• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.357-363
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• 2022

In this study, in order to develop an non-slip metal grating, the stability of the grating according to the span of the grating and the gap and height of the bearing bar was evaluated. The optimal shape design of the grating was performed using the results of determining the stability of the grating. The purpose of this study is to determine the stability according to the spacing and height of the bearing bar by applying the design pressure at the design stage to develop the anti-skid grating, and to design the optimal shape for cost reduction. In the optimal design, the target variable was set as the mass, and the optimal design of the grating was performed based on about 20%. Regardless of the height of the bearing bar of the grating, the stress and deformation of the span and the grating showed a proportional tendency to each other, and it was found that the stress decreased as the height of the bearing bar increased. Based on the structural analysis results, an optimal design was performed using mass as the objective variable, and the existing 2mm thickness was changed to 1.6mm, reducing the mass by about 19%. The stress increased by about 4.4% compared to the maximum stress of the existing grating, but the minimum safety factor was 3.1, indicating that the optimally designed grating was stable.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1477-1485
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• 1996

Since the spindle bearing systme is the main source of the total cutting point compliance of machine tool structures, in this work, the static and dynamic characteristics of the spndle bearing systme driven by the gear located on the bearing span were investigated using analytical and finite elemtn methods to improve the performance of the spindle bearing system. Based on the theretical results, a specially designed prototype spindle bvearing systme was manufactured. Using the manufactured spindle bearing system, the static and dynamic characteristics were measured. From the comparison of the experimental results with the theoretical results, it was found that the finite elemetn method predicted well the static and dynamic characteristics of the spindle bearing system.

• Structural Monitoring and Maintenance
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• v.5 no.1
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• pp.93-110
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• 2018

In order to provide a novel strategy for long-span bridge health monitoring system design, this paper proposes a novel ultimate bearing capacity ratios based bridge internal force monitoring design method. The bridge ultimate bearing capacity analysis theories are briefly described. Then, based on the ultimate bearing capacity of the structural component, the component ultimate bearing capacity ratio, the uniformity of ultimate bearing capacity ratio, and the reference of component ultimate bearing capacity ratio are defined. Based on the defined indices, the high bearing components can then be found, and the internal force monitoring system can be designed. Finally, the proposed method is applied to the bridge health monitoring system design of the second highway bridge of Wuhu Yangtze river. Through the ultimate bearing capacity analysis of the bridge in eight load conditions, the high bearing components are found based on the proposed method. The bridge internal force monitoring system is then preliminary designed. The results show that the proposed method can provide quantitative criteria for sensors layout. The monitoring components based on the proposed method are consistent with the actual failure process of the bridge, and can reduce the monitoring of low bearing components. For the second highway bridge of Wuhu Yangtze river, only 59 components are designed to be monitored their internal forces. Therefore, the bridge internal force monitoring system based on the ultimate bearing capacity ratio can decrease the number of monitored components and the cost of the whole monitoring system.

• Tribology and Lubricants
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• v.10 no.1
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• pp.62-68
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• 1994

The analysis of statically indeterminate bearing-shaft system was investigated. The moment loads and misalignment angles which were induced in the ball bearings were determined, and the influence of span length of this system on the moment loads and fatigue lives was identified. The sliding and spinning speeds between balls and raceways which affected the performance of ball bearing evaluated. The equation to estimate the cage speed of ball bearing under moment loads was proposed. This equation had been verified by the test results of measuring of cage speed, which was useful to the prediction of ball bearing under moment loads.

• Structural Engineering and Mechanics
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• v.77 no.4
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• pp.559-569
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• 2021

This study was conducted to investigate the residual bearing capacity of steel-concrete composite beams under high-cycle fatigue loading through experiments and theoretical analysis. Six test beams with stud connectors were designed and fabricated for static, complete fatigue, and partial fatigue tests. The failure modes and the degradation of several mechanical performance indicators of the composite beams under high-cycle fatigue loading were analyzed. A calculation method for the residual bearing capacity of the composite beams after certain quantities of cyclic loading cycles was established by introducing nonlinear fatigue damage models for concrete, steel beam, and shear connectors beginning with the material residual strength attenuation process. The results show that the failure mode of the composite beams under the given fatigue load appears to be primarily affected by the number of cycles. As the number of fatigue loadings increases, the failure mode transforms from mid-span concrete crushing to stud cutting. The bearing capacity of a 3.0-m span composite beam after two million fatigue cycles is degraded by 30.7% due to premature failure of the stud. The calculated values of the residual bearing capacity method of the composite beam established in this paper agree well with the test values, which indicates that the model is feasibly applicable.

• Structural Engineering and Mechanics
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• v.61 no.5
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• pp.645-655
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• 2017

To determine the seismic applicability of a long-span railway concrete upper-deck arch bridge with concrete-filled steel-tube (CFST) rigid skeleton ribs, some fundamental principles and seismic approaches for long-span bridges are investigated to update the design methods in the current Code for Seismic Design of Railway Engineering of China. Ductile and mixed isolation design are investigated respectively to compare the structural seismic performances. The flexural moment and plastic rotation demands and capacities are quantified to assess the seismic status of the ductile components. A kind of triple friction pendulum (TFP) system and lead-plug rubber bearing are applied simultaneously to regularize the structural seismic demands. The numerical analysis shows that the current ductile layout with continuous rigid frame approaching spans should be strengthened to satisfy the demands of rare earthquakes. However, the mixed isolation design embodies excellent seismic performances for the continuous girder approaching span of this railway arch bridge.

• YAKHAK HOEJI
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• v.45 no.6
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• pp.641-649
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• 2001

In this study, the antitumor activities were investigated using $\beta$-lmmunan, a proteoglycan obtained from cultured mycelia of the IY009 strain of Ganoderma lucidum belonging to basidiomycetes. The result showed the significant effect of cytotoxicity test against murine sarcoma 180 and murine lymphocytic leukemia L1210 using immunized macrophage cultures by $\beta$-lmmunan. When intraperitoneally injected at 40 mg/kg/day daily for 10 days, $\beta$-lmmunan inhibited the growth of sarcoma 180 solid tumor in ICR mice by 88.8% (p<0.05). It was also observed that $\beta$-lmmunan increased life span by 85.2% (p<0.01) after treatment of 100 mg/kg/day in BDF1 mice bearing lymphocytic leukemia L1210. And combination therapy with cisplatin (dosage: 4 mg/kg) increased life span by 140.4% (p<0.05) after treatment of 100 mg/kg/day daily in BDF1 mice bearing lymphocytic leukemia L1210.

• Earthquakes and Structures
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• v.16 no.6
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• pp.665-677
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• 2019

This study utilizes large-scale shake table test to investigate the seismic performance of an isolated bridge with lead rubber bearings crossing an active fault. Two transverse restraining systems with and without shear keys are tested by applying spatially varying ground motions. It is shown that the near-fault span exhibits larger bearing displacement than the crossing-fault span. Bridge piers away from the fault rupture are more vulnerable than those adjacent to the fault rupture by attracting more seismic demand. It is also verified that the shear keys are effective in restraining the bearing displacement on the near-fault span, particularly under the large permanent ground displacement.

• Structural Engineering and Mechanics
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• v.42 no.6
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• pp.799-813
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• 2012

Five two-span reinforced concrete (RC) slabs and seven two-span RC beams were tested under the ISO 834 standard fire with different durations. CFRP strengthening was then applied to some of the specimens after the damaged concrete was removed from the specimens and replaced with polymer mortar. All the specimens were loaded to failure to investigate the influence of fire-damage and the effectiveness of strengthening methods. Test results indicated that the flexural capacities of specimens decrease with the fire duration increases. Moreover, fire exposure had more significant effect on the flexural rigidity than on the bearing capacity of the specimens. After rehabilitation, the bearing capacities of specimens reached or even exceeded that of the reference RC specimen, and the strengthening methods seemed to have limited effect on flexural rigidity recovery. From the analysis of moment redistribution of tested beams, elevated temperature is found having different impacts on sagging moment region and hogging moment region. The damage of RC continuous member is definitely a comprehensive response of different regions.

• Advances in Traditional Medicine
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• v.7 no.4
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• pp.426-435
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• 2007

The present study was designed to determine the antitumor and antioxidant properties of methanol extract from the root of Galega purpurea (Papilionaceae) (MEGP) against Ehrlich Ascites Carcinoma (EAC) bearing Swiss albino mice. Acute and short-term toxicity studies were performed initially in order to ascertain the safety of MEGP. The effect of MEGP on the growth of transplantable murine tumor, life span of EAC bearing hosts and simultaneous alterations in the hematological profile and liver biochemical parameters (lipid peroxidation, antioxidant enzymes) were estimated. The MEGP showed decrease in tumor volume, packed cell volume and viable cell count and increases the nonviable cell count and mean survival time thereby increasing life span of EAC tumor bearing mice. Hematological profile reverted to more or less normal levels in extract treated mice. Treatment with MEGP decreased the levels of lipid peroxidation and increased the levels of glutathione, superoxide dismutase and catalase. The results suggested that the methanol extract of Galega purpurea root exhibited antitumor effect by modulating lipid peroxidation and augmenting antioxidant defense system in EAC bearing mice.