Measurement of the dimensions of a cylindrical component with axial terminations

2015 ◽  
2011 ◽  
Vol 325 ◽  
pp. 35-41 ◽  
Author(s):  
Thai Nguyen ◽  
Liang Chi Zhang ◽  
Da Le Sun

A three-dimensional finite element heat transfer model incorporating a moving heat source was developed to investigate the heat transfer mechanism in grinding-hardening of a cylindrical component. The model was applied to analyze the grinding-hardening of quenchable steel 1045 by two grinding methods, traverse and plunge grinding. It was found that the heat generated can promote the martensitic phase transformation in the ground workpiece. As a result, a hardened layer with a uniform thickness can be produced by traverse grinding. However, the layer thickness generated by plunge grinding varies circumferentially. The results are in good agreement with the experimental observations.


2020 ◽  
Vol 56 (5) ◽  
pp. 397-407
Author(s):  
Yongjun Li ◽  
Zeyong Wang ◽  
Yu Zhang ◽  
Jianping Peng ◽  
Xiaorong Gao

2020 ◽  
Vol 17 (2) ◽  
pp. 209-215
Author(s):  
Е. P. Gurmizov ◽  
К. B. Pershin ◽  
N. F. Pashinova ◽  
А. Iu. Tsygankov

Purpose. Evaluation of the visual and refractive results of additional correction using LASIK and PRK methods in patients with residual refractive error after previous cataract surgery. Patients and methods. The prospective open study included 57 patients (79 eyes) who previously underwent cataract phacoemulsification (n = 37) or refractive lensectomy (n = 42) with various IOL models implantation (2012–2017). The average age of patients was 50.8 ± 13.9 (19–79) years. Operations LASIK (91.1 %) and PRK (8.9 %) were carried out according to standard methods. In 6 cases, femtosecond laser supported by laser correction. The target refraction ranged from –0.25 to 0.25 D in most (97.5 %) cases. The follow-up period ranged from 6 to 9 months. Results. The patients were divided into groups according to the type of residual refractive error (Group 1 — myopia, group II — emmetropia and group III — hyperopia). Statistically significant differences were determined for the species of previously implanted IOLs — in group II, the frequency of monofocal IOLs was significantly higher (p < 0.05). In group II, the values of the cylindrical component of refraction were significantly higher compared with groups I and III (p < 0.05). In group I, a significant (p < 0.05) decrease in the spherical component of refraction from –1.36 ± 0.92 to –0.2 ± 0.8 D was observed. In patients of group II, there was a slight increase in the spherical component of refraction from 0 ± 0.20 to 0.25 ± 0.29 D (p > 0.05). In group III, a significant (p < 0.05) decrease was observed in the spherical component of refraction from 1.27 ± 0.69 to 0.43 ± 0.49 D. When analyzing the cylindrical component of refraction in group I, its decline was noted from –0.69 ± 0.5 to –0.38 ± 0.46 D (p > 0.05). In group II, the largest decrease in the cylindrical component was observed from –1.6 ± 1.0 to 0.03 ± 1.10 Dptr (p < 0.01). In all the studied groups, a statistically significant (p < 0.05) increase in UCFVA was revealed in the postoperative period. Indicators K1 and K2 did not significantly change. Conclusion. The high efficiency of the correction using the LASIK, PRK and femtoLASIK methods on pseudophakic eyes with the achievement of the target refraction in most of the studied cases was shown. This method can be used as an alternative to spectacle and contact correction in patients with residual refractive error after cataract phacoemulsification and refractive lensectomy with IOL implantation.


1993 ◽  
Vol 65 (5) ◽  
pp. 1874-1877
Author(s):  
V. M. Vigak ◽  
Kh. E. Zasadna ◽  
G. A. Il'chenko ◽  
A. V. Kostenko ◽  
Yu. P. Yarmolyuk

2004 ◽  
Vol 81 (1) ◽  
pp. 62-63 ◽  
Author(s):  
Jeremy A. Guggenheim ◽  
Jane E. Farbrother

Author(s):  
Kenji Oyamada ◽  
Shinji Konosu ◽  
Takashi Ohno

Remaining Strength Factor (RSF) approach in Part 5 of API 579-1/ASME FFS-1 is an assessment method for a cylindrical component with a local metal loss based on surface correction factors. Also, reference stress solutions that are applied in the Failure Assessment Diagram (FAD) method for a cylindrical component with a crack-like flaw are provided in Annex D using surface correction factors. In the p-M diagram method that has been recently developed, reference stress solution for local metal loss evaluation in a cylindrical component is derived using bulging factors, which are similar but not identical to the surface correction factors used in API 579-1/ASME FFS-1. This paper describes the results of a comparative study among the RSF approach, reference stress solutions for the FAD method, and the p-M diagram method, in terms of plastic collapse evaluation of a cylindrical component. These results were compared with the FEA and experimental results to confirm how those estimated stresses could be validated. The results of the study also contain proposals for prospective modifications of API 579-1/ASME FFS-1.


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