As per ISO376 : 2011, creep uncertainty can be measured directly or indirectly. In this regard, this paper seeks to provide a comparison between direct and indirect creeps computed from hysteresis. All computations for direct and indirect creeps were done using equations from ISO376 : 2011. Five force measuring devices were experimentally examined for this purpose. Results showed that the behaviors of direct and indirect creeps were quite different. The relative creep that was directly measured was constant. On the other hand, the relative creep that was indirectly estimated varied with the applying force. Therefore, the directly measured creep cannot be replaced by the indirect one. This paper proposes a method to use a representative value for indirect creep, as the maximum of the creep. For the force measuring devices that had good hysteresis characteristics, the directly and indirectly measured creeps were comparable. However, for the force measuring devices with poor hysteresis characteristics, the indirectly estimated creep was much higher than the directly measured creep. Therefore, it is highly recommended to measure the creep directly for the force measuring devices characterized by poor hysteresis.

Defects in the insulator bushing are the major caution of destroying a switchgear. An epoxy bushing is composed of epoxy-molded insulator layer and a conductor. That means, a porosity or delamination defect could be included in the insulating layer by the manufacturing process. An inspection method is required to secure integrity of the bushing. An ultrasonic-immersion system has the power to produce a required effect to examine critically an epoxy material with high degree of fineness. In this research, an optimized ultrasonic immersion system was developed and applied to examine critically the epoxy-layer of bushings. As results of the result of a careful examination, both artificial defects and delamination were detected by the system. Currently, the ultrasonic-immersion system should be applied for examining the epoxy-layer of the bushing carefully.

A separator used by marine engine functions as a purifier by dividing engine oil into pure oil and impurities. By rotating the separator at a high speed between 1800 to 4500 rpm, fine particles of oil inside the separator are centrifuged due to the weight difference when the engine oil is refined. The impurities, so-called sludge, should be manually removed by taking the separator apart from the oil purifier system unless the accumulated sludge is measured and monitored in real time. A manual discharge of the sludge causes an increase of cycle time to clean the engine oil as well as operator exposure of safety risks. Therefore, the development of automatic system with a sludge monitor and an actuator is necessary for ship engine efficiency. In this paper, the pressure difference from the accumulated sludge is monitored via a pressure sensor. By measuring the pressure exerted at the wall surface, the amount of sludge was quantitatively estimated within the error of 0.032-0.091 kg when the oil purifier system has been automated.

This paper proposes a review of the robot’s vision control scheme using the data moving method, to improve the accuracy and processing speed for the tracking of a moving target. The vision system model, which can actively adjust the camera parameters for the camera and robot position changes is used for this study. The method of processing the vision data obtained during robot movement toward the target can be classified into a batch method using all the acquired data, and a data moving method using only limited data. In an effort to reduce the number of vision data obtained while the robot moves toward the target, the proposed control scheme estimates the optimal number of robot moving points near the target, to exclude the old data and use only the limited data obtained near the target recently. In this study, limited data are utilized. In order to show the effectiveness of the proposed control scheme, we set the control method based on the batch processing method, and then compared these two results with the accuracy and the processing time by performing the experiments of the slender-bar moving target tracking method.

Steam turbines of thermal power plants are installed in such a way that packing ring surrounds the entire turbine rotors in order to reduce the amount lost due to a leak of steam and to improve performance. However, the conventional packing ring cannot affect positively fluid velocity of the direction of steam, so it does not have the power to reduce vibration of the rotor. In this research, a study was conducted to reduce it by lowering the rotational speed of steam in the rotor. Anti-swirl teeth which changes rotational speed of steam into axial speed of it, designed in front of the conventional packing rings, and their numbers, twist angles. The characteristics of the rotor and the anti-swirl teeth were chosen as design factors to reduce vibration of the rotor. Through the finite element, the improved packing ring designed with the optimal anti-swirl teeth was developed.

Recently, the concern for safety is increasing as customers’ interest in Run-Flat tires, which can assure their safety in case of a puncture when driving, is growing. Run-Flat tires continues to evolve with the demands of customers who want the performance of general tires such as fuel-consumption and comfort from the basic Run-Flat function in the 1st generation. Run-flat tires are designed in various ways to cope with puncture in pneumatic tires. Currently, Run-flat tires in which Runflat Inserts are inserted into sidewalls of the tires are mainly used. In this study, we would like to propose a method to predict the temperature of sidewall of a Run-flat tires while running and how it affects the durability. We predicted the temperature distribution of sidewall during the running of Run-flat tires by calculating energy loss which is from the viscoelastic characteristic of rubber through deformation analysis of tires, and verified the prediction technique by comparing with the Run-flat endurance test.

This study reviews the assumption that the lightweight design of commercial vehicles is significant from the aspect of the anticipated fuel consumption and environmental regulations that are consequently applicable to those vehicles. Generally speaking, it is noted that among the numerous trailer components, a stub axle, which is designed to independently operate as an integral part of trailer’s suspension, can play an important role in increasing the shipping capacity of a box trailer. For this reason, because each stub axle is comparatively a heavy unit in itself, and a total of six stub axles are mounted in a box trailer, the lightweight design of a stub-axle is noted as an essential factor to reduce the whole weight of a trailer. For a finite element analysis, an original CAD model is modified through removing a chamber, airbag, axle drum, bearing and pivot on a vehicle. In addition, the loading conditions are imposed considering three extreme driving conditions and the effects are studied when in the event of review of a fully loaded in a box trailer. A topology optimization is conducted to determine a lightweight design for minimizing compliance under these boundary conditions.

In this work, the degradation progression of a polyurethane (PU) hydraulic reciprocating seal with respect to the sliding distance were investigated using a pin-on-reciprocating tribo-tester. Also, the acceleration effect of alumina particles added in lubricant on degradation of PU seal were assessed, with an aim to contribute to the development of accelerated wear testing methods. As a result, It was shown that the height of PU specimens decreased drastically at the initial stage of sliding. Then, the height decrease was found to become gradual as sliding distance further increased. The result also shows that the height decrease of the PU specimen was mainly due to the effect of the compression set and wear. In addition, the noted abrasive wear of the PU specimens was found to be significantly accelerated due to the alumina particles in lubricant, which determined a further result in 50 % faster height decrease with increasing sliding distance, as compared to the normal lubricant. The outcome of this work may provide significant and useful information for the prediction of the lifetime of a hydraulic reciprocating seal, and for the continued development of accelerated wear testing of the hydraulic reciprocating seal.

Recently the application of high strength steel sheets, such as DP, TRIP, and TWIP, is rapidly increasing in the automotive industry. Despite this trend, springback is still one of major obstacles that has yet to be overcome. In this study, we conducted U-draw bending experiments and analyzed the process with FEM, focusing on the springback. In the FE analysis, the effects of the hardening model ware studied by comparing the results among an isotropic hardening model, a combined isotropic-kinematic hardening model and the experiment. The effects of the restriking process on shape correction was also =studied by comparing the results of the springback analysis and the experiment.

The liner of CNG pressure vessel was manufactured using a deep drawing and ironing (D.D.I.) process with a single punch. Tip clearance between billet and die suggested in the actual field has been widely used to reduce forming load and to improve die life. However, the analysis and design of tip clearance is necessary for the third stage of forming defect. In this study, the tip clearance of the third stage was determined to limit the ratio of reduction of cross-sectional area based on theoretical analysis. The proposed tip clearance was verified via finite element analysis. In addition, the simulation technique was established by comparing the forming load based on theoretical calculation with the load determined via FEM.

The incidence of adjacent segment degeneration (ASD) after lumbar spinal fusion have not been precisely verified. In the presence of mild degeneration in the proximal segment adjacent to the fused segment, selection of additional fusion is not agreed upon. Muscle activity change and ASD after fusion was analyzed with a developed three-dimensional finite element model of musculoskeletal system. The paraspinal muscle activities were calculated based on a hypothesis, the intervertebral disc was assumed to have a transducer function and the muscle is activated according to a sensor driven control mechanism to maintain the stability of the lumbar spine. Simulation was conducted for erect standing and 60° isometric forward flexed posture. Total muscle force produced in each deep muscle group was similar however activity of some muscle fascicles which inter-connected to the vertebrae above the fused segment showed increased value. In the presence of mild degeneration in the proximal adjacent segment, muscle activity across the degenerated segment was reduced. Despite changes in muscle activity, nucleus pressure at adjacent segment was increased in both cases. This change would eventually lead to the ASD.

Generally speaking, the high speed forming process is suitable for the precise manufacturing of hard-to-form and high strength materials. This study conducted microscale embossing and punching experiments by establishing a forming system that uses a laser induced acceleration. The changes in the flyer velocity with the laser energy, flyer thickness, and flyer diameter were measured using a high speed camera, and the effects of the noted acceleration characteristics of flyers on processing performance were investigated. It is particularly important that in the case of punching, the advantages of high speed processing, in which the accuracy was improved by increasing the shear zone of the workpiece, were identified. Significantly in the case of embossing, it was observed that the formability improved by increasing the flyer velocity as the flyer diameter decreased. However, in the case when the flyer thickness was decreased, increased energy was consumed in the plastic deformation of the flyer, and the advantages of high speed forming could not be realized. For this reason, further research is needed to take advantage and optimize the forming process using the laser induced acceleration through experiments which are noted as considering the various process variables and materials.