• Archives of Plastic Surgery
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• v.37 no.6
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• pp.779-782
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• 2010

Purpose: As the evaluation of the preoperative sensibility in the orbitozygomatic complex fracture, used by most surgeons, depends on the patient's subjective judgements, it is difficult to make generalization and to use it as an objective evaluation method. We used the blink reflex study to objectively evaluate injury to the infraorbital nerve. Methods: From December 2008 to November 2009, a total of 16 patients underwent the patient's subjective report on sensory symptoms and the blink reflex study preoperatively. Among patients having orbitozygomatic complex fracture of type III or more according to Henderson's classification and simultaneously suspected as being injured along the infraorbital nerve pathway, patients who had difficulty in checking preoperative sensibility and said 'normal sensibility' were selected as candidates. Results: Fifteen patients showed abnormal R1 on the fracture side. These results suggested that most of patients had injury to the infraorbital nerve. Conclusion: Contrary to the existing tests, the blink reflex study is a useful diagnostic tool in reflecting injury to the infraorbital nerve objectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.61-67
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• 1999

In turning the chip may be produced in the form of continuous chip or discontinuous one. Continuous chips produced at high speed machining may hit the newly cut workpiece surface and adversely affect the appearance of the surface finish and may interfere with tool and sometimes induce tool fracture. In this study relationship between AE signal and chip form was experimentally investigated, The experimental results show that types of chip form are possible to be classified from the AE signal using fuzzy logic.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.107-113
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• 1996

This paper presents the experimental results on the cutting performance and wear characteristics of CBN ball end-mill. The influence of cutting fluids and rake angles on the tool performance is reported. It i found that the neat cutting oil is beneficial to obtain good surface roughness and 30 .deg. of rake angle gives the minimum tool wear. The microscopic investigations reveal that the coated carbide endmills wear by fracture whereas the CBN endimills wear by attritious mode.

• Archives of Craniofacial Surgery
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• v.20 no.5
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• pp.284-288
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• 2019

Background: Closed reduction of nasal fracture with various instrument is performed to treat nasal fracture. Depending on the type of nasal fracture and the situation in which it is being operated, the surgeon will determine the surgical tool. The objective of this study was to investigate whether a periosteal elevator (PE) was a proper device to perform closed reduction for patients with simple nasal fractures. Methods: From March 2018 to December 2018, 50 cases of simple nasal bone fracture underwent closed reduction performed by a single surgeon. These patients were divided into two groups randomly: nasal bone reduction was performed using only PE (freer) and nasal bone reduction was performed using Walsham, Asch forcep, and Boies elevator (non-freer, non-PE). Results: The paranasal sinus computed tomography was performed on patients before and after operation to carry out an accurate measurement of reduction distance at the same level. According to the results, the interaction between instruments and fracture types had a significant influence on reduction distance (p = 0.021). To be specific, reduction distance was significantly (p= 0.004) increased by 2.157 mm when PE was used to treat patients with partial displacement compared to that when non-PEs were used. Conclusion: Closed reduction using PE and other elevator is generally an effective treatment for nasal fracture. In partial-displacement type of simple nasal fracture, closed reduction using PE can have considerable success in comparison with using classic instruments.

• Composites Research
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• v.21 no.4
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• pp.7-14
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• 2008

Prediction of the load-bearing capacity of an adhesive-bonded Joint is of practical importance for engineers. This paper introduces interface fracture mechanics approach to predict the load-bearing capacity of composite metal bonded joints. The adhesion strength of composite/steel bonding is evaluated in terms of the energy release rate of an interfacial crack and the fracture toughness of the interface. Virtual track closure technique (VCCT) is used to calculate energy release rates, and hi-material end-notched flexure (ENF) specimens are devised to measure the interfacial fracture toughness. Bi-material ENF specimens gave consistent mode II fracture toughness $(G_{IIc})$ values of the composite/steel interface regardless of the thickness of specimens. The critical energy release rates of double-lap joints showed a good agreement with the measured fracture toughness. Therefore. the energy-based interfacial fracture characterization can be a practical engineering tool for predicting the load-bearing capacity of bonded joints.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.298-303
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• 2001

Most of mechanical failures are caused by repeated loadings and therefore they are strongly related to fatigue. To avoid the failures caused by fatigue, determination of an optimal shape of a structure is one of the very important factors in the initial design stage. Shape optimization for a compact tension specimen in opening mode in fracture mechanics, was accomplished by the linear elastic fracture mechanics and the growth-strain method in this study. Also shape optimization for a cantilever beam in mixed mode was carried out by the same techniques. The linear elastic fracture mechanics was used to estimate stress intensity factors and fatigue lives. And the growth-strain method was used to optimize the shape of the initial shape of the specimens. From the results of the shape optimization, it was found that shapes of two types of specimens and a cantilever beam optimized by the growth-strain method prolong their fatigue lives very much. Therefore, it was verified that the growth-strain method is an appropriate technique for shape optimization of a structure having a crack.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.40-45
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• 2001

The relationship between structural geometry and number of life cycles to failure is investigated to improve the fatigue life of structural components. The linear elastic fracture mechanics(LEFM) approach is integrated with shape optimal design methodology. The primary objective of this study is to decide an optimal shape for enhancing the life of the structure. The results from LEFM analyses are used in the fatigue model to predict the life of the structure before failure is occurred. The shape of the structure is optimized by using the growth strain method. Relevant issues such as problem formulation, finite element modeling are explained. Three design examples are solved, and the results show that, with proper shape changes, the life of structural systems subjected to fatigue loads can be enhanced significantly.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.287-292
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• 1998

In this study behavior of fatigue crack and fatigue fracture is observed under rotary bending fatigue testing in friction welded dissimilar materials. Fatigue fracture most occurred in SM15C heat affected zone around Interface. In case of fatigue test, stress is reduced the position of fracture gradually moves to the welded Interface. Micro crack of heat affected zone surface on SM15C is observed at any different stress.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.24-29
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• 2005

Optimal heat treatment process in martensitic stainless steel such as SUS416 is investigated. The approach is based on the combination of the interpolation and extrapolation method of a standard heat treatment technology with the principle of quenching and tempering temperature difference. The relationship of the macroscopic structure, fracture toughness and ductility as well as the hardness and strength are considered to induce a simple rule to apply with feasibility. Consequently, Optimal heat treatment condition in martensitic stainless steel is proposed and is shown the better quality. It was found that the smaller pain size of microstructure gives the enhanced fracture toughness and ductility.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.134-140
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• 2000

Tube hydroforming is a relatively new technology compared to conventional stamping. thus there is little knowledge base that can be utilized for process and die design. To remedy this situation considerable research is now being conducted by many researchers on significant aspects of tube hydroforming technology including material selection pre-form design hydroforking process and tool design. in the tube hydroforming process we frequently experence many failure modes like wrinkling. buckling folding back and fracture under the improper forming conditions. In this paper forming limit for failure occurrence such as fracture and wrinkling is examined theoretically and the result is compared with Back's experimental result.