• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.95-103
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• 1996

This paper describes a computer aided design system for spur and helical gears. To establish the appropriate program, an integrate approach based on a rule-base system was adopted. This system is implemented on the personal computer and its environment is a commercial CAD package called AutoCAD. This system includes a main program and five sub-modules such as data input module, tooth profile drawing module, strength calculation module, and drawing edit module. In the main program, all the sub-modules are loaded and the type of gear and tooth profile are selected. In the data input module, the variables which are necessary to the design of gear are selected from the database. In the drawing module, from the calculated results, the required gear tooth is produced on the screen. The developed system that aids gear designer provides powerful capabilities for gear design.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.1
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• pp.101-124
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• 1996

In this study, we designed the finite element models of mandible with varying their connecting types between the prosthesis on implant fixture and 2nd premolar, which were free-standing case(Mf), precision attachment case(Mp), semiprecision attachment case(Ms) and telescopic case(Mt). The basic model of the designed finite element models, which contained a canine and the 1st & 2nd premolar, was implanted in the edentulous site of the 1st & 2nd molar by two implant fixtures. We applied the load in all models by two ways. A vertical load of 200N was applied at each central fossa of 2nd premolar and 1st implant. A tilting load of 20N with inclination of $45^{\circ}$ to lingual side was applied to buccal cusp tips of each 2nd premolar and 1st implant. And then we analyzed three-dimensional finite element models, making a comparative study of principal stress and displacement in four cases respectively. Three-dimensional finite element analysis was performed for the stress distribution and the displacement using commercial software(IDEAS program) for SUN-SPARC workstation. The results were as follows : 1 Under vertical load or tilting load, maximum displacement appeared at the 2nd premolar. Semiprecision case showed the largest maximum displacement, and maximum displacement reduced in the order of precision attachment, free-standing and telescopic case. 2. Under vertical load. the pattern of displacement of the 1st implant appeared mesio-inclined because of the 2nd implant splinted together. But displacement pattern of the 2nd premolar varied according to their connection type with prosthesis. The 2nd premolar showed a little mesio-inclined vertical displacement in case of free-standing and disto-inclined vertical displacement due to attachment in case of precision and semiprecision attachment. In telescopic case, the largest mesio-inclined vertical displacement has been shown, so, the 1st premolar leaned mesial side. 3. Under tilting load, The pattern of displacement was similar in all four cases which appeared displaced to lingual side. But, the maximum displacement of 2nd premolar appeared larger than that of the first implant. Therefore, there was large discrepancy in displacement between natural tooth and implant during tilting load. 4. Under vertical load, the maximum compressive stress appeared at the 1st implant's neck. Semiprecision attachment case showed the largest maximum compressive stress, and the maximum compressive stress reduced in the order of precision attachment, telescopic and free-standing case. 5 Under vertical load, the maximum tensile stress appeared at the 2nd implant's distal neck. Semiprecision attachment case showed the largest maximum tensile stress, and the maximum tensile stress reduced in the order of precision attachment, telescopic and free-standing case. 6. Under vertical load or tilting load, principal stress appeared little between natural tooth & implant in free-standing case, but large principal stress was distributed at upper crown and distal contact site of the 2nd premolar in telescopic case. Principal stress appeared large at keyway & around keyway of distal contact site of the 2nd premolar in precision and semiprecision attachment case, appearing more broad and homogeneous in precision attachment case than in semiprecision attachment case.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.656-664
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• 2016

Gear reducers are widely used for various agricultural machinery applications such as greenhouses, tractors, and agricultural vehicles. However, thermal deformation and surface pitting at gear tooth flank frequently occur in gear reducers due to high torque. Thus, surface heat treatment of gears is required to improve wear and fatigue resistance. The objective of this study was to simulate the load capacity of the agricultural gear reducer. The simulation was performed for the following three surface heat treatment methods: untreated gears, nitriding heat treatment, and induction hardening method, those mostly used for agricultural gear reducers. The load capacity of the gear reducer was simulated using the safety factor, limit bending stress, and limit contact stress of the gear. The simulation of the load capacity was conducted using KISSsoft commercial software for gear analysis. The main results of simulation test were as follows: first, the nitriding heat treatment resulted in the highest safety factor for bending stress, which was increased about 77% from those of the untreated gears. Second, the induction hardening was the highest safety factor for contact stress, which was increased about 150% from those of the untreated gears. The safety factor for contact stress of the induction hardening was increased about 64% from those of the nitriding heat treatment. The study result suggested that the surface heat treatments could enhance load capacity and that the method of surface heat treatment should be determined based on simulation results for appropriate use scenarios.

• Journal of Technologic Dentistry
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• v.41 no.4
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• pp.295-301
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• 2019

Purpose: This study is for the prosthesis of dogs. Observe the occlusal relation between the dog's canine and carnassial teeth. The strength and the direction of the occlusal by 3D FEM analysis. Methods: The mandibular canine and carnassial of dogs were tested. The dog's skull was contact point confirmed by dental CAD. The skull of the dog was 3D modeled by CT. The 3D model was analyzed by ABAQUS. Opening and closing movement has been a force of 100N, 200N, 300N, 500N, 1000N, 1,500N. The peak von Mises stress distribution was confirmed. Results: As occlusal force increased, stress appeared to 1.34 MPa, 3.32 MPa, 5.00 MPa, 6.19 MPa, 5.58 MPa, 5.47 MPa in left canine. and Stress was seen at 2.10 MPa, 3.08 MPa, 3.89 MPa, 5.50 MPa, 7.04 MPa, 7.18 MPa in the right canine. Stress appeared at 2.41 MPa, 3.53 MPa, 5.15 MPa, 7.28 MPa, 31.26 MPa, 67.22 MPa in the left carnassial. and Stress was seen at 1.57 MPa, 2.96 MPa, 3.76 MPa, 6.01 MPa, 20.94 MPa, 64.38 MPa in the right carnassial. Conclusion: Peak von Mises stress values were found at the peak of the canine, the buccal of the central cusp of the carnassial, and the occlusal surface of the distal cusp.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.242-247
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• 1998

The conventional closed-die forging processes had been applied to forging of the spur gears. But this type process requires high pressure. The commercial finite element analysis code ANSYS for the stress and elastic deformation of non-axisymmetric die was adopted in this study. In the non-axisymmetric die such as gear forging, maximum stresses were imposed on the tip of the gear tooth. When the stress exceeds yield strength of insert die, many approaches were attemped to prevent the die failure. Good shaped products are forged successfully. This type process could by used as an advanced technique to replace conventional hobbing process of gear.

• Journal of Drive and Control
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• v.17 no.1
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• pp.1-12
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• 2020

This study was to develop a simulation model of a compound planetary gear reducer for the final driving shaft using a gear analysis software (KISSsoft, Version 2017, KISSsoft AG, Switzerland). The aim of this study is to analyze transmission error and the tooth load distribution through micro-geometry using the simulation model. The tip and root relief were modified with Micro-geometry in the profile direction, and crowning was modified with Micro-geometry in the lead direction. The transmission error was analyzed using the PPTE (Peak to Peak Transmission Error) value, and the tooth load distribution was analyzed for the concentrated stress on the tooth surface. As a result of modifying tip and relief in the profile direction, the transmission error was reduced up to 40.7%. In the case of modifying crowning in the lead direction, the tooth load was more evenly distributed than before and decreased the stress on the tooth surface. After modifying the profile direction for the 1st and 2nd planetary gear train, the bending and contact safety factors were increased by 31.7% and 17%, and 18.3% and 12.5% respectively. Moreover, the bending and safety factors after modifying lead direction were increased by 59.5% and 32.7%, respectively for the 1st planetary gear train, and 59.6% and 43.6%, respectively for the 2nd planetary gear train. In future studies, the optimal design of a compound planetary gear reducer for the final driving shaft is needed considering both the transmission error and tooth load distribution.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.142-151
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• 2013

This study develops an automation system for metallic mold design that is applicable in forging non-axial symmetric parts. The metallic mold design program is used to design the metallic mold using two-dimensional axial symmetric metallic molds and to predict the stress concentration using finite element analyses. Then, the program redesigns the metallic mold using variables such as the optimal split diameter, maximum allowable inner pressure, fit tolerance, and stress distribution, which are calculated using the metallic mold design program. When the involute spur gear is forged, stress concentration occurs on the tooth root bounded at the symmetric surface. The SCM4 material is suitable for metallic molds because the stress is less than the yield strength of the insert and it acts on the tooth root regardless of the inner pressure. The metallic mold for forging non-axial symmetric parts can be designed through adjusting the magnitude of the contact pressure. The program developed in this study can be applied to metallic mold designs in involute spur gears of forging, which is an ordinary non-axial symmetric part.

• The Journal of Advanced Prosthodontics
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• v.10 no.3
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• pp.184-190
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• 2018

PURPOSE. To analyze stress distribution in premolars restored with inlays or onlays using various materials. MATERIALS AND METHODS. Three-dimensional maxillary premolar models of abutments were designed to include the following: 1) inlay with O cavity (O group), 2) inlay with MO cavity (MO group), 3) inlay with MOD cavity (MOD group), and 4) onlay (ONLAY group). A restoration of each inlay or onlay cavity was simulated using gold alloy, e.max ceramic, or composite resin for restoration. To simulate masticatory forces, a total of 140 N static axial force was applied onto the tooth at the occlusal contact areas. A finite element analysis was performed to predict the magnitude and pattern of stresses generated by occlusal loading. RESULTS. Maximum von Mises stress values generated in the abutment teeth of the ONLAY group were ranged from 26.1 to 26.8 MPa, which were significantly lower than those of inlay groups (O group: 260.3-260.7 MPa; MO group: 252.1-262.4 MPa; MOD group: 281.4-298.8 MPa). Maximum von Mises stresses generated with ceramic, gold, and composite restorations were 280.1, 269.9, and 286.6 MPa, respectively, in the MOD group. They were 252.2, 248.0, 255.1 MPa, respectively, in the ONLAY group. CONCLUSION. The onlay design (ONLAY group) protected tooth structures more effectively than inlay designs (O, MO, and MOD groups). However, stress magnitudes in restorations with various dental materials exhibited no significant difference among groups (O, MO, MOD, ONLAY).

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.283-289
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• 2012

Cam rack pinion (CRP) system which consists of cam rack and roller pinion transforms the rotation motion into linear one. The roller pinion has the plurality of rollers and meshes with its conjugated cam rack. The exact tooth profile of the cam rack and the non-undercut condition to satisfy the required performance have been proposed by introducing the profile shift coefficient. The load stress factors are investigated by varying the shape design parameters to predict the gear surface fatigue limit which is strongly related to the gear noise and vibration at the contact patch. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.422-427
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• 2000

Gear design carried in former type determined a few variables like module, pressure angle, helix angle. After investigating repeatedly results obtained through stress analysis and making a determination an optimal shape, but its design process was not only complex but also difficult to get a precise profile curve from operating by hand. In this study, rotating shape of gear profile curves were generated automatically with standard spur gear, equivalent helical gear, shifted gear & pinion by using developed program which is Auto_LISP language supported in Auto-CAD. Output tooth profile by using CAE program is applied as Preprocessor for stress analysis in each contact points. This program which can be determined rapidly an optimal shape of gear will be successfully supported for Small & Medium companies designing and manufacturing gears by using Auto-CAD.