• International Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.1-3
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• 2021

This study proposed a specific preliminary structural design procedure of the main wing for a small scale WIG vehicle to meet the target weight of the system requirement. The high stiffness and strength Carbon-Epoxy material was used for lightness, and the foam sandwich type structure at the upper skin and the spar webs was adopted for improvement of structural stability. After structural design, wing joint part was designed. Through investigation on structural design result, design modification was performed. After design modification, even thought the designed wing weight was a little bit heavier than the target wing weight, the structural safety and stability of the final design feature was confirmed.

• International Journal of High-Rise Buildings
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• v.11 no.3
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• pp.207-219
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• 2022

During the structural design of urban over-track high-rise buildings, two problems are most likely encountered: the abrupt change of story stiffness between the podium and the upper towers, as well as the demand for train-induced vibration control. Traditional earthquake-resistant structures have to be particularly designed with transfer stories to meet the requirement of seismic control under earthquakes, and thus horizontal seismic isolation techniques are recommended to solve the transfer problem. The function of mitigating the vertical subway-induced vibration can be integrated into the isolation system including thick rubber bearings and 3D composite vibration control devices. Engineering project cases are presented in this paper for a more comprehensive understanding of the engineering practice and research frontiers of urban over-track high-rise buildings in China.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.6-7
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• 2020

The government of South Korea enacted Earthquake Recovery Plan Act in 2008. In order to meet the requirement of this law, the important buildings, such as schools, public offices and so on, are in the process of seismic retrofit. This paper introduces the experimental data about a non-retrofitted concrete column and retrofitted column with a bolt assembly type CFT(concrete-filled steel tube).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.187-192
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• 2016

While structures are designed within elastic range by other designs, plastic behavior of structures should be verified and controlled in order to prevent structural collapse by the earthquake resistant design. No Collapse Requirement for typical bridges is to avoid falling down of superstructure by way of plastic behavior of certain structural elements and to operate emergency vehicles after earthquake. Such plastic behavior is restricted to connections or pier columns and appropriate measures are required for each case. Earthquake Resistant Design part of Roadway Bridge Design Code provides design processes for Ductile Collapse Mechanism by forming plastic hinges at pier columns. Also for bridges with reinforced concrete piers ductility-based design processes are provided as an appendix constructing Brittle Collapse Mechanism with connection yielding. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected and No Collapse Design procedure considering both Ductile and Brittle Collapse Mechanism is proposed together with revisions required for the Earthquake Resistant Design part.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.509-516
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• 2013

In this paper, performance based design of coupling beam using non-linear static analysis is proposed considering probability distribution of flexural and shear strength in order to develop flexural hinge. This method considers post-yielding behavior of coupling beam and stress redistribution of system. It can verify the reduced effective stiffness to meet the current design requirement based on linear analysis. It also evaluates the lateral displacement under service load (un-factored wind load) properly. In addition, it can optimize the coupled shear wall system by taking stress redistribution between members into account. For a simplified 30-story building, non-linear static (push-over) analysis was performed and the structural behavior was checked at performance point and several displacement steps. Furthermore, system behavior according to the amount of reinforcement and depth of coupling beam was explored and compared each other.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.11-20
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• 2007

The study proposes the method to cancel the scallop to avoid fracture of the circumstance of the scallop at H shape column-to-beam connection and reinforce at beam flange two faces with the cover plates and rib. A total of four specimens were tested to enhance seismic performance of building structure by reducing the frequency of stress concentration and preventing the brittle fracture of scallop. For this purpose, four full-scale test specimens were made and loaded with quasi-static reversed cyclic loading. The main analytical parameters are panel-zone-strength ratio, yield strengths, initial stiffness, total plastic rotation, contribution of each element to total plastic rotation and energy dissipation capability. For the specimens tested under repeated loading, the experimental result was satisfied with seismic performance requirement as the Special Moment Frames (SMF). The analysis results show that all of the test specimens were found to have good performance to 4% story drift and satisfied the criteria for the plastic roation capacity of SMFs that is 0.03 rad. according to the 1997 AISC seismic provision.

• Earthquakes and Structures
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• v.18 no.6
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• pp.677-689
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• 2020

A building structural system of moment resisting frame (MRF) with concrete filled steel tubular (CFST) columns and wide flange H beams, is one of the most conveniently constructed structural systems. However, there were few studies on evaluating seismic performance of full-scale CFST columns under high axial compression. In addition, some existing famous design codes propose various limits of width-to-thickness ratio (B/t) for steel tubes of the ductile CFST composite members. This study was intended to investigate the seismic behavior of CFST columns under high axial load compression. Four full-scale square CFST column specimens with a B/t of 42 were carried out that were subjected to horizontal cyclic-reversal loads combined with constantly light, medium and high axial loads and with a linearly varied axial load, respectively. Test results revealed that shear strength and deformation capacity of the columns significantly decreased when the axial compression exceeded 0.35 times the nominal compression strength of a CFST column, P₀. It was obvious that the higher the axial compression, the lower both the shear strength and deformation capacities were, and the earlier and faster the shear strength degradation occurred. It was found as well that higher axial compressions resulted in larger initial lateral stiffness and faster degradation of post-yield lateral stiffness. Meanwhile, the lower axial compressions led to better energy dissipation capacities with larger cumulative energy. Moreover, the study implied that under axial compressions greater than 0.35P₀, the CFST column specimens with B/t limits recommended by AISC 360 (2016), ACI 318 (2014), AIJ (2008) and EC4 (2004) codes do not provide ultimate interstory drift ratio of more than 3% radian, and only the limit in ACI 318 (2014) code satisfies this requirement when axial compression does not exceed 0.35P₀.

• Archives of Plastic Surgery
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• v.49 no.5
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• pp.633-641
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• 2022

Introduction In chronic facial palsy, synkinetic muscle overactivity and shortening causes muscle stiffness resulting in reduced movement and functional activity. This article studies the role of multimodal therapy in improving outcomes. Methods Seventy-five facial palsy patients completed facial rehabilitation before being successfully discharged by the facial therapy team. The cohort was divided into four subgroups depending on the time of initial attendance post-onset. The requirement for facial therapy, chemodenervation, or surgery was assessed with East Grinstead Grade of Stiffness (EGGS). Outcomes were measured using the Facial Grading Scale (FGS), Facial Disability Index, House-Brackmann scores, and the Facial Clinimetric Evaluation scale. Results FGS composite scores significantly improved posttherapy (mean-standard deviation, 60.13 ± 23.24 vs. 79.9 ± 13.01; confidence interval, -24.51 to -14.66, p < 0.0001). Analysis of FGS subsets showed that synkinesis also reduced significantly (p < 0.0001). Increasingly, late clinical presentations were associated with patients requiring longer durations of chemodenervation treatment (p < 0.01), more chemodenervation episodes (p < 0.01), increased doses of botulinum toxin (p < 0.001), and having higher EGGS score (p < 0.001). Conclusions This study shows that multimodal facial rehabilitation in the management of facial palsy is effective, even in patients with chronically neglected synkinesis. In terms of the latency periods between facial palsy onset and treatment initiation, patients presenting later than 2 years were still responsive to multimodal treatment albeit to a lesser extent, which we postulate is due to increasing muscle contracture within their facial muscles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.39-45
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• 2002

The effect of reefing-line length and reefing methods on drag and inflated shape of the conical ribbon parachute were experimentally investigated. Tests were performed to determine reefing-line length of the parachute models, demonstrate aerodynamic adequacy of the reefing method, and confirmed that performance met the design requirement. The reefing ratio, drag-area ratio, was decreased in relation to the decrease in the length of the reefing-line and the stability of the parachute models was increased with reefing. The test results were compared with the avilable similar data. Fair to good agreement was obtained.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.101-106
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• 2000

As the rotational speed of optical disk drive is increasing nowadays, the reliability to vibration and shock becomes more important. For this, various of rubber vibration isolators are being developed by varying the shape and hardness. But it is difficult for the hardness of common used rubber to be lowered below Duro 30 degrees, and because of the shape complexity of rubber vibration isolator there are difficulties of analysis. Microcellular foamed vibration isolator has various cell densities and cell sizes, so it can vary the stiffness and damping coefficient. In addition, its hardness can be lowered below Duro 30 degrees. Axiomatic Approach is very useful design method for designing new product or new process. Axiomatic Approach's character is scientific and analytical method. In this paper, developing process of microcellular foamed vibration isolator for DVD is presented with Axiomatic Approach.