• Title/Summary/Keyword: force-time history method

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Fashion Design Study by Whole Cut Way (Whole cut에 의한 패션디자인 연구)

  • Park, You Shin
    • Journal of Fashion Business
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    • v.19 no.5
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    • pp.199-212
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    • 2015
  • Environmentally-friendly whole-cut designs can minimize carbon dioxide emissions which are harmful to the earth, and reduce energy, labor force and time in cutting or sewing clothes. The design and way of wearing clothing will be investigated by classifying whole-cut clothing appearing in the history of costume and past traditional outfits such as Drapery, a Pancho, Tunic, or Loincloth. According to the results from the analysis of whole-cut methods applied in design, they were classified as follows: whole-cut, utilizing square-panels as is, pleats, smoking, lip band, origami, cutting way, and subtraction-cutting whole-cut design. The whole-cut design utilizing square panel as it is can minimize the waste of energy and material but can also maximize the possibility of circulation by recycling. In utilizing an all square panel, it broke away from the existing whole-cut in the western pattern, namely, the pattern of clothes clinging to the body, and was found to have new aesthetic value with a new approach. Due to the whole-cut method having a restriction in the use of dart and line cutting in its designing process, there were only designs that did not show the body line, such as designs clinging to the body. Therefore we developed a design similar to those that cling to the body by whole-cut, In addition, the work produced was with high efficiency and variability, which produces simple designs but can be worn in a variety of ways.

Optimization of modal load pattern for pushover analysis of building structures

  • Shayanfar, Mohsen Ali;Ashoory, Mansoor;Bakhshpoori, Taha;Farhadi, Basir
    • Structural Engineering and Mechanics
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    • v.47 no.1
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    • pp.119-129
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    • 2013
  • Nonlinear Static Procedures (NSPs) have been developed as a practical tool to estimate the seismic demand of structures. Several researches have accomplished to minimize errors of NSPs, namely pushover procedures, in the Nonlinear Time History Analysis (NTHA), as the most exact method. The most important issue in a typical pushover procedure is the pattern and technique of loading which are extracted based on structural dynamic fundamentals. In this paper, the coefficients of modal force combination is focused involving a meta-heuristic optimization algorithm to find the optimum load pattern which results in a response with minimum amount of errors in comparison to the NTHA counterpart. Other parameters of the problem are based on the FEMA recommendations for pushover analysis of building structures. The proposed approach is implemented on a high-rise 20 storey concrete moment resisting frame under three earthquake records. In order to demonstrate the effectiveness and robustness of the studied procedure the results are presented beside other well-known pushover methods such as MPA and the FEMA procedures, and the results show the efficiency of the proposed load patterns.

Axial impact behavior of confined concrete filled square steel tubes using fiber reinforced polymer

  • Zhang, Yitian;Shan, Bo;Kang, Thomas H.K.;Xiao, Yan
    • Steel and Composite Structures
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    • v.38 no.2
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    • pp.165-176
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    • 2021
  • Existing research on confined concrete filled steel tubular (CCFT) columns has been mainly focused on static or cyclic loading. In this paper, square section CCFT and CFT columns were tested under both static and impact loading, using a 10,000 kN capacity compression test machine and a drop weight testing equipment. Research parameters included bonded and unbonded fiber reinforced polymer (FRP) wraps, with carbon, basalt and glass FRPs (or CFRP, BFRP, and GFRP), respectively. Time history curves for impact force and steel strain observed are discussed in detail. Experimental results show that the failure modes of specimens under impact testing were characterized by local buckling of the steel tube and cracking at the corners, for both CCFT and CFT columns, similar to those under static loading. For both static and impact loading, the FRP wraps could improve the behavior and increase the loading capacity. To analyze the dynamic behavior of the composite columns, a finite element, FE, model was established in LS-DYNA. A simplified method that is compared favorably with test results is also proposed to predict the impact load capacity of square CCFT columns.

Effect of connection stiffness on the earthquake-induced progressive collapse

  • Ali, Seyedkazemi;Mohammad Motamedi, Hour
    • Earthquakes and Structures
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    • v.23 no.6
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    • pp.503-515
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    • 2022
  • Global or partial damage to a structure due to the failure of gravity or lateral load-bearing elements is called progressive collapse. In the present study, the alternate load path (ALP) method introduced by GSA and UFC 4-023-03 guidelines is used to evaluate the progressive collapse in special steel moment-resisting frame (SMRF) buildings. It was assumed that the progressive collapse is due to the earthquake force and its effects after the removal of the elements still remain on the structures. Therefore, nonlinear dynamic time history analysis employing 7 earthquake records is used to investigate this phenomenon. Internal and external column removal scenarios are investigated and the stiffness of the connections is changed from semi-rigid to rigid. The results of the analysis performed in the OpenSees program show that the loss of the bearing capacity of an exterior column due to a seismic event and the occurrence of progressive collapse can increase the inter-story drift of the structure with semi-rigid connections by more than 50% and make the structure unable to satisfy the life safety performance level. Furthermore, connection stiffness severely affects the redistribution of forces and moments in the adjacent elements of the removed column.

Reliability Analysis Offshore Wind Turbine Support Structure Under Extreme Ocean Environmental Loads (극한 해양 환경하중을 고려한 해상풍력터빈 지지구조물의 신뢰성 해석)

  • Lee, Sang Geun;Kim, Dong Hyawn
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.26 no.1
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    • pp.33-40
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    • 2014
  • Reliability analysis of jacket type offshore wind turbine (OWT) support structure under extreme ocean environmental loads was performed. Limit state function (LSF) of OWF support structure is defined by using structural dynamic response at mud-line. Then, the dynamic response is expressed as the static response multiplied by dynamic response factor (DRF). Probabilistic distribution of DRF is found from response time history under design significant wave load. Band limited beta distribution is used for internal friction angle of ground soil. Wind load is obtained in the form of thrust force from commercial code called GH_Bladed and then, applied to tower hub as random load. In a numerical example, the response surface method (RSM) is used to express LSF of jacket type support structure for 5MW OWF. Reliability index is found using first order reliability method (FORM).

A Documentational Study on the Development of Chi-Kung-Hak (기공학(氣功學) 발달(發達)에 관한 문헌적(文獻的) 연구(硏究))

  • Kim Woo-Ho;Hong Won-Sik
    • Journal of Korean Medical Ki-Gong Academy
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    • v.1 no.1
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    • pp.13-59
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    • 1996
  • Dep. of Classics &Medical History, College of Oriental Medicint, Kyung Hee University Today, many people are more interested Today, many people are more interested in preventing the disease than curing it. Chi-Kung(氣功) is the way of Life-Cultivation(養生法) peculiar to the orient, it is reported in china that Chi-Kung has an excellent curative value not only in curing the disease but also in preventing it. But the full-scale study of Chi-Kung is not be made up to now in Korea, so I studied the developmental history of chinese Chi-Kung through the oriental medical books. From this study, I reached the following conclusions; 1. Chi-Kung is naturally derived from the self-preservation instinct to adapt oneself to circumstances of the nature, but in the investigation from the documentational records, it is originated in the treatment method of the Sam-Huang-O-Jae(三皇五帝) period to cure the abnormal circulation of the vital force and blood caused by damp(濕). 2. As the principle and the method of the Life-Cultivation of the Chun-Chu-Jeon-Kook(春秋戰國) period were recorded in Huang-Jae-Nai-Gyung(黃帝內經) detailly and the remedy examples by ancient Chi-Kung such as Tao-Yin(導引), Haeng-Chi(行氣) were presented, we considered that theoretical basis of the development of Life-cultivation and Chi-Kung study was furnished in that period. 3. A famous doctor, Hwa-Ta(華引) lived in Han dynasty, researched the theory and practice of Tao-Yin transmitted from the former generations, as that result, he formed a kind of medical, gymnastics what is called O-Keum-Hi(五禽?). It is considered that 'O-Keum-Hi' is a Tao-Yin method developed more practically and systemetically than the Tao-Yin appeared in the 'Jang-Ja'(莊子) or 'Hoy-Nam-Ja'(淮南子). 4. In Wui-Jin-Nambook-Jo(魏曺南北朝) periods, the contents of Chi-Kung were more abundant under the influence of Buddhism(佛敎) and Taoism(道敎). Galhong(葛洪), the author of 'Po-Bak-Ja'(抱朴子) arranged the ancient Chi-Kung method systematically first of all, Tao-Goeng-Gyung, the author of 'Yang-Seong-Yeun-Myung-Rok'(養性延命錄) recorded the 'Yook-Ja-Geul'(六字訣) first time. 5. There is a new development of Chi-Kung therapy in Soo-Tang-Odae(隋唐五代) periods, especially So-Won-Bang(巢元方), the author of 'Jey-Bang-Won-Hwu-Ron' collected almost all of the Chi-Kung method, for curing the disease formed before Soo(隋) period. From that fact, we supposed that Chi-Kung was utilized more widely in curing the disease. 6. 'So-Ju-Cheon-Hwa-Hu-Peob'(小周天火候法) was adopted as the best orthodox approach under the influence of Nae-Tan-Taoist(道敎內丹學波) in Song-Keum-Won(宋金元) periods, especially in the song dynasty, 'Pal-Dan-Geum'(八段錦) was appearde and assignment of six-Chi(六氣) for bowel and viscera in the 'Yook-Ja-Geul'(六字訣) was decided firmly, that is to say Lung-Si(肺-?), Heart-Kha(心-呵), Spleen-Hoa(脾-呼), liver-Hoe(肝-噓), Kidney-chui(賢-吹), Three-Burner-shi(三焦-?). 7. In Myung-Cheong(明淸) periods, The general practitioner applied the principle of 'Byun-Jeng-Ron-Chi(辨證論治) to the Chi-Kung field, and after Myung dynasty the style of doing 'Yook-Ja-Gyel'(六字訣) was developed to the moving style. 8. Today, in china, the study on the Chi-Kyung is being progressed constantly under the positive assistance of government, Chi-Kung-Hak(氣功學) has taking its place as a branch of study step by step. It is considered that the establishment of Chi-Kung-Hak Classroom(氣功學敎室) and Medical Chi-Kung Center(氣功療法室) for special and systematic research are needed, at the same time the settlement of institutional system for training the Chi-Kung technician(氣功師) is also needed.

Seismic and Blast Design of Industrial Concrete Structures with Precast Intermediate Shear Wall System (프리캐스트 중간전단벽 시스템이 사용된 콘크리트 산업 시설물의 내진 및 방폭설계)

  • Lee, Won-Jun;Kim, Min-Su;Kim, Seon-hoon;Lee, Deuckhang
    • Journal of the Earthquake Engineering Society of Korea
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    • v.28 no.2
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    • pp.93-101
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    • 2024
  • Code-compliant seismic design should be essentially applied to realize the so-called emulative performance of precast concrete (PC) lateral force-resisting systems, and this study developed simple procedures to design precast industrial buildings with intermediate precast bearing wall systems considering both the effect of seismic and blast loads. Seismic design provisions specified in ACI 318 and ASCE 7 can be directly adopted, for which the so-called 1.5Sy condition is addressed in PC wall-to-wall and wall-to-base connections. Various coupling options were considered and addressed in the seismic design of wall-to-wall connections for the longitudinal and transverse design directions to secure optimized performance and better economic feasibility. On the other hand, two possible methods were adopted in blast analysis: 1) Equivalent static analysis (ESA) based on the simplified graphic method and 2) Incremental dynamic time-history analysis (IDTHA). The ESA is physically austere to use in practice for a typical industrial PC-bearing wall system. Still, it showed an overestimating trend in terms of the lateral deformation. The coupling action between precast wall segments appears to be inevitably required due to substantially large blast loads compared to seismic loads with increasing blast risk levels. Even with the coupled-precast shear walls, the design outcome obtained from the ESA method might not be entirely satisfactory to the drift criteria presented by the ASCE Blast Design Manual. This drawback can be overcome by addressing the IDTHA method, where all the design criteria were fully satisfied with precast shear walls' non-coupling and group-coupling strength, where each individual or grouped shear fence was designed to possess 1.5Sy for the seismic design.

Multi-dimensional wind vibration coefficients under suction for ultra-large cooling towers considering ventilation rates of louvers

  • Ke, S.T.;Du, L.Y.;Ge, Y.J.;Tamura, Y.
    • Structural Engineering and Mechanics
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    • v.66 no.2
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    • pp.273-283
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    • 2018
  • Currently, the dynamic amplification effect of suction is described using the wind vibration coefficient (WVC) of external loads. In other words, it is proposed that the fluctuating characteristics of suction are equivalent to external loads. This is, however, not generally valid. Meanwhile, the effects of the ventilation rate of louver on suction and its WV are considered. To systematically analyze the effects of the ventilation rate of louver on the multi-dimensional WVC of ultra-large cooling towers under suctions, the 210 m ultra-large cooling tower under construction was studied. First, simultaneous rigid pressure measurement wind tunnel tests were executed to obtain the time history of fluctuating wind loads on the external surface and the internal surface of the cooling tower at different ventilation rates (0%, 15%, 30%, and 100%). Based on that, the average values and distributions of fluctuating wind pressures on external and internal surfaces were obtained and compared with each other; a tower/pillar/circular foundation integrated simulation model was developed using the finite element method and complete transient time domain dynamics of external loads and four different suctions of this cooling tower were calculated. Moreover, 1D, 2D, and 3D distributions of WVCs under external loads and suctions at different ventilation rates were obtained and compared with each other. The WVCs of the cooling tower corresponding to four typical response targets (i.e., radial displacement, meridional force, Von Mises stress, and circumferential bending moment) were discussed. Value determination and 2D evaluation of the WVCs of external loads and suctions of this large cooling tower at different ventilation rates were proposed. This study provides references to precise prediction and value determination of WVC of ultra-large cooling towers.

A Documentational Study on the Development of Chi-Kung-Hak (기공학(氣功學) 발달(發達)에 관한 문헌적(文獻的) 연구(硏究))

  • Kim, Woo Ho;Hong, Won Sik
    • Journal of Korean Medical classics
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    • v.4
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    • pp.19-73
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    • 1990
  • Today, many people are more interested in preventing the disease than curing it. Chi-Kung (氣功) is the way of Life-Cultivation (養生法) peculiar to the orient, it is reported in china that Chi-Kung has an excellent curative value not only in curing the disease but also in preventing it. But the full-scale study of Chi-Kung is not be made up to now in Korea, so I studied the developmental history of chinese Chi-Kung through the oriental medical books. From this study, I reached the following conclusions ; 1. Chi-Kung is naturally derived from the self-preservation instinct to adapt oneself to circumstances of the nature, but in the investigation from the documentational records, it is originated in the treatment method of the Sam-Huang-O-Jae (三皇五帝 )period to cure the abnormal circulation of the vital force and blood caused by damp (濕). 2. As the principle and the method of the Life-Cultivation of the Chun-chu-Jeon-Kook (春秋戰國) periods were recorded in Huang-Jae-Nai-Gyung (黃帝內徑) detailly and the remedy examples by ancient Chi-Kung such as Tao-Yin (導引), Haeng-Chi (行氣) were presented, we considered that theoretical basis of the development of Life-cultivation and Chi-Kung study was furnished in that period. 3. A famous doctor, Hwa-Ta (華陀) lived in Han dynasty, researched the theory and practice of Tao-Yin transmitted from the former generations, as that result, he formed a kind of medical gymnastics what is called O-Keum-Hi (五禽戱). It is considered that 'O-Keum-Hi' is a Tao-Yin method developed more practically and systemetically than the Tao-Yin appeared in the 'Jang-Ja' (莊子) or 'Hoy-Nam-Ja' (淮南子). 4. In Wui-Jin-Nambook Jo (魏晋南北朝) periods, the contents of Chi-Kung were more abundant under the influence of Buddhism (佛敎) and Taoism (道敎). Galhong (葛洪), the author of 'Po-Bak-Ja' (抱朴子) arranged the ancient Chi-Kung method systematically first of all, Tao-Goeng-Gyung (陶宏景), the author of 'Yang-Seong-Yeun-Myung-Rok' (養性延命錄) recorded the 'Yook-Ja-Geul' (六字訣) first time. 5. There is a new development of Chi-Kung therapy in Soo-Tang-Odae (隋唐五代) pefiods, especially So-Won-Bang (巢元方), the author of 'Jey-Byung-Won-Hwu-Ron' (諸病源候論) collected aimost all of the Chi-Kung method, for curing the disease formed before soo (隋) period. From that fact, we supposed that Chi-Kung was utilized more widely in curing the disease. 6. 'So-Ju-Cheon-Hwa-Hu-Peob' (小周天火候法) was adopted as the best orthodox approach under the influence of Nae-Tan-Taoist (道敎內丹學派) in Song-Keum-Won (宋金元) periods, especially in the song dynasty, 'Pal-Dan-Geum' (八段錦) was appeared and assignment of six-Chi (六氣) for bowel and viscera in the 'Yook-Ja-Geul' (六字訣) was decided firmly, that is to say Lung-Si (肺-呬), Heart-Kha (心-呵), Spleen-Hoa (脾-呼), Liver-Hoe (肝-噓), Kidneychui (賢-吹), Three-Burner-shi (三焦-嘻). 7. In Myung-Cheong (明淸) periods, The general practitioner applied the principle of 'Byun-Jeng-Ron-Chi' (辨證論治) to the Chi-Kung field, and after Myeong dynasty the style of doing 'Yook-Ja-Gyel' (六字訣) was developed to the moving style. 8. Today, in china, the study on the Chi-Kung is being progressed constantly under the positive assistance of government, Chi-Kung-Hak (氣功學) has taking its place as a branch of study step by step. It is considered that the establishment of Chi-Kung-Hak Classroom (氣功學教室) and Medical Chi-Kung Center (氣功療法室) for special and systematic research are needed, at the same time the settlement of institutional system for training the Chi-Kung technician (氣功師) is also needed.

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The effects of foundation size on the seismic performance of buildings considering the soil-foundation-structure interaction

  • Nguyen, Quoc Van;Fatahi, Behzad;Hokmabadi, Aslan S.
    • Structural Engineering and Mechanics
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    • v.58 no.6
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    • pp.1045-1075
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    • 2016
  • Shallow footings are one of the most common types of foundations used to support mid-rise buildings in high risk seismic zones. Recent findings have revealed that the dynamic interaction between the soil, foundation, and the superstructure can influence the seismic response of the building during earthquakes. Accordingly, the properties of a foundation can alter the dynamic characteristics (natural frequency and damping) of the soil-foundation-structure system. In this paper the influence that shallow foundations have on the seismic response of a mid-rise moment resisting building is investigated. For this purpose, a fifteen storey moment resisting frame sitting on shallow footings with different sizes was simulated numerically using ABAQUS software. By adopting a direct calculation method, the numerical model can perform a fully nonlinear time history dynamic analysis to realistically simulate the dynamic behaviour of soil, foundation, and structure under seismic excitations. This three-dimensional numerical model accounts for the nonlinear behaviour of the soil medium and structural elements. Infinite boundary conditions were assigned to the numerical model to simulate free field boundaries, and appropriate contact elements capable of modelling sliding and separation between the foundation and soil elements are also considered. The influence of foundation size on the natural frequency of the system and structural response spectrum was also studied. The numerical results for cases of soil-foundation-structure systems with different sized foundations and fixed base conditions (excluding soil-foundation-structure interaction) in terms of lateral deformations, inter-storey drifts, rocking, and shear force distribution of the structure were then compared. Due to natural period lengthening, there was a significant reduction in the base shears when the size of the foundation was reduced. It was concluded that the size of a shallow foundation influences the dynamic characteristics and the seismic response of the building due to interaction between the soil, foundation, and structure, and therefore design engineer should carefully consider these parameters in order to ensure a safe and cost effective seismic design.