• Title/Summary/Keyword: Tooth simulation

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Visualization of Tooth for Non-Destructive Evaluation from CT Images

  • Gao, Hui;Chae, Oksam
    • Journal of the Korean Society for Nondestructive Testing
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    • v.29 no.3
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    • pp.207-213
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    • 2009
  • This paper reports an effort to develop 3D tooth visualization system from CT sequence images as a part of the non-destructive evaluation suitable for the simulation of endodontics, orthodontics and other dental treatments. We focus on the segmentation and visualization for the individual tooth. In dental CT images teeth are touching the adjacent teeth or surrounded by the alveolar bones with similar intensity. We propose an improved level set method with shape prior to separate a tooth from other teeth as well as the alveolar bones. Reconstructed 3D model of individual tooth based on the segmentation results indicates that our technique is a very conducive tool for tooth visualization, evaluation and diagnosis. Some comparative visualization results validate the non-destructive function of our method.

The Study for Estimation of the Surface Temperature Rise in Spur Gear Tooth (Spur Gear 치면의 표면상승온도 예측에 관한 연구)

  • 김희진;구영필;조용주
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.2
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    • pp.331-337
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    • 2001
  • A numerical simulation of the temperature rise for sliding surface in dry contact is based on Jaegers formula combined with a calculated heat input. A gear tooth temperature analysis was performed. The pressure distribution has the Hertzian pressure distribution on the heat source. The heat partition factor is calculated along ling of action. A Temperature distribution of tooth surface is calculated about before and after profile modification. A Temperature of addendum and deddendum in modified gear have reduced.

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Segmentation of tooth using Adaptive Optimal Thresholding and B-spline Fitting in CT image slices (적응 최적 임계화와 B-spline 적합을 사용한 CT영상열내 치아 분할)

  • Heo, Hoon;Chae, Ok-Sam
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.4
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    • pp.51-61
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    • 2004
  • In the dental field, the 3D tooth model in which each tooth can be manipulated individually is an essential component for the simulation of orthodontic surgery and treatment. To reconstruct such a tooth model from CT slices, we need to define the accurate boundary of each tooth from CT slices. However, the global threshold method, which is commonly used in most existing 3D reconstruction systems, is not effective for the tooth segmentation in the CT image. In tooth CT slices, some teeth touch with other teeth and some are located inside of alveolar bone whose intensity is similar to that of teeth. In this paper, we propose an image segmentation algorithm based on B-spline curve fitting to produce smooth tooth regions from such CT slices. The proposed algorithm prevents the malfitting problem of the B-spline algorithm by providing accurate initial tooth boundary for the fitting process. This paper proposes an optimal threshold scheme using the intensity and shape information passed by previous slice for the initial boundary generation and an efficient B-spline fitting method based on genetic algorithm. The test result shows that the proposed method detects contour of the individual tooth successfully and can produce a smooth and accurate 3D tooth model for the simulation of orthodontic surgery and treatment.

Development of Design Theory on the Tooth Arrangement of the Combine Threshing Drum (콤바인 탈곡치(脫穀齒) 배열(配列)의 설계(設計) 이론(理論))

  • Chung, C.J.;Choi, J.S.;Lee, W.S.;Chung, S.I.
    • Journal of Biosystems Engineering
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    • v.17 no.2
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    • pp.171-176
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    • 1992
  • This study was intended to develop the design theory of the threshing unit of a head-feeding rice combine. It may be applied for various combining capacities with different cutting widths and forward speeds. Design factors in the theoretical development are : (1) dimensions of the threshing drum, (2) tooth approching angle, (3) distance between the adjacent teeth on their spiral setting line, (4) number of spirals, and (5) total number of teeth on the drum. A computer simulation program was developed to predict the proper dimensions for the threshing drum and tooth arrangement. A simulation for the prospective combine with varied capacities was also demonstrated. The parameters analyzed in the developed design theory were shown to be consistent with those of existing combines.

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Tooth Modification for Spur Gear for Articulated Hauler's Final Drive (트럭 최종감속기 평기어의 치형최적화에 관한 연구)

  • Oh, Sew-Oong;Zhang, Qi;Lee, In-Bum;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.5
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    • pp.42-47
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    • 2012
  • Construction equipment is heavily loaded during normal operation. In recent years, there is a trend that lower gear noise levels are demanded for drivers to avoid annoyance and fatigue during operation. For articulated hauler's final drive, meshing transmission error(T.E.) is the excitation that leads the tonal noise known as gear whine, and radiated gear whine is also the dominant source of noise in the whole gearbox. This paper presents a method for the analysis of the tooth profile modification, and the prediction of transmission error under the loaded torques for the spur gear pair of the articulated hauler's final drive. And the transmission error, transmission error harmonics and contact stress are also calculated and compared before and after tooth modification under one torque. The simulation result shows that the transmission error and contact stress under the loads can be minimized by the appropriate tooth profile modification.

A Study on Optimization of Tooth Micro-geometry for a Helical Gear Pair (헬리컬 기어의 치형최적화에 관한 연구)

  • Zhang, Qi;Kang, Jae-Hwa;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.4
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    • pp.70-75
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    • 2011
  • Nowadays, modern gearboxes are characterized by high torque load demands, low running noise and compact design. Also durability of gearbox is specially a major issue for the industry. For the gearbox which used in wind turbine, gear transmission error(T.E.) is the excitation that leads the tonal noise known as gear whine, and radiated gear whine is also the dominant source of noise in the whole gearbox. In this paper, tooth modification for the high speed stage is used to compensate for the deformation of the teeth due to load and to ensure a proper meshing to achieve an optimized tooth contact pattern. The gearbox is firstly modeled in Romax software, and then the various combination analysis of the tooth modification is presented by using Windows LDP software, and the prediction of transmission error under the loaded torque for the helical gear pair is investigated, the transmission error, contact stress, root stress and load distribution are also calculated and compared before and after tooth modification under one torque condition. The simulation result shows that the transmission error and stress under the loads can be minimized by the appropriate tooth modification.

Development of Press Forming Technology for the Multistage Fine Tooth Hub Gear (다단 미세 치형 허브기어의 프레스 성형기술개발)

  • Kim Dong-Hwan;Ko Dae-Cheol;Lee Sang-Ho;Byun Hyun-Sang;Kim Byung-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.6 s.183
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    • pp.44-51
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    • 2006
  • This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product for the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

Development of Press Forming Technology for the Multistage Fine Tooth Hub Gear (다단 미세 치형 허브 기어의 프레스 성형기술개발)

  • Kim D.H.;Lee J.M.;Lee S.H.;Byun H.S.;Kim B.M.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.769-772
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    • 2005
  • This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product fur the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

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Single-tooth dento-osseous osteotomy with a computer-aided design/computer-aided manufacturing surgical guide

  • Kang, Sang-Hoon;Kim, Moon-Key;Lee, Ji-Yeon
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.42 no.2
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    • pp.127-130
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    • 2016
  • This clinical note introduces a method to assist surgeons in performing single-tooth dento-osseous osteotomy. For use in this method, a surgical guide was manufactured using computer-aided design/computer-aided manufacturing technology and was based on preoperative surgical simulation data. This method was highly conducive to successful single-tooth dento-osseous segmental osteotomy.