing of the carbide hob, carbide hobbing has found extensive use in industry. For example, annealed gear blanks which are often used in mass production can be carbide-hobbed without trouble. In addition, it can also be adopted to hob gear blanks of heat-treated or hard materials which have thus far proven to be difficult to cut using high-speed steel hobs. However, in the case of carbide hobbing for gear blanks which have been heat-treated, damage from chipping or thermal cracks, seen as an increase of relief wear, will occur during the lifetime of carbide hob because of unsuitable cutting conditions. In this paper, the authors have investigated the cause of and countermeasures against damage by systematically classifying the shapes of damage on the cutting edge in carbide hobbing.

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Computer simulations of roll-finishing by a die-wheel with profile and longitudinal modifications were carried out to determine the optimum tooth form of a die-wheel. The simulation results revealed that a die-wheel should be modified by hollowing the tooth form at the position corresponding to the hollowed part of a tooth form roll-finished by an unmodified die-wheel, and so was projected at the position corresponding to this corresponding position. Then, the experiments of roll-finishing were carried out using the modified die-wheel. The results of these experiments showed that the profile and longitudinal modifications of a die-wheel were very effective if altered in the manner mentioned above ; such a die-wheel gave a fairly good tooth form. Further more, the experimental results showed that an interference between the tooth tip of die-wheel, and the tooth root and bottom of work-gear should be prevented, e. g., by tip relief of the die-wheel.

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A ruby pressure sensor, detecting hydrostatic pressure (up to 100 GPa) by the shift of ruby R₁ R₂ fluorescent wavelength, is compressed by uniaxial stress generated by diamond anvils with a lever-type loading apparatus. Two ruby plates, each having (112^^-0) and (OOO1) crystal planes are loaded in order to investigate anisotropic sensitivity. The sensitivities for pure uniaxial stress are obtained from the experimental data and FEM analysis of the ruby. Obtained sensitivities for (112^^-0) and for (OOO1) crystal planes are 0.141 7±0.002 O nm/GPa and 0.077 9±0.003 2 nm/GPa respectively in the R₁ fluoresence line. These values are indispensable in studying the stress field of a pressure chamber ; and the utility of the ruby sensor will be expanded.

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A numerical method to simulate the high-speed free forming of a clamped circular disk in an electromagnetic forming system using a flat spiral coil is presented. The method combines field penetration into the disk and dynamic elasto-plastic deformation of the disk. The spiral coil is approximated by coaxial circular loops carrying the discharge current from a capacitor bank. The penetration of the magnetic field of the coil into the disk is formulated as a boundary-value problem for the diffusion equation. Magnetic field, eddy currents and electromagnetic force density in the disk are calculated. An equation of motion for the disk loaded by the magnetic force is combined with the field equation as well as an equivalent circuit equation. Plane stress condition is assumed. Strain-rate effect on the work-hardening law of the disk material is taken into account. An experiment on the free bulging of annealed aluminum disks is also presented, showing fairly good agreement with the numerical solution.

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An expert CAD system is developed for the design of marine power plants using the Artificial Intelligence (AI) concept. Firstly, the design process is discussed generally from the view point of applying the AI technique effectively to the design process. It is found that a hybrid-type expert CAD system coupled with the AI technique and the design optimization method is most effective for this type of CAD system. The system architecture of the devoloped CAD system consists of the knowledge base for the design rules, the frame-type data base of the plant machinery, and the mathematical optimization process. Through system execution, it is ascertained that the system is effective not only as a tool for plant design but also as a tool for instructing inexperienced designers.

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In recent years, a tendency towards varied and short-life merchandise has led to progress in Factory Automation (FA) in industry. The problem of plant and process layout is one of the most significant and involved engineering problems in FA. This paper describes a new method for solving the layout problem. We discuss the arrangement of manufacturing processes in which manufacturing goods are produced by repeating basic processes. The most suitable arrangement in manufacturing processes is investigated to make use of Graph Theory. We use co-factors of graph theory and the adjacent matrix to solve the problem efficiently. The applications of this method to several examples of layout problems are shown and the effectiveness of this method is demonstrated for a LSI product.

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