• Journal of Computational Design and Engineering
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• v.1 no.1
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• pp.27-36
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• 2014

Similar to the essential components of many mechanical systems, the geometrical properties of the teeth of spiral bevel gears greatly influence the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show a unique advantage in transmission due to their constant spiral angle property. However, a mathematical model suitable for accurate digital modeling, differential geometrical characteristics, and related contact analysis methods for tooth surfaces have not been deeply investigated, since such gears are not convenient in traditional cutting manufacturing in the gear industry. Accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed in this study, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry; actually, the tooth surface is a parametric surface defined on a parallelogrammic domain. Equivalence proof of the tooth surface geometry is then given in order to greatly simplify the mathematical model. As major factors affecting the lubrication, surface fatigue, contact stress, wear, and manufacturability of gear teeth, the differential geometrical characteristics of the tooth surface are summarized using classical fundamental forms. By using the geometrical properties mentioned, manufacturability (and its limitation in logarithmic spiral bevel gears) is analyzed using precision forging and multiaxis freeform milling, rather than classical cradle-type machine tool based milling or hobbing. Geometry and manufacturability analysis results show that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multiaxis freeform milling also need to be solved in a further study.

• Journal of KIBIM
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• v.13 no.4
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• pp.26-35
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• 2023

Recently, mandatory BIM design has been enforced in the civil engineering field, focusing on public projects, and inducement measures to actively participate in BIM by participating subjects are required. The BIM ordering documents must reflect the characteristics of the BIM project, current construction standards and laws, and environmental conditions of domestic participants. In this study, we analyze the ordering documents used in domestic and overseas civil engineering BIM projects to determine whether they meet the purpose of BIM. In the future, items that consider the existing heterogeneous data linkage and compatibility, the connectivity with the current construction guidelines and laws, the cost of the designer and the input personnel are prepared for the part that does not meet the BIM purpose. Furthermore, the written order documents are verified through interviews with experts who have experience in BIM projects. Through the results of this study, I would like to propose a consultation system strategy to prepare and present items according to the purpose and type of project by client.