The crack initiation equals to fracture for bonded joint with brittle adhesive. The criterion is formulated in terms of the quasi-stress intensity factor Kp, for the maximum principle stress, that is analogous to the stress intensity factor used to characterize the stress field in the vicinity of bond terminus. Kp is evaluated using a boundary element analysis. The crack initiation at the terminus of adhesive bonded joints is estimated with the critical quasi-stress intensity factor Kp. This method presented here hardly pays attention to the crack propagation. Since there is a large influence of crack propagation on the strength of adhesive joints and structures, crack propagation must be taken into account on strength prediction of bonded joints. The quasi-stress intensity factor Kp for the maximum principle stress can use as the criteria of the crack initiation at the terminus of adhesive bonded joints having various shapes.
This paper presents a study of the influence of cutting parameters on surface finish obtained by face milling. Cutting conditions have significantly great effect on surface quality in high-precision machining. Fundamentally, surface roughness are strongly correlated with cutting parameters such as feed rate, cutting speed and depth of cut. Optimal selection of the cutting parameters can obtain better surface roughness. Therefore, optimization of the cutting parameters in a face milling based on the parameter design of the Taguchi method is adopted in this paper to improve surface roughness. And optimal cutting parameters based on the results of the S/N ratio and ANOVA analyses to performance high-precision machining is obtained and verified by confirmation test.
The Consultation about Energy Use Plan is prescribed by the Rational Energy Utilization Act. This paper proposes a regression model for estimating consultation objects each year. Analysis results predict for the next six years that the mean annual energy saving effect is 13.2%, mean annual CO2 reduction effect is 13.4% and benefit-cost ratio is 2.48, it means economic and social future effect with the Consultation about Energy Use Plan are very excellent. Also the effect of introducing system improving efficiency of energy use is expected to account for 62%, recovering waste heat account for 17%, introducing group energy supply account for 18% and utilizing new․renewable energy system account for nearly 3% of total energy savings on plan for improving efficiency.
The vibration control of a flexible rotor supported on cavitated short squeeze film dampers is investigated. According to Pan's theory, the shape of cavitation in fluid film bearings depends on the level of oil supply pressure, as a result, both the direct and the cross coupled damping coefficients of a cavitated short squeeze film damper are varied widely. In this paper, controling the level of oil supply pressure by fuzzy theory, a significant reduction in journal eccentricity ratio, rotor amplitude and force transmissiblilty of a flexible rotor system is achieved.
Recently, the Ranque-Hilsch vortex tube is widely used for the local cooler of industrial equipment for special purpose. Although many studies on energy extraction in the vortex tube using air as the working fluid have been made so far, a few experimental studies treated solid particles extraction for incompressible fluid. So, an experimental study for the solid particles extraction in the vortex tube(Ranque-Hilsch vortex tube) using the water which is essentially an incompressible fluid is presented. The experiments were carried out with various cold end orifice diameter ratios ranging from 0.25 to 0.70, the input pressure ranging from 1 to 3MPa was considered. The emphasis was given to examine the effect of geometry factors of vortex tube at working fluid(water) for solid particles(Al2O3) extraction. The optimum geometry factor and inlet pressure for the maximum solid particles extraction was found that the smaller cold end orifice diameter ratio and the higher inlet pressure in experimental condition increase.
Numerical solutions are presented for compressible fluid flow past a rotating elliptic cylinder in a medium at rest at infinity. Flowfields and acoustic waves emitted from rotating elliptic cylinder are directly simulated by the Lattice boltzmann method formulated by the Arbitrary lagrangian eulerian scheme. The flowfield is almost periodic after the calculation fully developed and studied by means of streamlines and equi-vorticity lines and by means of drag, lift and moment coefficients. The positive and negative vorticity is alternately occurred at the edge by those large vortexes. The acoustic waves propagate synchronizing with the rotation and increase with M3.5 of rotational speed of elliptic cylinder.
In this paper, the situation of energy efficiency standards and MEPS (Minimum Energy Performance Standard) for motors and diffusion states are analyzed. For this purpose, a new methodology is used, which was proposed in the existing study, using diffusion models and learning curves. The existing diffusion models could not explain affects from new appliances' penetration during the diffusion. But a mixed diffusion model with learning curves or learning ratio is studied to explain this penetration.
Kart-Racing which is called a microcosm of F1`s racing is the most basic step in the car racing. A Kart consisting of the very fundamental structure which does not include differential gear and suspension is sampler than a typical car. It is necessary to reduce the Lab time at the Kart-racing`s corner so the research investigate the Kart through check of racing condition and of driving factors about cornering. The study measured to make the kart closely factual condition which was showed the main parameters for more actual decision of kart`s dynamic characteristics and estimated the real-time data from the developed kart whose sensor was installed at all tires and which was pursued through the GPS.
Gas welding is a very important and useful technology in the fabrication of railroad cars and commercial vehicle structures. However, since the fatigue strength of gas-welded joints is considerably lower than that of the parent material due to stress concentration at the weld, the fatigue-strength assessment of gas-welded joints is very important for the reliability and durability of railroad cars and the establishment of a criterion for long-life fatigue design. In this paper, in order to save time and cost for the fatigue design, an accelerated life-prediction method that is based on the theory of statistical reliability was investigated. Its usefulness was verified by comparing the (Δσa)R-Nf relationship that was obtained from actual fatigue test results with the (Δσa)R-(Nf)ALP relationship that was derived from accelerated life testing. And the reliability of the predicted life was evaluated. The reliability of the accelerated life-prediction on the base of actual test data was analyzed to be (81～86)% of the actual test life of the fillet-type gas welded joint.
This study is concerned about the robot joint mechanism with the slider joint. Most of robots are sliding using rolling bearing, cam follower or roller follower in the slider joint. Because such structure must impose pre-load so that outer ring of the bearing may have suitable contact force on contact side, when used many long term, life is fallen, and become factor of rising prices because must do precise machining about parts that use. This research proposes method to solve such problem. This research applies method to use sliding bearing instead of rolling bearing and develope mechanism that can operate for this. Also, this research develops structure that can transmit power using gear to reduce cost price. And optimal design for gear and main parts is achieved.
In order to supply the high-quality electric power, several researches have been conducted. For the high-quality power, it is necessary to inspect the power lines and insulators before the lines or insulators are disconnected or damaged. However, it is not enough to inspect all the power lines by human inspectors. In previous study, a power line inspection robot was developed to investigate the power lines and insulators. According to replace the human operators by the robot, the inspection robot has several advantages: the improved working conditions, machine accuracy, and the prevention of accident. However, the robot has some defects in its heavyweight. In this study, a lightweight inspection robot has been developed using a RP and a vacuum casting. And, this study developed a fault detection monitoring program for the high voltage equipment using a microphone which detects the location of fault and the thermal imaging and CCD cameras which verifies the fault and stores the image, respectively.