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Numerical Study on the Inlet Head Configuration of Multi-Phase Separator for Modularization
Hong, Chang-Ki;Kim, Youn-Jea;
Transactions of the Korean Society of Mechanical Engineers B, vol. 41, iss. 9, 2017, pp. 571-577
In this numerical study, the separation efficiency of three-phase separator in an oil-sand plant was studied with various inlet head configurations. The free water knockout (FWKO) vessel was designed with a flow rate of
(100 bbl/day) and the SOR(stream-to-oil ratio)
Development of an Intelligent Legged Walking Rehabilitation Robot
Kim, Hyun;Kim, Jung-Yup;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 825-837
This paper describes a novel type of a walking rehabilitation robot that applies robot technologies to crutches used by patients with walking difficulties in the lower body. The primary features of the developed robot are divided into three parts. First, the developed robot is worn on the patient`s chest, as opposed to the conventional elbow crutch that is attached to the forearm; hence, it can effectively disperse the patient`s weight throughout the width of the chest, and eliminate the concentrated load at the elbow. Furthermore, it allows free arm motion during walking. Second, the developed robot can recognize the walking intention of the patient from the magnitude and direction of the ground reactive forces. This is done using three-axis force sensors attached to the feet of the robot. Third, the robot can perform a stair walking function, which can change vertical movement trajectories in order to step up and down a single stair according to the floor height. Consequently, we experimentally showed that the developed robot can effectively perform walking rehabilitation assistance by perceiving the walking intention of the patient. Moreover we quantitatively verified muscle power assistance by measuring the electromyography (EMG) signals of the muscles of the lower limb.
Fatigue Crack Growth Characteristics of Cold Stretched STS 304 Welded Joint
Lee, Jeong Won;Na, Seong Hyeon;Yoon, Dong Hyun;Kim, Jae Hoon;Kim, Young Kyun;Kim, Ki Dong;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 809-815
STS 304 steel is used as pressure vessel material, and although it exhibits excellent mechanical characteristics at a low temperature, it is heavier than other materials. To address this issue, a method using cold-stretching techniques for STS 304 can be applied. In this study, a cold-stretching part and welded joint specimen were directly obtained from a cold-stretching pressure vessel manufactured according to ASME code. Fatigue crack propagation tests were carried out at room temperature and
using the compliance method for stress ratios of 0.1 and 0.5. The results indicate that crack growth rate of the welded joint is higher than that of the cold-stretching part within the same stress intensity factor range. The outcome of this work is expected to serve as a basis for the development of a cold-stretched STS 304 pressure vessel.
Numerical Simulation of a Gun-launched Projectile Considering Rifled-gun Tube
Joo, Geunsu;Huh, Hoon;Jung, Yeong Hyuk;Kim, Ju Yeong;Seo, Songwon;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 877-885
This paper is concerned with numerical simulation of a gun-launched projectile considering a rifled gun-tube. Gun-launched conditions induce dynamic behaviors, such as high pressure and high speed rotation. A projectile and its internal electronic components may be damaged in such harsh environments. Hence, it is necessary to perform numerical simulation of a gun-launched projectile to predict its dynamic behaviors and stability. In this work, preceding research studies on gun-launched projectiles are investigated, and the simulation method is developed to rotate the projectile through between its rotating band and a rifled-gun tube. The proposed method is verified by comparison with experimental results, and the dynamic behaviors and stability of the projectile are evaluated under gun-launched conditions.
Design of Magnetic Field Generator based on Magnetic Shield Effect for Stiffness Control of Magnetor
Jang, Dae Ik;Park, Jae Eun;Kim, Young-Keun;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 861-868
In this study, a novel magnetic field generator, using a shielding effect for controlling the dynamic stiffness and damping of magnetorheological gels, is proposed. A magnetorheological gel is a smart material that can alter its stiffness and damping, and it can be used as a vibration absorber and in vehicle suspension. It is necessary to control the magnetic field to use magnetorheological gels in various applications. There are two types of magnet field generators, namely the electromagnet and permanent magnet, and the electromagnet is generally used in practical applications. However, owing to its limitations, the electromagnet is not suitable for long-term use. Therefore, in this paper, a novel magnetic field generator is proposed to address such problems for use in real applications.
Accelerated Life Test Design of an Electromagnetic Shielding Door Hinge
Kim, Do Sik;Cheong, Han Young;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 887-895
This paper presents a study on the accelerated life tests of parts that operate during the opening and closing of door frames, particularly door hinges. Hinge theoretical verification and validation of the test equipment in the present study and the different structures and fault mode, depending on the purpose of usage analysis, failure mode for one of the hinges of the switchgear components used for electromagnetic shielding facilities and on-site operating conditions. The accelerated life test was designed for the characteristic lifetime prediction of the components, by estimating the shape parameter and the acceleration factor.
Kriging Surrogate Model-based Design Optimization of Vehicle and Adaptive Cruise Control Parameters
Kim, Hansu;Song, Yuho;Lee, Seungha;Huh, Kunsoo;Lee, Tae Hee;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 817-823
In the past, research has been conducted on the development of an adaptive cruise control algorithm considering fuel efficiency, and an adaptive cruise control system considering fuel efficiency have been developed. However, research on optimizing vehicle and adaptive cruise control parameters in order to maximize performances is insufficient. In this study, the design optimization of vehicle and control parameters considering fuel efficiency, trackability, ride comfort and safe distance is performed. This paper proposes performance measures of vehicle behavior and develops an adaptive cruise control system. In addition, based on the screening of vehicle parameters that significantly influence performances, kriging surrogate models are constructed through a sequential design of experiment, and kriging surrogate model-based design optimization is performed to maximize fuel efficiency and satisfy target performances.
Pedestrian Walking Velocity Estimation based on Wearable Inertial Sensors and Lower-limb Kinematics
Kim, Myeong Kyu;Kim, Jong Kyeong;Lee, Donghun;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 799-807
In this paper, a new method is proposed for estimating pedestrians` walking velocity based on lower-limb kinematics and wearable inertial measurement unit (IMU) sensors. While the soles and ground are not in contact during the walking cycle, the walking velocity can be estimated by integrating the acceleration output of the inertial sensor mounted on the pelvis. To minimize the effects of acceleration measurement errors caused by the tilt of the pelvis while walking, the estimated walking velocity based on lower-limb kinematics is imposed as the initial value in the acceleration signal integration process of the pelvis inertial sensor. In the experiment involving outdoor walking for six minutes, sensor drift due to error accumulation was not observed, and the RMS error in the walking velocity estimation was less than 0.08 m/s.
Inverse Dynamic Analysis for Various Drivings in Kinematic Systems
Lee, Byung Hoon;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 869-876
Analysis of actuating forces and joint reaction forces are essential to determine the capacity of actuators, to control the mechanical system and to design its components. This paper presents an algorithm that calculates actuating forces(or torques), depending on the various types of driving constraints, in order to produce a given system motion in the joint coordinate space. The joint coordinates are used as the generalized coordinates of a kinematic system. System equations of motion and constraint acceleration equations are transformed from the Cartesian coordinate space to the joint coordinate space using the velocity transformation method. A numerical example is carried out to verify the algorithm proposed.
Analysis of Structural Stability and Optical Performance for Optical Equipment During In-flight Vibr
Jo, Mun Shin;Kim, Sang Won;
Transactions of the Korean Society of Mechanical Engineers A, vol. 41, iss. 9, 2017, pp. 897-904
Optical equipment consists of various components, and a detector is mounted and operated on aircraft, tanks, and warships for target detection and classification. The structural stability and optical performance of aeronautical optical equipment operated at several kilometers of altitude are degraded owing to vibration generated in the aircraft. It is necessary to verify the structural stability and optical performance requirements of the equipment in vibration environment conditions during the design phase. In this study, vibration environment conditions were analyzed using a test standard and the measurements of the vibration generated in aircraft. The conditions were classified as endurance and operating vibration conditions for structural stability and optical performance verification, respectively. The structural stability was verified according to natural frequency analysis, response analysis for the endurance vibration condition, and static analysis. The optical performance was verified by applying the vibration response analysis results to the optical design/analysis program.