This paper presents analytical results of non/dimensional frequency parameters and mode shapes of vibration for twisted and cantilevered thick plates with spanwise tapered thickness. The method used is based on the three-dimensional elasticity theory and the Rayleigh-Ritz approach including the effects of transverse shear and rotary inertia. The effects of varying the thickness and the twist angle on non/dimensional frequency parameters and modes of vibration are studied. The present results are compared with results in the literature, and the usefulness of the present method for analyzing the free vibration of twisted plates having spanwise taper is verified.

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It is a very difficult problem to determine the stability of the periodic steady-state vibrations generated in a large-sized nonlinear system with multiple degrees of freedom. In order to overcome such difficulty, a new practical method to accurately analyze the stability of the periodic solutions obtained from the method of harmonic balance is developed for a nonlinear structure connected in series. The present method is mainly based on the argument principle, and is applicable to the stability analysis of any multi-degree-of-freedom system excited parametrically. By introducing the same treatment as that of the incremental transfer influence coefficient method into the computation process of the present method, the computation speed is improved and the memory size required in the computation is considerably reduced.

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It is very important to predict natural frequencies and modes of a structure vibrating with fluid in the design of turbomachines such as water turbines and gas turbines. As for reversible water turbines, it is necessary to analyze complex and large-scale problems such as coupled vibration of a runner and an upper cover which sandwich the water in a narrow space. Using the conventional method it is quite difficult to solve such problems because of the memory limit of computers due to the increase in the number of degrees of freedom of the system. This paper proposes an analysis method for prediction of natural frequencies and modes, which enables deduction of the size of the matrices by introducing the modal method for both structure and fluid. The objective of this method is to obtain converged added mass for necessary modes by iterative modification of this added mass in modal coordinates until the orthogonality is satisfied. The validity and the usefulness of this method are confirmed by comparison with measured data.

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This paper deals with nonstationary rotor vibration due to collision with an annular guard during passage through a critical speed. An unbalanced Jeffcot rotor is accelerated at a constant angular acceleration and strikes the annular guard supported by a spring and damper. This dynamic process is calculated by the Runge-Kutta method under various conditions, and the effects of several parameters on the process are discussed. It is assumed in the calculation that a contact force and a friction force are exerted during collision. The contact force or the impulse of the contact force is estimated by the following two methods. (1) By using both the law of conservation of momentum and the coefficient of restitution, the impulse of the contact force is obtained as a momentum change before and after collision. (2) The contact force is assumed to be proportional to an overlapping displacement between the rotor and the guard.

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A simulation method was studied to calculate the vibration response during seismic excitation of a group of hexagonal bars installed in a restraint. Since impact phenomena take place between adjacent bars, or between a bar and a restraint, nonlinear force caused by the impact should be considered in the response calculation. The simulation method is a combination of the mode superposition method and the pseudo external force method. Time integration is carried out using the method proposed by Nigam. The nonlinear forces at the next time step can be determined through matrix calculation by introducing influence coefficient matrices which express the influence of impact forces on intersections at impact points. In this report, the influence coefficient matrices are expanded for hexagonal bars in a two-dimensional arrangement, by taking the impact direction of each impact point into consideration. In order to verify the above method, the calculated results were compared with experimental ones. The two results for maximum impact force were similar.

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The simplest exact solution of free vibration of a string with timevarying length is presented. Taking into account virtual sources of waves which can be assigned to reflecting waves, an extended Stokes' formula is obtained. Coordinates of the virtual sources of the waves which can be observed at (t, x) are given by (0, -at+x) and (0, at+x). Using values of the virtual sources, the solution at (t, x) can be obtained.

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The effect of mechanical vibration on the diastolic performance of the left ventricle is simulated numerically on the basis of the model of Beyar and Sideman, in which the contraction mechanism of the myocardium is taken into consideration and the left ventricle is modelled by an ellipsoid of revolution. The model is improved by adding the effect of the reduction in the contractile force due to mechanical vibration and the effect of diastolic failure of the left ventricle. This simulation gives the same result as the experiment, in which the pressure during systolic period is increased and that during diastolic period is depressed markedly by the mechanical vibration only during the diastolic Period.

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This paper describes the modal analysis of a thick cylinder with both ends free, based on Mindlin's thick plate theory. The equations of vibration of the thick cylinder were derived in consideration of shearing deformation and rotatory inertia, and were simplified and solved under assumption of the axial and circumferential deformations of the neutral cylindrical surface. Except for some low modes, the calculated natural frequencies agreed well with the values obtained by experimental modal analysis and with the modal analysis by use of Finite Element Method. Also, the calculated mode shapes compared well with those obtained by FEM modal analysis.

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This paper proposes the vibration control method of flexible structures arranged in parallel. In recent years, vibration control of a flexible structures using an active dynamic absorber has increasingly been utilized in practical applications. In the future, as the structure becomes more advanced and more flexible, its natural frequency gradually becomes lower. Thus, it will be difficult to assume enough force for vibration control using an active dynamic absorber. The authors proposed the method wherein two structures arranged in parallel are controlled actively using two actuators set between them. In general, a reduced-order-model is necessary to design a controller using the LQ control theory. Using the modeling method proposed here, reduced-order model of the 2-2 degree-of-freedom parallel structures can be easily fabricated. Using a root locus plot, the relationship between weighting parameters and control effect in the LQ control theory is clarified. It is demonstrated that this control method is able to control vibrations of 2-2 DOF system without the spillover instability, by simulation and experiment.

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We propose the design method of an active dynamic absorber for controlling vibrations of multi-degree-of-freedom systems using the LQ control theory. The reduced-order model of multi-degree-of-freedom systems is made using the new modeling method proposed here. First, in order to obtain generality for designing the control system, the state equations of the structure included an active dynamic absorber, and the state feedback gain matrix and weighting matrix are represented by the nondimensional equations. Secondly, the relationship between the vibration control effects and parameters of the weighting matrix is clarified for designing. The design data are prepared as the nondimensional root locus. Effectiveness of the active dynamic absorber designed by this method is demonstrated experimentally.

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Recently, the necessity of lighting and high-speed for the machines is increasing. This paper concerns the vibration and motion control by the the control system which combined a servo controller with a hybrid dynamic absorber. In our method, the vibration control and the servo control are designed independently. Firstly, the dynamics of the tower structure and the servo motor are modeled. It is shown experimentally that although vibration control by the servo controller alone causes the instability due to nonlinear elements such as the friction or the rattle, the hybrid dynamic absorber is hard to cause this sort of the instability. On the comparison of the vibration control effect and the control force, the hybrid dynamic absorber needs the less force. Finally, to know its effect we evaluated the motion (triangle wave, sine wave) of the flexible structure. Effectiveness of this vibration and motion control method to the flexible structure is demonstrated by simulation and experiment.

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This study deals with a nonstationary analysis of energy absorption capacity for various types of response control systems for structures such as building subjected to the earthquake ground motion. In this study, a passive tuned mass damper(TMD), an active mass damper(AMD), an active tuned mass damper(ATMD) and an active tuned mass damper with lever and Pendulum mechanism(APLD) are considered. This analytical study is based on expanding the Kanai-Tajimi earthquake model to include the nonstationary nature of the amplitude of earthquake ground motion. The mean cumulative absorbed energy, mean cumulative input energy and mean cumulative control energy, for four types of response control systems are calculated by solving the moment equations, and the calculated results are compared.

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Active microvibration control systems are becoming necessary in high-technology fields, such as semiconductor manufacturing and microgravity experiments in space, to provide superior control performance to passive systems. In this study, an active system using a giant magnetostrictive actuator was tested using test apparatus designed for one-dimensional horizontal vibration control. The actuator consisted of a giant magnetostrictive rod with a 50 mm length and a 6 mm diameter surrounded by a driving coil. A control law was adopted, which could allow almost the same performance as sky-hook systems by feedback of only absolute acceleration of the isolation table. Vibration control experiments were carried out with satisfactory results in isolation performance against micro-floor motion, damping performance against direct disturbance and robustness of the control system.

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This study is concerned with basic characteristics and control performance of a bang-bang actuator. The bang-bang actuator studied here is a proof-mass type which is controlled by on-off command. The major advantage is that it can be made to be light in weight and low in energy consumption. Moreover, it does not require a servo-amplifier for each actuator and the number of actuators can be made large, so that it is suitable for distributed control. The analysis model is a flexible beam on which one or more bang-bang actuators is placed. It has been confirmed that the performance is approximately twice as effective as that of a tuned passive damper and nearly equal to that of a proof mass actuator under direct velocity feedback control. Moreover, it has been shown that vibration suppression by bang-bang actuators has definite advantages in energy consumption and robustness over conventional methods.

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The damping effects of an impact damper for the vibration neutralizer of pillar bodies are studied. The structure consisting of a beam, which is model of a pillar body, and an auxiliary mass coupled to the beam by means of a spring dashpot, which is a model of an impact damper, is considered. There is the gap between the beam and the auxiliary mass, and they collide with each other at one point when the system vibrates. The impact force is formulated by using Hertz's contact theory and the normal-mode approach is employed in the simulation. The validity of the simulation for free and random forced vibrations is examined by comparison with the experimental results. The effects of mass ratio, natural frequency ratio, gap size and impact point for free and random forced vibrations are discussed by simulation.

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In this study, it was aim to develop composite materials having both high-mechanical properties and high-damping properties. Due to improving both properties, we fabricated matrix hybrid composites. It was clear that matrix hybrid composites were distinguished materials depending on properties of matrix from that of reinforcement. Prediction of loss factors for these hybrid composites was attempted by superposition of sine waves. We investigated predicted values in comparison with experimental values.

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Impulse response has been studied in the spring-mass system in which silicone gel was incorporated. The dynamic characteristics of silicone gel were investigated experimientally. The results indicated that the coefficient of viscous damping and the stiffness varied with frequency and compression ratios. The silicone gel with established characteristics was installed to a spring-mass system. From the experiments under various compression ratios of the silicone gel, the impulse responses of this system were obtained. The results indicated that the responses decrease rapidly, compared with a conventional spring-mass system and differ in the compression ratios of the silicone gel. The impulse responses were calculated using the dynamic characteristics obtained experimentally. The calculated response waves and those obtained experimentally were similar in magnitude and decay.

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This paper presents a semi-active dynamic absorber for controlling the vibration of a beam subjected to moving loads. The eigenvalues of the beam system containing moving loads vary according to position and number of loads on the beam. The eigenvalues of the semi-active dynamic absorber are also adjusted to those of the beam system. The proposed semi-active dynamic absorber is of cantilever type and the absorber mass is moved to adjust the eigenvalues. It is difficult to estimate the characteristics of the beam system, which depend on the moving loads. The fuzzy control theory has robustness for uncertain systems. Therefore, the movement of the absorber mass is determined by fuzzy inference. In this paper, the adjustment of absorber mass to the position, which is determined by the displacement responses of the beam, is performed by the fuzzy controller. It is important to decide the control rules in the fuzzy control algorithm. The rule table is produced by the simulation of analytical models. The dynamic responses and spectra of displacements at the mid-point of the beam are shown in various cases. The effectiveness of the semi-active dynamic absorber is demonstrated experimentally.

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An approach for active noise control using structural vibration was proposed. No acoustic instruments such as loud speakers and microphones are necessary in this approach. The adaptive FIR filter using the LMS algorithm was used in the control system. Both a computer simulation and an experiment were carried out. The importance of using a howling canceler with the adaptive FIR filter was shown by the simulation. In the experiment, the vibration of the sidewalls of the duct was used for control. Good results were acquired using the simple controller.

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The finite-element method (FEM) is often used for acoustic field analysis in closed spaces. It enables users to solve complex acoustic problems in which acoustic fields of inner spaces are coupled with surrounding structures. In simple-shaped structures, however, the acoustic modal analysis method is more suitable than FEM from the standpoints of simplicity and interpretation of the results. The authors applied this method to the noise problem in a magnetic resonance imaging system (MRI). The MRI has been used for medical diagnostics in recent years. Structural design for noise reduction in the MRI is desired as considerable noise is generated in operation. This paper describes the modeling method of structure-acoustic coupled system of MRI. Theoretical predictions were compared with experimental results, and good agreement was obtained up to the frequencies in which the modeling condition was satisfied.

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An experiment was performed to study the movement characteristics of a shield tunneling machine of articulate type. Furthermore, operation data of practical machine were analyzed. As a result, effects of various factors such as articulation angle, overcutting range and soil characteristics on the rotation movement of the machine were clarified.

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Several studies were conducted to examine the movement characteristics of a shield tunneling machine of the articulate type. The authors extended mathematical models derived from the previous study to the articulate-type machine, performing an experiment and analyzing operation data at tunneling sites. Furthermore, the control system of the machine was developed based on the model and parameters of the system were optimized.

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This paper proposes a method that improves control performance in feedback control systems by introducing a multiple eigenvalue filter which has been deduced from parallel learning models. First, the controlled system model is copied to i (i=1, 2, …, k) systems corresponding to learning times. The actuating signal of the first model is added to the actuating signal of the second model, and then the actuating signal of the second model is added to the actuating signal of the third model. Likewise, the actuating signal of the k-1-th model is added to the actuating signal of the k-th model. Thus obtained k-th models are equivalent to the system which has a filter as a series compensator composed of the sum of i (i=0, 1, 2, …, k-1) multiple of the left side of the characteristic equation. In this paper, the sum is called a "multiple eigenvalue filter" and it is concluded that the filter is effective to eliminate control variable deviation without losing stability when disturbance is imposed.

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This paper deals with the eigenvalue problem of the multiple eigenvalue filter which was proposed in the previous paper, "Parallel Learning in Control Systems (Derivation of Multiple Eigen value Filter)". The system with proposed filter derived by means of parallel learning not only reduces control variable deviation without decreasing stability, but also has PID (Proportional, Integral and Derivative) control action although the original control system before learning has just proportional control action. In this paper, the reason is shown from the view point of eigenvalue problem and Nyquist stability theory.

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This paper deals with the problems of model output following control based on output feedback for the multi-input multi-output systems with additive and/or multiplicative unmodelled dynamics. Existence of an allowable range of unmodelled dynamics, which guarantees the uniform boundedness of all signals in closed-loop with output feedback, is examined for the system of which dominant part satisfies the almost strictly positive real (ASPR) condition. Furthermore, it is verified that the ASPR condition with respect to the dominant part can be relaxed using a precompensator inserted in the feedback path.

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This paper deals with the flexible rotor-mangetic bearing system (FR-MBS) which has three concentrated masses. A mathematical model of the flexible rotor in the case of free-free condition is derived using a finite-element method. The reduced-order model is derived for control system design by eliminating higher-order modes. Three kinds of reduced-order observers have been designed in this paper. We have confirmed that the VSS reduced-order observers have greater robustness to parameter variations in the system. The sliding mode controller for this reduced-order model is proposed using sliding mode control theory, and the simulations are done on the calculating model in the two cases of the lift-off and rotations. The two unstable rigid modes can be easily controlled with good stability and the spillover phenomena caused by the higher-order modes do not occur. Moreover it is clear that the sliding mode control design is robust with respect to model parameter variations and external disturbances.

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A new method for final-state control by feedforward input is presented and a simple algorithm to obtain the input is given. It is shown that for closed-loop systems with feedback compensators, a reference input can be used as the feedforward input for final-state control. The proposed method is examined through positioning control of a cart and flexible pendulum system. In order to suppress the vibration of the flexible pendulum, a minimum real H^∞ controller is designed, and feedforward input for the final-state control of this closed-loop system is derived and tested through numerical calculations and experiments. As a result, it is shown that the performance of final-state control and vibration suppression by the feedforward input designed for the closed-loop system is superior to that designed for the open-loop system without a feedback compensator.

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This paper proposes a new method to improve the handling and stability of vehicles by controlling the yaw moment generated by driving/braking forces. Yaw moment is controlled by the feedforward compensation of steering angle (and steering velocity) to minimize the side slip angle at the vehicle center of gravity. To realize this kind of yaw moment control, the right and left driving/braking forces should be controlled independently. Theoretical analysis and computer simulation are carried out to show the effectiveness of this control system. The results show that the handling and stability are improved significantly compared to those of the conventional two-wheel-steering vehicles, and that a 4WS-equivalent vehicle performance is obtained. This control effectiveness is also verified by experimental results using a downsized vehicle model on a moving belt tester.

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A new active control method for the attitude angles of wheels is proposed to improve the maneuverability and stability of vehicles. It is expected that a system for controlling not only the steer angles of the front and rear wheels but also their camber angles will make it possible to provide enhanced vehicle dynamics mainly due to the effect of camber thrust force, particularly such as under cornering behavior with relatively large lateral acceleration. According to theoretical analysis and computer simulation, it can be confirmed that the attitude control system of tire-wheels which uses combined methods of feedforward and feedback controls corresponding to various running conditions can realize the intended vehicle response characteristics in wider maneuvering ranges of lateral acceleration than four-wheel-steering systems depending on steer angle control only.

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The operation training simulator for refuse incineration plants was developed, which can be used for the training of the plant start/stop operations or restoring operation from unusual situations. The system was introduced to SENOKO plant in Singapore for the first time. The system consists of DCS(distributed control system) which has the same specifications as the one actually being used, and the mini-computer used for the process simulation. Trainees can practice in an operating environment which is the same as that in a center control room of the actual plant. The process model covers the major machines of the furnace, turbine and common equipment, and the trainer can easily vary the plant conditions. This report describes the outline of the system structure, that of the training course, the training scenario of the restoring operation and examples of the training results.

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In this paper, the magnetic levitation neuro-adaptive control method of a body by use of an electromagnet attached to a vertical robot with a prismatic joint is presented, and the usefulness of the present control method is confirmed by experiment and numerical simulation. When the gap between the levitated body and the electromagnet hand varies, an adaptive control method to compensate the nonlinear characteristics of the magnetic attracting force is desirable. The magnetic levitation neuro-adaptive control system consists of a PD feedback control loop and an adaptive mechanism based on a neural network. From the experimental results and the numerical simulation results, it is confirmed that the levitated body can be controlled successfully by the present magnetic levitation neuro-adaptive control method.

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In this paper, a new method is proposed to analyze the behavior of a cam with arc, straight and corner contours. This method is characterized by converting cam behavior into linkage behavior, that is, a cam is modeled by linkage. This method can give for the cam and linkage parts of a compound mechanism simultaneously using conventional linkage analysis. The method is successfully applied to a computer aided analysis of the dynamic behavior of compound mechanism with a cam and linkages in an automatic teller machine. Furthermore, the accuracy of calculation of the mechanism's dynamic behavior is discussed for two analytical models, the series model and the parallel model.

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An active lead screw mechanism (ALSM) has been proposed as an ultraprecision positioning mechanism at a high speed. The ALSM is able not only to control backlash between a screw and a nut but also to position a table by piezoelectric actuators. In order to realize this ability, the ALSM must have access to a set of backlash data or be capable of real-time measurement of the backlash. In the first report, the backlash was measured beforehand as a function of the rotation angle of the lead screw, which required a tremendous amount of labor. First this report describes the real-time measurement and the elimination of the backlash. The frictional force between the screw and the nut depends on the backlash. In this paper, the backlash is measured using the change of frictional force. Then the positioning controller is improved to reduce the positioning time. In order to reduce the overshoot, the coarse-positioning controller (P-D) changes the proportional gain according to the deviation. In order to quickly reduce the residual vibration caused by coarse-positioning, the parameters of the fine-positioning controller (PI-D) were changed.

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A new flying height tester has been developed for magnetic head sliders. This tester measures the light interference fringe patterns between the slider and a glass disk, and calculates the absolute flying height from their peak positions. The tester uses monochromatic incoherent UV and visible light, which has a minimum wavelength of about 200 nm, and the slider's dynamic motion measurement system is separated from the static flying height measurement system. Hence, it can measure a 50 nm flying height within an error of less than 1 nm. The tester can also measure a slider's dynamic motion in the 0-100 kHz frequency range using photodiode arrays. The performance of the tester was confirmed through careful experiments.

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This paper presents a scheme to obtain large output power from a hydraulic reciprocating pump in which the diaphragm is driven by a multilayer piezoelectric element (MLPE). The scheme is summarized as follows : (i) reduction of the spring constant of the diaphragm for elongation of the MLPE, (ii) application of static pressure on the working liquid in the hydraulic circuit, and (iii) connection of pumping valves and pressure chambers with pipes having the same resonant frequency. When the MLPE is driven at a frequency near the resonant frequency of the pipes, the pressure behind the exhaust valve fluctuates violently such that it decreases at the exhaust stroke. Similarly, the pressure in front of the intake valve increases at the intake stroke. Then, due to the elasticity of the MLPE, the flow rate of the pump increases considerably compared with the case of no resonance. To illustrate the effectiveness of the scheme, it was applied to improve the performance of a pump (max. power 34 W, efficiency 27%) which was driven by the MLPE of 22 mm diameter, 55.5 mm length and 170 g mass. Consequently, its maximum power and efficiency were increased to 62 W and 35%, respectively. Since the efficiency of the valves was only 51% in this experiment, further improvement should be achieved in the future by using better valves.

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At construction sites, it is essential that robots move in all directions, because the worksite is very expansive. A robot must move functionally under conditions where floor surfaces are not flat and have many different levels and obstacles. In this paper, we deal with an omnidirectional walking vehicle which can move in all directions and has a simple structure. The walking mechanism proposed in this paper consists of a parallel link mechanism connecting the two frames with three linear actuators. Each frame has extendable legs, and this walking vehicle can walk on a rough floor. The relative position and rotational angle of the two frames can be controlled in accordance with the length of the three linear actuators. We also solved the inverse dynamics of this vehicle. The simulation results show effectiveness of the proposed control method.

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We design a machine which adapts to the user considering personal differences. This paper deals with the interactive relationship in which both the user and the machine try to adapt to each other. We call this relationship interactive adaptation. The interactive adaptive interface (IAI/F) is an intelligent interface which is designed in consideration of interactive adaptation. This interface changes the characteristics of the system according to the given task, taking into consideration the state of the user, such as skill level, technique, characteristics, physical conditions. We propose a design and realization method for the IAI/F, based on recursive fuzzy reasoning. As an application example, we present a virtural-reality simulation game and apply the proposed IAI/F based on the user's performance and the skin potential reflex (G.S.R.). We present the system considering interactive adaptation, and show some experimental results and statistical evaluation results to discuss its effectiveness.

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This paper deals with the improvement of learning speed based on the analysis of convergence of the feedback error learning method. We derive and obtain the condition for the asymptotic convergence of the feedback error learning method for each trial. This condition is the relationship between the learning rate and the α function, which is calculated from the input-output relationship of the system. Using the α function, we propose a high-speed learning method for a tracking control system. We present the simulation results for the tracking control system of a one-link robot manipulator for two cases as follows : (1) use of the general feedback error learning method and (2) use of the proposed high-speed learning method. The simulation results show the effectiveness of the proposed conditions and learning method.

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This paper deals with the Micro Optical Robotic System (MORS) with cordless optical power supply system. The MORS is the robotic system, which utilizes the concept of the Micro Cellular Robotic System (μ-CEBOT). The purposes of developing the MORS are to develop the prototype of μ-CEBOT and to solve the problems such as the friction and the power supply which hinder the development of the micro electro mechanical systems. The MORS consists of a floating robot and an air table : the former is driven by the cordless optical power supply system, and the latter works as the air bearing. The optical power supply system converts from the optical energy to electrical energy using the pyroelectric element. The optical power supply system generates the electric voltage, and the electric voltage generates the electrostatic force between the electrodes of the robot and the blocks of the air table, which work as the electrodes. The electrostatic force generated drives the robot above the table. In this paper, we propose the design of the MORS, and show the mathematical model of MORS and the some experimental results.

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This paper deals with the development of a new method of detecting the number of moving sheets without contact. For example in a cash dispenser, paper sheets are transferred one by one and counted synchronously. Thus it is necessary to detect one or a many sheets to avoid mistransfer. Hitherto, the contact measuring method for detecting the transference of sheets has been used. Our noncontact sensor utilizes the variations in frequency response of the entire acoustic system of the sensor including the moving sheets. The impedance of sheets varies with its number. Thus the number of sheets shows good correspondence with the resonant frequency and frequency response of the acoustic system. It is possible to detect the number of moving sheets during a very short time period by means of variations in the frequency response.

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A sensory substitute for blind people on the basis of acoustic transmission has been developed and practical tests have been carried out. The characteristic of the method is that the apparatus uses stereoscopic audible signal transmission so that blind people can detect scenery images more clearly. Wide-scope distances are detected with use of a camera and a slit-type laser under the principle of triangulation. Distance signals in eight directions are transformed into variable frequency signals corresponding to the actual distances and are simultaneously transmitted to a person through a headphone set as stereoscopic audible signals. This function made it possible for a user to recognize the simple scene of objects which lie in front of him and to walk between the obstacles. As a result of the practical test, it became evident that the percentage of valid answers in recognizing the object shape was high and the walking stability was improved with training. It is confirmed that the apparatus can be used as a vision substitute.

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This paper describes a new theoretical approach to formulate the non-Newtonian turbulent lubrication theory based on the friction law of fluid. Combining the concept of equivalent pressure flow and resistance formula for pressure flow in the lubrication films, the one-dimensional generalized turbulent lubrication equation considering the non-Newtonian effect of lubrication fluid is derived, in which the equation for non-Newtonian turbulence coefficient is greatly simplified under the assumption of strong shear flow. The non-Newtonian turbulent lubrication equation obtained is applied to the inclined long slider bearing, and the bearing performance such as pressure distribution, load capacity and friction force is analyzed. From the results, the effect of non-Newtonian characteristics on the turbulent lubrication behaviour of long slider bearing is clarified.

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The influence of materials and contact geometry of rollers on traction curve is studied for the purpose of achieving high function and light weight in traction drive. Two traction oils, Santorac50 and Daphne7074, are used, and steel, zirconia and silicon nitride are used as the materials of rollers. The elastic shear moduli of two lubricants are presented. The contact geometry of rollers does not greatly influence the traction curve, while their elastic modulus and thermal conductivity consider-ably influence the initial slope and the maximum traction coefficient of the traction curve, respectively.

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The problem of calculated and measured values of plain journal bearing oil film coefficient not giving the same reading in the region of high eccentricity ratio has been addressed through various approaches (e.g., THD analysis) in an effort to determine the cause of such a discrepancy, all to little avail. The authors studied the relation between the bearing oil film dynamic characteristics and the boundary condition for the region of oil film pressure generation and, by assuming that the squeeze oil film forms only when the rotor shaft journal approaches the bearing metal, the damping coefficient more closely approximating the experimental value than hitherto could be calculated.

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This study is on tribology for smal two stroke cycle spark ignition engines fueled by M85(gasoline 15% + methanol 85%) and M0 (gasoline 100%). Separation occurs when lubrication oil is added to the gasoline-methanol blended fuel. Therefore, lubrication oil is supplied to the intake manifold separately from the fuels, and the oil-to-fuel ratio is about 1 : 30 for M0 and 1 : 60 for M85. Wear data for M85 under constant speed and WOT (wide-open throttle), is compared with data of a M0 counterpart. The sludge formed during engine operation was found to affect the cylinder wear performance.

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For the use of submerged bearings in vertical pumps, a considerable quantity of dry-start bearings come to be used, adapting polytetrafluoroethylene (PTFE) or ceramics (SiC) as the sliding component and synthetic rubber (NBR) as the cushion. However, pumps equipped with these bearings sometimes give rise to problems related to wear of bearings or vibration of pumps chiefly from the lack of data on these new bearings. Therefore focusing on the grooves on the sliding surface of the bearings, a fundamental test was performed using the test pieces, and it was clarified that the grooves decrease the apparent elasticity and the stress of the sliding surface of the bearings.

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Double-ply-welded bellows of nesting type are used as sealing devices of valves for high-temperature and high-pressure applications, and so far, the same-metal-welded bellows have been used exclusively. In the present investigation, the authors manufactured dissimilar-metal-welded bellows aiming at high corrosion resistance as well as mechanical strength. Namely, highly corrosion-resistant Ni base alloy B is placed on the fluid-contact side and higher-strength Ni base alloy A is placed on the no-fluid-contact side for the purpose of mechanical back-up of Ni base alloy B. As a result of study on its characteristics, it has been found that the welded part of this dissimilar-metal-welded bellows has mechanical strength near that of the Ni base alloy A and the chemical composition is intermediate between Ni base alloys A and B. Furthermore, it was confirmed that this bellows has higher resistance to corrosion than the bellows made of only Ni base alloy A, and has a longer total life than the same-metal-welded bellows made of only Ni base alloy A or B.

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Planar cams are typically machined by NC machine tools using linear and circular interpolation functions. This causes polygon-shaped cams which sometimes are not acceptable for industrial use due to the large vibration of cam follower members. There are no general guidelines to define the control point of the polygon to obtain reasonable error between the polygon and the theoretical contour of the cam. First, the error defined by the linear interpolation on Cartesian and polar coordinates is introduced for the guiedlines. Then, two novel methods are established to define the contour of cams. One gives equal error over the entire contour of the cam. The other equally divides the contour with acceptable error. The result of the simulation using four different types of planar cam mechanism shows the advantages of these methods, such as the smaller number of necessary data than in the conventional techniques.

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In general, in finishing helical gears with modified tooth traces, it is necessary to consider an additional motion between the work and tool in the manufacturing process. In this paper, shapes of tooth surfaces of gears ground with the threaded wheel or profiled wheel with three kinds of additional motions between the work and wheel are shown by means of contour lines, and it is clarified that form grinding with the profiled wheel is the most suitable for finishing gears with three-dimensionally modified tooth surfaces. Moreover, a method of calculating amounts of the additional motions for 3-D tooth-surface modification when the approaching and excessive helical motions are used as a combination of the additional motions in form grinding is proposed. To demonstrate the usefulness of this method, the grinding tests of the helical gears were conducted on the CNC gear grinder. The shapes of the ground tooth surfaces were almost the same as those of modified ones in the design stage.

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In order to automatically calculate the stress distribution of a spur gear tooth on the personal computer, a stress analysis system was developed. This system has four main functions : (1) gear cutting tool design, (2) gear tooth generation, (3) determination of the coordinates of tooth profile and the mesh pattern, and (4) use of a finite-element method for stress analysis and determination of calculated values. It is easy to design a rack cutter by the use of a simple CAD devised by the authors. The tooth profile generated using this cutter can be confirmed on the personal computer. The determination of the coordinates of tooth profile, the mesh pattern, and the boundary condition needed for the finite-element method is carried out automatically. Through an example, it is confirmed that this system is a useful tool for the design of the tooth profile which decreases maximum stress imposed on the fillet of spur gear.

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