Papers by Author: Geun Jo Han

Abstract: The brake system is very important part of the machine working. The mooring winch brake holds the ship on the harbor. But sometimes it appeared the excessive stress and brake lining would be broken. So it is necessary to change the shape of brake system with improve the durability of brake band. In this research, three models, such as a single brake shoe with a uniform thickness, a dual brake shoe with a uniform thickness, and a dual brake shoe with different thickness, are adopted as analytic model. In order to evaluate the strength of band brake according to the shape of brake shoe, the finite element analysis for three models is carried out by using ANSYS Workbench.

Abstract: This study is conducted to provide a compensation formula to design the stowing devices - a tie-down rod and a stowage pin - and an alarm system to prevent an overturning of a container crane under wind loads. Two method, namely FSI(fluid-structure interaction) analysis and wind tunnel test, are adopted in this investigation. In order to evaluate the effect of wind load on the stability of the crane, 50-ton class container crane widely used in container terminals is adopted for analytic model and 19-values are considered for wind direction as design parameter. First, the wind tunnel test for the reduced scale container crane model is performed according to the wind direction using an Eiffel type atmospheric boundary-layer wind tunnel. Next, FSI analysis for a full-scale container crane is conducted using ANSYS and CFX. Then, the uplift force obtained from FSI analysis is compared with that yielded by the wind tunnel test. Finally, a formula is suggested to compensate the difference between the FSI analysis and the wind tunnel test.

Abstract: An overload limiter is used to prevent its overturning accident during an operating of a movable crane. Recently the indirectly measuring method, which measures hoisting load and overturning moment of overload limiter, demands instead of the existing method, which measures only hoisting load. The indirectly measuring method is how to conduct the hoisting load and overturning moment as measuring the load of hydraulic cylinder for a luffing driving of boom. So we need to develop the many-angular pin type load cell with the measuring angle of ±10 degree instead of the existing load cell with the measuring angle of ±2 degree. In this study we conducted the finite element analysis in order to evaluate the effect of the aspect ratio of measuring cross section on the measuring limit of the load cell to develop the many-angular pin type load cell. For this investigation, the aspect ratio of measuring cross section and load applying angle were adopted as design parameters and the stresses of measuring part were evaluated for each parameter.

Abstract: In this study we carried out to analyze the effect of wind load on the structural stability of a container crane according to the change of the boom shape using wind tunnel test and provided a container crane designer with data which can be used in a wind resistance design of a container crane assuming that a wind load at 75m/s wind velocity is applied on a container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of a container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Eiffel type atmospheric boundary-layer wind tunnel with 11.52m2 cross-section area. Each directional drag and overturning moment coefficients were investigated.

Abstract: This study was carried out to analyze the effect of wind load on the stability of an articulation type container crane using wind tunnel testing. This was done in order to furnish designers with data that can be used in the design of an articulation type container crane that is wind resistant, assuming an applied wind load of 75m/s velocity. Data acquisition conditions for this experiment were established in accordance with similarity. The scale of the articulation type container crane model, wind speed and time were chosen as 1/200, 1/13.3 and 1/15 respectively and this experiment was conducted using an Eiffel type atmospheric boundary-layer wind tunnel with 11.52m2 cross-sectional area. All directional drag and overturning moment coefficients were investigated and uplift forces due to wind load at each supporting point were analyzed.

Abstract: The rail clamp is the device to prevent that a container crane slips along rails due to the wind blast as well as to locate the crane in the set position through loading and unloading containers on a vessel in the quay. In order to design the rail clamp, we need to determine the proper wedge angle to minimize the sliding distance of a roller and the proper clamping angle of a locker to generate the initial clamping force of a jaw pad. The researches for the proper wedge angle have conducted. So in this study we look into the relationship between the clamping angle of a locker and the initial clamping force in the rail clamp with wedge angle of 10
. The initial clamping force of the jaw pad was determined by the clamping angle of the locker. Therefore after we measured the locking force of a locker and the tensile stress of extension bar with respect to the clamping angle of a locker, such as 2.18, 3.05, 3.92, 4.80
, we compared the results with the FEA results.

Abstract: Recently, application of semiconductor sensors has widely spreaded into various industries becasuse those have several merits like easy miniaturization and batch production etc. But external conditions such as thermal and repetitive load have a bad effect on sensors’s lifetime. Therefore, lots of studies related with the fatigue of microelectromechnical systems (MEMS) have been conducted. Especially, this paper was focused on fatigue life of aluminum interconnect in the supporting structure of sensor under cyclic thermal load and on the approximation equation defining the critical temperature to ensure required operating life using FEM simulation.