• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.248-253
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• 2003

Titanium alloy has widely been used as glasses rim material because it has high specific strength and also is light, harmless to men. But, we have little design data about the creep behaviors of the alloy. Therefore, in this study, an apparatus has been designed and built for conducting creep tests under constant load conditions. A series of creep tests on them have been performed to get the basic design data and life prediction of titanium products and we have gotten the following results. First, the stress exponents decrease as the test temperatures increase. Secondly, the creep activation energy gradually decreases as the stresses become bigger. Thirdly, the constant of Larson-Miller parameters on this alloy is estimated about 13. And last, the fractographs at the creep rupture show both the ductile and the brittle fracture according to the creep conditions.

• Investigative Magnetic Resonance Imaging
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• 제22권3호
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• pp.177-181
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• 2018

Intraperitoneal metastatic hepatocellular carcinoma (HCC) is uncommon. Although rare, it can spontaneously rupture and cause hemoperitoneum similar to primary HCC in the liver. We present a case of intraperitoneal metastatic HCC that had spontaneously ruptured and appeared as an irregularly margined hemorrhagic mass with T1 high and T2 dark signal intensities on magnetic resonance imaging. Ruptured HCC is a life-threatening emergency with high mortality rate. Spontaneously ruptured intraperitoneal metastatic HCC should be considered if a patient with a history of HCC presents with acute abdomen, although rare.

• Journal of Chest Surgery
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• 제27권1호
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• pp.43-47
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• 1994

Prompt recognition and proper treatment of esophageal perforation or rupture may ax~ert death or minimize complications. We have experienced sixteen patients of esophageal perforation at the department of thoracic and cardiovascular surgery, Hallym Medical college during the period fromJan. 1986 to Sep. 1993. The ratio between male and female patient was 13:3 and their age ranged from 23 years to 67 years old. The major cause of esophageal perforations was spontaneous rupture in 7 cases[45%], surgical trauma in 2 cases[12%], instrumental trauma in 2 cases[12%], and others in 5 cases[31%]. The common site of esophageal perforation was in the lower third portion of the esophagus[10 cases, 62%]. The most consistent symptom of esophageal perforation was chest pain in 11 cases, temperature elevation within a few hours was 9 cases.Contrast roentgenographic studies demonstrated the perforation in all but 2 of the 16 patients. The frequent complications of esophageal perforation were empyema in 7 cases[45 %] and mediastinitis in 2 cases[12%]. fourteen patients had suture closure and drainage with 2 deaths, and 2 patient received only drainage procedures. The mortality rate was 12%[2 cases] and cause of death was sepsis and aortic rupture.

• Steel and Composite Structures
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• 제48권1호
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• pp.43-57
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• 2023

The impacts of waste tire rubber (WTR) on the bending conduct of reinforced concrete beams (RCBs) are investigated in visualization of experimental tests and 3D finite element model (FEM) using both ANSYS and SAP2000. Several WTR rates are used in total 4 various full scale RCBs to observe the impact of WTR rate on the rupture and bending conduct of RCBs. For this purpose, the volumetric ratios (Vf) of WTR were chosen to change to 0%, 2.5%, 5% and 7.5% in the whole concrete. In relation to experimental test consequences, bending and rupture behaviors of the RCBs are observed. The best performance among the beams was observed in the beams with 2.5% WTR. Furthermore, as stated by test consequences, it is noticed that while WTR rate in the RCBs is improved, max. bending in the RCBs rises. For test consequences, it is clearly recognized as WTR rate in the RCB mixture is improved from 0% to 2.5%, deformation value in the RCB remarkably rises from 3.89 cm to 7.69 cm. This consequence is markedly recognized that WTR rates have a favorable result on deformation values in the RCBs. Furthermore, experimental tests are compared to 3D FEM consequences via using ANSYS software. In the ANSYS, special element types are formed and nonlinear multilinear misses plasticity material model and bilinear misses plasticity material model are chosen for concrete and compression and tension elements. As a consequence, it is noticed that each WTR rates in the RCBs mixture have dissimilar bending and rupture impacts on the RCBs. Then, to observe the impacts of WTR rate on the constructions under near-fault ground motions, a reinforced-concrete building was modelled via using SAP2000 software using 3-D model of the construction to complete nonlinear static analysis. Beam, column, steel haunch elements are modeled as nonlinear frame elements. Consequently, the seismic impacts of WTR rate on the lateral motions of each floor are obviously investigated particularly. Considering reduction in weight of structure and capacity of the members with using waste tire rubber, 2.5% of WTR resulted in the best performance while the construction is subjected to near fault earthquakes. Moreover, it is noticeably recognized that WTR rate has opposing influences on the seismic displacement behavior of the RC constructions.

• Design & Manufacturing
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• 제2권6호
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• pp.43-48
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• 2008

Magnesium alloys have given high attention to the industry of light-weigh as automobile and electronics with aluminium, titanium and composite alloys due to their high strength, low specific density and good damping characteristics. But the magnesium contained structures under high temperature have the problems related to creep deformation and rupture life, which is a reason of developing the new material against creep deformation to use them safely. The purpose of this study is to predict the creep deformation mechanism and rupture time of AZ31 magnesium alloy. For this, creep tests of AZ31 magnesium alloy were done under constant creep load and temperature with the equipment including automatic temperature controller with acquisition computer. The apparent activation energy Qc, the applied stress exponent n and rupture life have been determined over the temperature range below 0.5Tm and stress range of 109~187MPa, respectively, in order to investigate the creep behavior. AZ31 Magnesium alloy identify the activation energy for creep deformation and the stress dependence to creep rate at below 0.5Tm, and then investigate the mechanism for creep deformation and creep rupture life of AZ31 Magnesium alloy.

• Archives of Plastic Surgery
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• 제42권1호
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• pp.4-10
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• 2015

Mammary implants marketed by Poly Implant Proth$\grave{e}$se (PIP) were found to contain industrial grade silicone and this caused heightened anxiety and extensive publicity regarding their safety in humans. These implants were used in a large number of patients worldwide for augmentation or breast reconstruction. We reviewed articles identified by searches of Medline, PubMed, Embase, and Google Scholar databases up to May 2014 using the terms: "PIP", "Poly Implant Proth$\grave{e}$se", "breast implants" and "augmentation mammoplasty" "siloxanes" or "silicone". In addition the websites of regulating bodies in Europe, USA, and Australia were searched for reports related to PIP mammary implants. PIP mammary implants are more likely to rupture than other implants and can cause adverse effects in the short to the medium term related to the symptoms of rupture such as pain, lumps in the breast and axilla and anxiety. Based on peer-reviewed published studies we have calculated an overall rupture rate of 14.5% (383/2,635) for PIP implants. However, there is no evidence that PIP implant rupture causes long-term adverse health effects in humans so far. Silicone lymphadenopathy represents a foreign body reaction and should be treated conservatively. The long-term adverse effects usually arise from inappropriate extensive surgery, such as axillary lymph node dissection or extensive resection of breast tissue due to silicone leakage.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.153-158
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• 2005

Titanium alloy has widely been used as material for automotive parts because it has high specific strength. It is also light and harmless to human body. But, we have little design data about the creep behaviors of the alloy. Therefore, in this study, creep tests under four constant stress conditions have been conducted with low different temperature conditions. A series of creep tests had been performed to get the basic design data and life prediction of titanium products and we have gotten the fallowing results. First, the stress exponents decrease as the test temperatures increased. Secondly, the creep activation energy gradually decrease as the stresses became bigger. Thirdly, the constant of Larson-Miller parameter on this alloy was estimated as about 7.5. And for the last, the fractographs at the creep rupture showed the ductile fracture due to the intergranullar rupture.

• 한국재료학회지
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• 제31권5호
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• pp.255-263
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• 2021

P91 steel has been a highly researched material because of its applicability for high-temperature applications. Considerable efforts have been made to produce experimental creep data and develop models for creep life prediction. As creep tests are expensive and difficult to conduct, it is vital to develop authenticated empirical methods from experimental results that can be utilized for better understanding of creep behavior and can be incorporated into computational models for reliable prediction of creep life. In this research, a series of creep rupture tests are performed on the P91 specimens within a stress range of 155 MPa to 200 MPa and temperature range of 640 ℃ (913 K) to 675 ℃ (948 K). The microstructure, hardness, and fracture surfaces of the specimens are investigated. To analyze the results of the creep rupture tests at a macro level, a parameter called creep work density is derived. Then, the relationships between various creep parameters such as strain, strain rate, time to rupture, creep damage tolerance factor, and creep work density are investigated, and various empirical equations are obtained.

• Journal of Trauma and Injury
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• 제36권3호
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• pp.281-285
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• 2023

Traumatic uterine rupture is uncommon but can be fatal and life-threatening for both the mother and infant. In addition to complications caused by trauma itself, such as pelvic fracture, gestational complications such as placental abruption, abortion, premature labor, rupture of membranes, maternal death, and stillbirth can occur. In particular, fetuses have been reported to have a high mortality rate in cases of traumatic uterine rupture. A 35-year-old pregnant female patient fell from the fourth floor and was admitted to our trauma center. We observed large hemoperitoneum, pelvic fractures, and spleen laceration, and the fetus was presumed to be located outside the uterus. The pregnant woman was hemodynamically unstable. Although the fetus was stillborn, angioembolization and surgical treatment were properly performed through collaboration with an interventional radiologist, obstetrician, and trauma surgeons. After two orthopedic operations, the patient was discharged after 34 days. This case report suggests the importance of a multidisciplinary approach in the treatment of pregnant trauma patients.

• Journal of Welding and Joining
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• 제10권4호
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• pp.230-239
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• 1992

The specimens of two base metals and material friction-welded with hetrogeneous steels of SM40C and STS304 have been prepared and the characteristics of rupture and crack propagation of them have been examined. In the friction-welded material, the width of HAZ is 3.0mm for STS304 and 3.4mm for SM40C. The hardness distribution in HAZ of SM40C is decreased gradually as being getting off interface, but that in HAZ of STS304 is decreased remarkedly and the value of hardness becomes a little lower than that of the base metal in region of 1mm from interface and becomes a little higher than that of the base metal. The tensile strength of the friction-welded material appeared a little lower than that of the base metal and rupture by tensile load is developed in HAZ of STS304 and the position of rupture is at region of low hardness(1mm from interface). The crack propagation rates(da/dN) in both HAZ of the friction-welded material are a little higher than those in both base metals, but the difference are less except for the case of SM45C in low .DELTA. K value. It has been ascertained that the crack in the interface propagates selectively along the HAZ of SM40C and consequently the crack propagation rate is almost similar to that in the HAZ of SM40C.