• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1031-1036
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• 2007

Torsional vibration analysis is necessary at design stage to ensure the reliability of a system particularly when the driven machine is a reciprocating compressor. This paper contains the results of torsional vibration analysis and fatigue strength evaluation for 540 kW compressor driving motor. Torsional vibration analysis showed that the $2^{nd}$ torsional mode of the entire shaft system has the possibility of resonance with the $14^{th}$ order excitation of compressor and twin line frequency of motor at operating speed. Therefore, the analyses were required to ensure the structural reliability of the motor. The fatigue strength was evaluated for the shaft and inner fans using the results of forced vibration analysis. It is concluded that the motor has sufficient fatigue strength under normal operating condition.

• Structural Engineering and Mechanics
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• v.13 no.1
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• pp.91-101
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• 2002

During the last several years, research activity on non-tubular bonded joints has concentrated on the effects of normal stress, bending moments and shear. Nevertheless, in certain situations, the structure may be subjected to twisting moments, so that the evaluation of its dynamic behaviour to torsional vibrations becomes of great importance even though evaluations of such loading conditions is entirely lacking in the literature. The aim of this article is to show that torsional natural frequencies of the non-tubular joint can be evaluated by determining the roots of a determinantal equation, derived by taking advantage of some analytical results obtained in a previous paper dealing with the analysis of the state of stress in the adhesive. Numerical results related to clamped-free and clamped-clamped joints complete the article.

• Structural Engineering and Mechanics
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• v.25 no.2
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• pp.131-146
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• 2007

This paper presents the results of a study to show how the development of a crack alters the structural behavior of I-shaped steel beams and how this can be used to evaluate nondestructive evaluation techniques. The approach is based on changes in the dynamic behavior. An approximate finite element model for a cracked beam with I-shaped cross-section is developed based on a simplified fracture model. The model is then used to review different damage cases. Damage detection techniques are studied to determine their ability to identify the existence of the crack and to identify its location. The techniques studied are the coordinate modal assurance criterion, the modal flexibility, and the state and the slope arrays.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.744-747
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• 2004

This paper presents a strength evaluation of a tilling bogie frame for the Korean tilting train, The tilting bogies of the tilting train are subjected to different loading conditions compared with the bogie of the conventional railway vehicles because of the carboloy tilting on curves. We classified the load cases as two categories such as non-tilting case and tilting case. For the two categories. we have carried out structural analysis of the bogie frame to evaluate the strength of the frame. And then, we modified the shape and thickness for the weak areas of the bogie frame to ensure structural safety.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.10a
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• pp.105-112
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• 1996

A practical approach for the assessment of system reliability-based safety and load carring capacity under vehicle traffics is proposed for the realistic evaluation of safety and rating of cable-stayed bridges. A partial event tree analysis model incorporating major critical failure paths is suggested as a practical tool for the system reliability analysis and system reliability-based capacity rating. The proposed approach for the system reliability analysis and system reliability-based rating is applied to the safety assessment of the Jindo Bridge which is one of two existing cable-stayed bridges in Korea. The results of analyses at the system level based on the system reliability are compared with those at the element level.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.711-717
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• 2000

This paper presents an experimental study on evaluation of structural performance on corroded reinforced concrete columns under only axial load, combined axial load and lateral load. This test was carried on the twenty-six reinforced concrete columns with $150\times150\times800$mm size subjected to combined axial load and lateral load. Effects of key variables such as the corrosion level, the number of hoop, the corrosion of hoop are studied in this program. The results of this study show that the capacity of column axial force was decreased as corrosion level was increased, especially, rapid development was shown after 10% corrosion level and the maximum moment capacity of column was shown at corrosion level 1.2%, while rapid decrease was shown after 4.3% corrosion level. Also we found that influence of corrosion was decreased to number of tie bar was increased.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.103-104
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• 2010

There are two conflicting opinions about effect of confinement using High-Strength transverse reinforcement. This paper verifies evaluation of structural behavior of RC columns strengthened with high-strength steel bars by performing an experimental study of 15 large-scale column confined by high-strength transverse reinforcement tests.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.203-206
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• 2003

Using composite materials for the carbody of tilting train has many advantages such as manufacturing variety, specific high-strength ＆ stiffness characteristics, and long-life durability, but the strongest advantage could be the possibility of lightweight product. In the leading countries, the composite materials are used for the material fur drivers'cabs, interior/exterior equipments for railway train, and it is now developing the composite materials applied for the train carbody structure. In this paper, we conducted the evaluation of structural stability for the aluminum and composite carbody of the Korean Tilting Train express(TTX) with the service speed of 180km/h.

• Smart Structures and Systems
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• v.11 no.6
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• pp.569-587
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• 2013

This paper evaluates the closed loop performance of the reaching law based discrete sliding mode controller with multisensor data fusion (MSDF) in real time, by controlling the first two vibrating modes of a piezo actuated structure. The vibration is measured using two homogeneous piezo sensors. The states estimated from sensors output are fused. Four fusion algorithms are considered, whose output is used to control the structural vibration. The controller is designed using a model identified through linear Recursive Least Square (RLS) method, based on ARX model. Improved vibration suppression is achieved with fused data as compared to single sensor. The experimental evaluation of the closed loop performance of sliding mode controller with data fusion applied to piezo actuated structure is the contribution in this work.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.504-512
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• 2003

Simulation programs have been developed and used as an attempt to improve the accuracy of Non-Destructive Evaluation(NDE) techniques. The applicability of these programs is very limited, however, because it is difficult to describe the delicacy of the propagation of stress waves. To investigate the applicability of the finite element analysis for stress wave-based NDE techniques numerical simulation for Impact-Echo method and SASW method is performed. The numerical studies are performed to determine the essential parameters such as contact time of impact load, mesh size and time step size. These studies show that the choice of parameter is very important for improving the accuracy and confidence of the numerical procedure and, thereby, the applicability of the numerical analysis for stress wave-based NDE techniques