• Advances in materials Research
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• v.12 no.1
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• pp.15-29
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• 2023

In this paper, fracture analysis of a continuously inhomogeneous arch structure with two longitudinal cracks is developed in terms of the time-dependent strain energy release rate. The arch under consideration exhibits non-linear creep behavior. The cross-section of the arch is a rectangle. The material is continuously inhomogeneous along the thickness of the cross-section. The arch is loaded by two bending moments applied at its end sections. The mechanical behavior of the material is described by using a non-linear stress-strain-time relationship. The two longitudinal cracks are located symmetrically with respect to the mid-span of the arch. Due to the symmetry, only half of the arch is considered. Time-dependent solutions to strain energy release rate are obtained by analyzing the balance of the energy. For verification, time-dependent solutions to the strain energy release rate are derived also by considering the time-dependent complementary strain energy. The evolution of the strain energy release rate with the time is analyzed. The effects of material inhomogeneity, locations of the two cracks along the thickness of the arch and the magnitude of the external loading on the time-dependent strain energy release rate are evaluated.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.3
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• pp.28-36
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• 1986

This study was investigated the feasibility of AE application on in-process detection of tool fracture and chipping. Carbon steel SM45C workpiece with longitudinal slots was turned interruptedly on a lathe. AE RMS signal at tool fracture was observed and also the tangential force and the feed observed at the time of tool fracture, the levels of tangential force and the feed force at the time of fracture decrease considerably. In chipping, high level AE signal was observed but there were no changes of cutting force. Peak AE RMS squared is proportional to the area of tool fracture and resultant force. Fracture model of tool fracture is proposed as $V_{p}$ = $C_{1}$ $E_{1}$F(.DELTA. A)$_{0.5}$ and peak AE RMS shows strong correlation with the fracture parameter F(.DELTA.A)$^{0.5}$.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.59-68
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• 2010

In the present study, the deformation capacity of slender shear walls with thin web subject to inelastic deformation after flexural yielding was studied. Web-crushing and rebar-fracture were considered as the governing failure mechanisms of walls. To address the effect of the longitudinal elongation on web-crushing and rebar-fracture, the longitudinal elongation was predicted by using truss model analysis. The failure criteria by web-crushing and rebar-fracture were defined as a function of the longitudinal elongation. The proposed method was applied to 17 shear wall specimens with boundary columns, and the prediction results were compared with the test results. The results showed that proposed method predicted the maximum deformations and failure modes of the wall specimens with reasonable precision.

• Journal of Chest Surgery
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• v.49 no.5
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• pp.361-365
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• 2016

Background: Sternal fractures are relatively rare, and caused mainly by blunt anterior chest wall trauma. In most cases, sternal fractures are treated conservatively. However, if the patient exhibits problematic symptoms such as intractable chest wall pain or bony crepitus due to sternal instability, surgical correction is indicated. But no consensus exists regarding the most appropriate surgical method. We analyzed the results of surgical fixation in cases of sternal fracture in order to identify which surgical method led to the best outcomes. Methods: We retrospectively reviewed the medical records of patients with sternal fractures from December 2008 to December 2011, and found 19 patients who underwent open reduction and internal fixation of the sternum with a longitudinal plate (L-group) or a T-shaped plate (T-group). We investigated patients' characteristics, clinical details regarding each case of chest trauma, the presence of other associated injuries, the type of open reduction and fixation, whether a combined operation was performed, and postoperative complications. Results: Of the 19 patients, 10 patients (52.6%) were male, and their average age was 56.8 years (range, 32 to 82 years). Seven patients (36.8%) had isolated sternal fractures, while 12 (63.2%) had other associated injuries. Seven patients (36.8%) were in the L-group and 12 patients (63.2%) were in the T-group. Three patients in the L-group (42.9%) showed a loosening of the fixation. In all patients in the T-group, the fracture exhibited stable alignment. Conclusion: Open reduction and internal fixation with a T-shaped plate in sternal fractures is a safer and more efficient treatment method than treatment with a longitudinal plate, especially in patients with a severely displaced sternum or anterior flail chest, than a longitudinal plate.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.3
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• pp.313-317
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• 2000

Return of facial nerve function is important in patients with facial nerve paralysis by trauma. Sometimes, delay in diagnosis of facial nerve paralysis make recovery of facial nerve function difficult. Traumatic facial palsy mostly occur after temporal bone fracture in unilateral. Temporal bone fracture after head trauma are divided into the three group; longitudinal fracture, transverse fracture and mixed fracture. The most common symptoms are hearing impairment, bloody otorrhea, loss of consciousness and facial nerve paralysis. The early care of temporal bone fracture involves facial nerve paralysis. And there has been many discussion and study in the treatment of the immediate or delayed facial palsy ; examply, surgical approach, time and methods. We have managed a patient with unilateral facial nerve paralysis after longitudinal temporal bone fracture in mastoid process and conservative facial nerve decompression was performed. We have obtained good result and report this case with review of literatures.

• Journal of Korean Foot and Ankle Society
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• v.2 no.2
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• pp.71-75
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• 1998

The fact that, under similar training activities performed in the same environment, march fractures develop in only a certain percentage of the trainees indicates that intrinsic factors are affecting the prevalence of these fractures. Among these intrinsic factors, the relation between foot arch type and the occurance of march fractures was investigated in this study. From 1997 to 1998, at one infantry medical company of infantry corps in Korea, 15 march fracture patients were detected among infantry soldiers. Quantitative measures of the foot arch (longitudinal) structure of 15(30feet) march fracture patients were established and compared with those of 15(30feet) normal person. The results were as follows. 1. From the lateral X-ray film, three parameters (i.e. calcaneal angle, forefoot angle, height to length ratio)were defined to describe the structure of the longitudinal arch of the foot. 2. The mean value of the calcaneal angle of march fracture group and normal control group showed 16.4 degree, 20.5 degree respectively. The difference between two groups was statistically significant (P>0.006), but those of forefoot angle and height to length ratio were not. 3. In the calcaneal angle twenty-six feet(87%) of march fracture group were lower than 17 degrees but twenty-five feet(83%) of normal control group were more than 17 degrees. That is, march fracture were more prevalent in feet with low calcaneal angle. 4. In the low arch foot, the orthotic device might relieve the energy load carried by the foot, thus reducing the incidence of march fractures, and should be analyzed in further study.

• International Journal of Korean Welding Society
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• v.4 no.1
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• pp.46-52
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• 2004

To combine the mechanical advantages of ceramics with those of metals, one often uses both materials within one composite component. But, as known, they have different material properties and fracture behaviors. In this study, a four-point bending test is carried out on $Si_3N_4$ joined to ANSI 304L stainless steel with a Ti-Ag-Cu filler and a Cu interlayer at room temperature to evaluate their longitudinal strain behaviors. And, to detect localized strain, a couple of strain gages are pasted near the joint interfaces of the ceramic and metal sides. The normal strain rates are varied from $3.33{\times}10^5$ to $3.33{\times}10^{-1}s^{-1}$ Within this range, the experimental results showed that the four-point bending strength and the deflection of the interlayer increased with increasing the strain rate.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.47-52
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• 2008

The force transducer in the acceleration plant due to dynamic fracture is calibrated by dynamically using the stress pulses from a longitudinal bar. The bar is supported by two strings attached to the ceiling. The bar velocities before and after impact are measured and a full bridge at bar and transducer is formed by the four strain gauges. A transient recorder is used to store the stress pulse signals of force transducer and bar. For the first test series, three point bend test specimens can be chosen by means of test rig design and the inspection as sample experiment in this presented paper is sufficient for proving with the numerical simulation of the specimen model.

• Structural Engineering and Mechanics
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• v.9 no.6
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• pp.589-600
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• 2000

This paper attempts to provide a theoretical basis for the design of high-strength concrete columns in terms of the spacing of lateral reinforcement. In order to achieve this, important concepts had to be addressed such as the choice of a measure of ductile behaviour and a realistic high-strength concrete stress-strain model, as well as limiting factors such as longitudinal steel buckling and lateral steel fracture. A design method incorporating above factors are suggested in the paper. It is shown that both buckling of longitudinal steel and hoop fracture will not demand a reduction in spacing of lateral ties with increase in compressive strength of concrete.

• Journal of the Korean Wood Science and Technology
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• v.21 no.2
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• pp.15-22
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• 1993

This study was carried out to investigate the fracture criterion of glulam. The mixed mode fracture of glulam was investigated by means of single edge notched specimens with various crack inclination in the longitudinal-radial plane. While fracture of wood is not completely understood, the study on linear-elastic fracture mechanics is a rational and valuable tool for studying the strength behavior of glulam. The results are summarized as follows : 1. Glue line has no effect on fracture strength. 2. There is a definite interaction between fracture toughness $K_I$ and $K_{II}$ during the mixed mode fracture of glulam. Several criterions for mixed mode failure were compared. The criterion was expressed in the following form: $(\frac{K_I}{K_{IC}})^2+(\frac{K_{II}}{K_{IIC}})^2=1$ 3. As crack inclination increases, $K_{IC}$ value and $K_{IIC}$ value decreases. The equations relating crack angle to $K_{IC}$ and $K_{IIC}$, respectively, were obtained as follows; $K_{IC}$ = -77.42${\gamma}$+153.72 ($R^2$ = 0.78) $K_{IIC}$ = -9.17${\gamma}$+34.90 ($R^2$ = 0.48)