• Plant Journal
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• v.8 no.2
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• pp.59-69
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• 2012

This study focuses on avoiding the failures from the wrong selections by experiences as simulation programs is not available, and suggests the methods which effectively select the alternatives when the selected model is not appropriate for the original plan. First, CC8800-1K of DEMAG has the longest boom whose length is 216 m at the maximum. The combination of the boom is feasible to second level except for MANITIWOC M 2250 (M-1200 RINGER) which is possible to third level. Second, the angle of boom is from 20 degrees to 82 degrees. Suitable angle to work is in the 55-78 degrees. The working load of crawler type and hydraulic one to be applied is 75-85% in the critical loads capacity. As increasing operating radius, crawler type is a favorable position over hydraulic one. Lastly, related problems were verified through examination by suggestions for the design of the selection methods for the case analysis. The major problems are stemming from the selection based on its experiences, unreasonable demand for the existing facility and repeated selections by the designer who accumulates his experiences via same or similar projects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.577-578
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• 2007

• Journal of Biosystems Engineering
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• v.10 no.1
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• pp.13-23
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• 1985

Spraying method from the paddy-field levee is known to give insufficient penetration of the spray droplets to the rice stem of the densely grown plants, which is generally encountered at the last stage of rice growth. This study was intended to investigate the spraying system to solve this existing problem. As an approach, it was attempted to develop the boom-with-nozzle, between-the-row application system. Several types of nozzles and their different arrangements in the boom were tested in the field to measure the penetration-reaching distance and the uniformity of spray droplet distribution. The results of the study are summarized as follows: 1. Field experiments by the spraying method from the paddy-field levee showed to have practically no penetration of the spray droplets to the portion of the plant stem with the normal flow volume generally applied and thus need for improving present spraying method. 2. It was found that, considering both the uniformity of the spray droplet distribution and performance rate, the most efficient type of nozzle in the between-the-row boom-type spraying system was one that has core-insert hollow-cone with some clearance between the cone and tip. 3. When tested by applying the spraying method of between-the-row, the nozzle pressure did not affect the uniformity of spray droplet distribution. However, the nozzle pressure had a positive effect on the penetrating-reaching distance of the facing side of the rice stem and did not affect much on that of the opposite face of the stem. It was also found that the maximum pressure to affect the penetration-reaching distance was about $10kg/cm^2$. 4. The uniformity of the spray droplet distribution in the between-the-row system was greatly affected by the height and orientation of the nozzles in the boom. Based on experimental work for the different type of the boom-with-nozzle arrangements, it is recommended that the position of nozzle is set at about 0.45 m above the ground and two nozzles in the boom are oriented to be faced with each other with some angle such that the droplet stream from the nozzle would not directly face with each other.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.6
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• pp.28-35
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• 1998

Computer simulation technique has been applied on the various engineering fields to reduce cost and development period. On this paper, we introduce a crane analysis program. Using this program, we can predict reaction force of each part or supporting force of truck crane on a personal computer system with out exclusive knowledge of multi-body dynamics. In order to consider the effect of boom flexibility according to each working condition, flexible dynamic theory is applied to the program. Actual crane model is analyzed on special work condition using this program and the results are compared with those of rigid boom model.

• Journal of Power System Engineering
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• v.22 no.1
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• pp.25-33
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• 2018

The safety of structure was evaluated by taking into consideration the complex marine environmental conditions of the Lattice boom crane, which is widely used in offshore plants due to less influence by wind. CFX analysis was carried out to take into account the influence of wind speed, and the result was applied as a boundary condition to perform static analysis according to the luffing angles of $28^{\circ}$, $61^{\circ}$, and $80^{\circ}$ in the on board and off board, respectively. In addition, the Lattice Boom Crane is large slender structure, and the possibility of buckling is interpreted under three conditions where the biggest stress occurs. All conditions satisfied the safety requirements of the Classification Regulations. Also, as a result of the buckling analysis, the load less than the critical load was applied so buckling does not occur.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1265-1273
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• 2015

A coal handling machine is a type of equipment used for loading coal, the main material in a steam power plant, along a conveyer belt from a ship, and is placed after the driving chain bucket. However, studies on the boom hoisting cylinder, which is a hydraulic system used to control the angle of the boom based on loading location, indicate that domestic models are insufficient, and are thereby often substituted with a foreign product. In this study, a technique for analyzing the contact pressure in a thick-walled cylinder was established by comparing the contact pressure, which is calculated theoretically based on the results obtained from FEM simulation, and by checking whether the working oil is leaking from the boom hoisting cylinder using a v-seal. In addition, the driving motion was simulated according to the strokes of the cylinder, and the structural stability was verified under the maximum output conditions.

• Bulletin of the Society of Naval Architects of Korea
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• v.18 no.3
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• pp.59-63
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• 1981

With substitution with a delicate turn-tree instead of a long permanent cross-tree that is usally located on the derrick post, it is possible to get a large working range of the slewing angle 240 degree and also to decrease the slewing time of the derrick boom, comparing to the exisiting cargo gear system which has the same capacity of slewing winch.

• Journal of Biosystems Engineering
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• v.35 no.4
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• pp.215-223
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• 2010

In order to develop an precision aerial pesticide application system to be attached to an unmanned helicopter which can be applied to small lots of land, this study analyzed the flowing and spraying characteristics of the spray droplets by the main rotor downwash by setting the application conditions at the flight altitude of 3 m, the diameter of main rotor of 3.1 m, the boom length of around 2.8 m, and the spraying rate of 8 L/ha. The results of this study are summarized below. Through analysis of the covering area ratio of the spray droplets by main rotor downwash by nozzle type, boom with tilt angle and height, it was found that the covering area ratio of the twin flat-fan nozzle of around 25% was more uniform than other types of nozzle, also boom with $10^{\circ}$ tilt angle and spraying height of 3 m was shown to be the appropriate conditions for aerial application of pesticides. It was found that the nozzle position to minimize the scattering loss of spray droplets due to vortex phenomenon at both ends of the main rotor was around 10 cm from the end of the main rotor. An application test for the aerial pesticide application system attached to the HUA-ACEI unmanned helicopter developed by the Rural Development Administration showed that the range of covering area ratio of the spray droplets was 10-25%, and the spraying width was approximately 7 m when over 10% of covering area ratio was considered for valid spraying.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.617-622
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• 2011

In this paper, the structural analysis is carried out with the vertical loading condition on the platform of the high place working vehicle. The model of analysis is reduced on the scale of 1:10. Deformation and stress distribution of boom are analyzed with the variation of angle at boom position and the vulnerable parts are checked. Analysis result shows that most stress is concentrated at the connection of the boom. Through this analysis result, the safety on this vehicle can be improved by making up for the relatively weak connection parts as compared with other parts.

• Journal of Drive and Control
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• v.20 no.4
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• pp.9-16
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• 2023

This paper analyzed a drainage tower used to drain water in flooded areas. Multi-body dynamics simulation was used to analyze the dynamic behavior of the drainage tower. Structural analysis, flexible-body dynamic analysis, and rigid body dynamic analysis were done to study the maximum Von-Mises stress of the drainage tower. The results showed that the maximum Von-Mises stress occurs at the turn table, and it decreases when the angle of the boom is increased. Also, the rate of the change of angle affects the maximum stress so that the maximum stress changes more when the angular velocity of the boom increases. Based on the rigid body dynamic analysis and the theoretical analysis results, the centrifugal force from the angular velocity makes the difference in the maximum stress at the turn table because of the difference in their direction. Consequently, it was concluded that the centrifugal force should be considered when designing construction machinerythat can rotate.