• Proceedings of the KSME Conference
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• 2004.04a
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• pp.353-358
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• 2004

We got the following characteristics from fatigue crack growth test carried out in the environment of room temperature and low temperature at $25^{circ}C$, $-60^{circ}C$, $-80^{circ}C$, and $-100^{circ}C$ in the range of stress ratio of 0.3 by means of opening mode displacement. And there is a difference between shot peened specimen and unpeened specimen. The purpose of this study is to predict the behavior of fatigue crack propagation as one of fracture mechanics on the compressive residual stress. Fatigue crack growth rate of shot peened metal was lower than that of unpeened metal. The compressive residual stress made an impact on tension and compression of the plasticity deformation in fatigue crack plasticity zone. That is. the constrained force about plasticity deformation was strengthened by resultant stress, which resulted from plasticity deformation and compressive residual stress in the process of fatigue crack propagation.

• Journal of Dental Anesthesia and Pain Medicine
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• v.18 no.2
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• pp.115-117
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• 2018

Lingual nerve injury is a rare complication of general anesthesia. The causes of lingual nerve injury following general anesthesia are multifactorial; possible mechanisms may include difficult laryngoscopy, prolonged anterior mandibular displacement, improper placement of the oropharyngeal airway, macroglossia and tongue compression. In this report, we have described a case of bilateral lingual nerve injury that was associated with orotracheal intubation for open reduction and internal fixation of the left distal radius fracture in a 61-year-old woman. In this case, early treatment with dexamethasone effectively aided the recovery of the injured lingual nerve.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.185-194
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• 2006

In this paper, three dimensional finite element analyses have been performed to investigate the biomechanics of vertebroplasty in patient accurate FE models have been constructed from CT images of a PMMA injected vertebra. In order to apply various material properties of the spine(T12), the functional relation between the well known apparent density and HU(Hounsfield unit) from CT image were employed and thus real material properties can be assigned to each element of FE model. The FE analysis showed similar results with the experiments. With this approach accurate analysis of the vertebroplasty and its clinical applications can be expected.

• Knee surgery & related research
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• v.30 no.4
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• pp.284-292
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• 2018

Purpose: As the number of total knee arthroplasties (TKAs) increases, the incidence of femoral periprosthetic fractures after TKA is also increasing. This review aimed to suggest a new surgically oriented classification system for femoral periprosthetic fractures. Methods: We investigated the classifications, and current treatment trends for femoral periprosthetic fractures after TKA by means of a thorough review of the relevant literature. Results: Numerous studies reported good results of surgical treatment with modern fixatives including locking compression plates and retrograde intramedullary nails. However, few classifications of femoral periprosthetic fractures reflect the recent developments in surgical treatment. Conclusions: We recommend that surgical management be considered the first-line treatment for femoral periprosthetic fractures after TKA. Our new classification will help in deciding the surgical treatment option for femoral periprosthetic fractures after TKA.

• Geomechanics and Engineering
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• v.18 no.2
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• pp.111-119
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• 2019

Due to certain geological characteristics (high thickness, rocky properties), some underground coal mines require the use of explosives. This paper explores the effects of fragmentation of different decks detonated simultaneously in a single borehole with the use of numerical analysis. ANSYS/LS-DYNA code was used for the implementation of the models. The models include an erosion criterion to simulate the cracks generated by the explosion. As expected, the near-borehole area was damaged by compression stresses, while far zones and the free surface of the boundary were subjected to tensile damage. With the increase of the number of decks in the borehole, different changes in the fracture pattern were observed, and the superposition effects of the stress wave became evident, affecting the fragmentation results. The superposition effect is more evident in close distances to the borehole, and its effect attenuates when the distance to the borehole increase.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.2
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• pp.115-120
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• 2009

Purpose: To evaluate the outcomes of three different surgical approaches in treating a distal radius fracture with dorsal communition. Materials and Methods: From April, 2006 to May, 2009, 49 patients over age of 60years old with unstable dorsal communition distal radius fracture were analyzed. We compared maintainability of reduction by radiological follow-up observations and clinical outcomes using Mayo wrist scores. One-Way ANOVA test was performed to examine the statistical correlation between the methods. Results: All three approaches provided satisfactory post-op reduction results. However, follow-up observations showed significant loss of reduction in the external fixation only group compared to the added bone graft group and the volar anatomical locking plate group (P<0.05). Mayo wrist score was indifferent between the three groups. Conclusion: Treatment of a distal radius fracture with severe dorsal communition using an external fixation only appears to be insufficient in maintaining reduction of a cancellous bone defect.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.3
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• pp.207-217
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• 2010

The purpose of this study was to evaluate the effects of the stress distribution and displacement in mandible according to treatment modalities of mandibular angle fractures, using a three dimensional finite element analysis. A mechanical model of an edentulous mandible was generated from 3D scan. A 100-N axial load and four masticatory muscular supporting system were applied to this model. According to the number, location and materials of titanium and biodegradable polymer plates, the experimental groups were divided into five types. Type I had a single titanium plate in the superior border of mandibular angle, type II had two titanium plates in the superior tension border and in the inferior compression border of mandibular angle, type III had a single titanium plate in the ventral area of mandibular angle, type IV had a single biodegradable polymer plate in the superior border of mandibular angle, type V had a single biodegradable polymer plate in the ventral area of mandibular angle. The results obtained from this study were follows: 1. Stress was concentrated on the condylar neck of the fractured side except Type III. 2. The values of von-Mises stress of the screws were the highest in the just-posterior screw of the fracture line, and in the just-anterior screw of Type III. 3. The displacement of mandible in Type III was 0.04 mm, and in Type I, II, IV, and V were 0.10 mm. 4. The plates were the most stable in the ventral area of mandibular angle (Type III, V). In conclusion, the ventral area of mandibular angle is the most stable location in the fixation of mandibular angle fractures, and the just- posterior and/or the just-anterior screws of the fracture line must be longer than the other, and surgeons have to fix accurately these screws, and the biodegradable polymer plate also was suitable for the treatment of mandible angle fracture.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.3
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• pp.1-13
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• 1982

Transition process of plastic region. displacements, stresses and strains ahead the flaw tips were analysed by the finite element method on the steel plate with the circular hole and the one with the elliptical hole under completely alternating load (repetition of tensile loading, unloading and compressive loading). As the results, the followings were obtained. Transition process of elastic failure (yielding) region was estimated. From this the tendency was confirmed that the fracture would be initiated from ahead the flaw tip, and propagated along the $45^{\circ}$ direction. The fundamental data available in estimating the stress intensity factor that was considered as the core in analysing the fracture mechanism of steel plates were obtained. It was indicated that when unloading after tension the effect of compressive loading, and even the compressive reyield, was occured ahead the flaw tip. Similarly it was indicated that when unloading after compression the effect of tensile loading, and even the tensile reyield, was occured ahead the flaw tip. It was considered that these phenomena were occured because the unloading effect was constrained by the residual strains when unloading. It was considered that the fatigue phenomenon was occured ahead, the flaw tip by repetition of tensile yield, the above compressive reyield, compressive yeild and the above tensile reyield. In addition, the tendency was confirmed that the fracture ahead the flaw tip was occured as the flaw was changed from the circular hole to the elliptical hole and became to be the crack lastly.

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.345-371
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• 1994

Restorative procedures can lead to weakening tooth due to reduction and alteraton of tooth structure. It is essential to prevent fractures to conserve tooth. Among the several parameters in cavity designs, cavity isthmus and depth are very important. In this study, MO amalgam cavity was prepared on maxillary first premolar. Three dimensional. finite element models were made by serial photographic method and cavity depth(1.7mm, 2.4mm) and isthmus (11 4, 1/3, 1/2 of intercuspal distance) were varied. linear, eight and six-nodal, isoparametric brick elements were used for the three dimensional finite element model. The periodontal ligament and alveolar bone surrounding the tooth were excluded in these models. Three types model(B, G and R model) were developed. B model was assumed perfect bonding between the restoration and cavity wall. Both compressive and tensile forces were distributed directly to the adjacent regions. G model(Gap Distance: 0.000001mm) was assumed the possibility of play at the interface simulated the lack of real bonding between the amalgam and cavity wall (enamel and dentin). When compression occurred along the interface, the forces were transferred to the adjacent regions. However, tensile forces perpendicular to the interface were excluded. R model was assumed non-connection between the restoration and cavity wall. No force was transferred to the adjacent regions. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed the displacement, von Mises stress, 1 and 2 direction normal stress and strain with FEM software ABAQUS Version 5.2 and hardware IRIS 4D/310 VGX Work-station. The results were as follows: 1. G model showed stress and strain patterns between Band R model. 2. B model and G model showed the bending phenomenon in the displacement. 3. R model showed the greatest amount of the displacement of the buccal cusp followed by G and B model in descending order. G model showed the greatest amount of the displacement of the lingual cusp followed by B and R model in descending order. 4. B model showed no change of the displacement as increasing depth and width of the cavity. G and R model showed greater displacement of the buccal cusp as increasing depth and width of the cavity, but no change in the displacement of the lingual cusp. 5. As increasing of the width of the cavity, stress and strain were not changed in B model. Stress and strain were increased on the distal marginal ridge and buccopulpal line angle in G and R model. The possibility of the tooth fracture was increased. 6. As increasing of the depth of the cavity, stress and strain were not changed in B and G model. Stress and strain were increased on the distal marginal ridge and buccopulpal line angle in R model. The possibility of the tooth fracture was increased.

• Clinics in Shoulder and Elbow
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• v.16 no.2
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• pp.130-134
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• 2013

A painful pseudoarthrosis will develop due to a delay in diagnosis and treatment, and surgical care is required. Treatment of pseudoarthrosis is really difficult because the acromion is a thin flat bone that is difficult to be fixed firmly. A 52-year-old woman with multiple trauma had an acromial fracture that was not detected until it had caused pain after ambulation. Open reduction and internal fixation with a variable angle locking compression plate for distal radius and autogenous iliac bone graft were performed. At nine months after the operation, there was partial tear in the supraspinatus tendon, and arthroscopic repair of the supraspinatus tendon was performed. At nine months after the operation, radiographs showed a complete union. At three months after tendon repair, the patient had excellent function of the shoulder. We have reported a case of a successful treatment of nonunion and pseudoarthrosis of acromial fracture that is difficult to be fixed.