• Title/Summary/Keyword: Main Bearing

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Performance comparison of shear walls with openings designed using elastic stress and genetic evolutionary structural optimization methods

  • Zhang, Hu Z.;Liu, Xia;Yi, Wei J.;Deng, Yao H.
    • Structural Engineering and Mechanics
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    • v.65 no.3
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    • pp.303-314
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    • 2018
  • Shear walls are a typical member under a complex stress state and have complicated mechanical properties and failure modes. The separated-elements model Genetic Evolutionary Structural Optimization (GESO), which is a combination of an elastic-plastic stress method and an optimization method, has been introduced in the literature for designing such members. Although the separated-elements model GESO method is well recognized due to its stability, feasibility, and economy, its adequacy has not been experimentally verified. This paper seeks to validate the adequacy of the separated-elements model GESO method against experimental data and demonstrate its feasibility and advantages over the traditional elastic stress method. Two types of reinforced concrete shear wall specimens, which had the location of an opening in the middle bottom and the center region, respectively, were utilized for this study. For each type, two specimens were designed using the separated-elements model GESO method and elastic stress method, respectively. All specimens were subjected to a constant vertical load and an incremental lateral load until failure. Test results indicated that the ultimate bearing capacity, failure modes, and main crack types of the shear walls designed using the two methods were similar, but the ductility indexes including the stiffness degradation, deformability, reinforcement yielding, and crack development of the specimens designed using the separated-elements model GESO method were superior to those using the elastic stress method. Additionally, the shear walls designed using the separated-elements model GESO method, had a reinforcement layout which could closely resist the actual critical stress, and thus a reduced amount of steel bars were required for such shear walls.

Experimental study on the seismic performance of concrete filled steel tubular laced columns

  • Huang, Zhi;Jiang, Li-Zhong;Chen, Y. Frank;Luo, Yao;Zhou, Wang-Bao
    • Steel and Composite Structures
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    • v.26 no.6
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    • pp.719-731
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    • 2018
  • Concrete filled steel tubular (CFST) laced columns have been widely used in high rise buildings in China. Compared to solid-web columns, this type of columns has a larger cross-section with less weight. In this paper, four concrete filled steel tubular laced columns consisting of 4 main steel-concrete tubes were tested under cyclic loading. Hysteresis and failure mechanisms were studied based on the results from the lateral cyclic loading tests. The influence of each design parameter on restoring forces was investigated, including axial compression ratio, slenderness ratio, and the size of lacing tubes. The test results show that all specimens fail in compression-bending-shear and/or compression-bending mode. Overall, the hysteresis curves appear in a full bow shape, indicating that the laced columns have a good seismic performance. The bearing capacity of the columns decreases with the increasing slenderness ratio, while increases with an increasing axial compression ratio. For the columns with a smaller axial compression ratio (< 0.3), their ductility is increased. Furthermore, with the increasing slenderness ratio, the yield displacement increases, the bending failure characteristic is more obvious, and the hysteretic loops become stouter. The results obtained from the numerical analyses were compared with the experimental results. It was found that the numerical analysis results agree well with the experimental results.

A study of simulation in Cindy Sherman's image in body and violence (신디셔먼(Cindy Sherman)의 이미지에 나타난 시뮬라시옹 분석-신체와 폭력을 중심으로)

  • Lee, Ho-Young
    • Cartoon and Animation Studies
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    • s.20
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    • pp.121-139
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    • 2010
  • As a society gets digitalized, world of simulation will expand. The world of simulation is a forced, human-making world where we are going on our lives. It is power that dominates human beings. It is a main discourse producing forces. We are using violence to ourselves to escape this forcing phenomenon. Cindy Sherman is being paid attention as an artist who expresses physical human being in the world of simulation - human who desires something, is sacrificed by violence and is using violence to himself. She is casting a question about the violence of power in the world - who are you right now in the border between the real world and the fake one? - Her method is by various symbols: masks and makeup in her works, human desires and violent realities in symbolic packages. Only when we see the world as flesh, that is a specific body, not as separated organs, can this world be something we can feel. This world is something simulacre and at the same time is bearing violence in it. She sacrifices herself to violence to avoid the very violence. This behavior is to refine or avoid gigantic violence. She is saying that the others' pains, birth and death of flowers are not only theirs but also ours.

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Presumption on the Failures, the Causes and the Reliability of the Mist and Dust Blower (미스트기 부품의 고장실태조사에 의한 신뢰성의 예측)

  • 금동혁;최재갑
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.1
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    • pp.3702-3711
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    • 1975
  • This study was originated to investigate the imparired parts of the mist and dust blowers and intended to analyze the causes of their failures by the use of the Weibull probability paper. By the use of the paper, the parts which were needed to change the design, the force of the urgency, the mean time between failures of the parts and the basic causes of the troubles could be predicted. The survey showed that the following parts got out of order: (A) flexible rubber hose, (B) blowing fan, (C) lead valve, (D) piston ring. (E) crank main bearing, (F) coil in magneto and (G) needle valve in carburettor. The analysis of the survey indicated that the parts G, C, E and D were belonged to "wear-out failure", and that the mean time between failures became shorter in order as indicated above. To insure longer lives of those parts, it would be necessary to change the design and the material and to upgrade operators mechanical technique of the mist and dust blower. The failure of the parts A, B and F was classified as "randomfailure", and they did not seem to be the "wear-out" at that time. The parts B and F was evaluated as "initial failure". Quality controls and operating tests by the producer. and the operational training for users should be strengthened so as to eliminate these failures. Were the failures only in the parts A, C, D, E, F and G, it could be said that the "reliability" of the mist and dust blower would fall to 10 percent in the second year, and 50 percent of the mist and dust blowers would fail in all parts A, C, D, E, F and G before the blower would have control insect and disease in 58.2 hectares. The use of the Weibull probability paper for analyzing failures of the mist and dust blowers was effective in that it analyzed failure in the relationship between strength of the parts and users actual circumstanoes.

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Test Rig Development for Identification of Rotordynamic Force Coefficients of Squeeze Film Dampers in Automotive Turbocharger Bearing Systems (자동차 터보차저 베어링 시스템에 적용되는 스퀴즈 필름 댐퍼의 동적계수 측정을 위한 실험장치 개발)

  • Hwang, Jisu;Ryu, Keun;Jeung, Sung-Hwa
    • Tribology and Lubricants
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    • v.34 no.1
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    • pp.33-41
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    • 2018
  • This paper describes a new test rig for identification of rotordynamic force coefficients of squeeze film dampers (SFDs) in automotive turbochargers (TCs). Prior studies have mainly concentrated on relatively large-sized SFDs used in aircraft engines, turbocompressors, and turbopumps. The main objective of the current study is to propose a test rig for identification of dynamic force coefficients of small-sized SFDs (a journal diameter of ~11 mm). The current test rig consists of a journal, a SFD cartridge, four support rods, an upper structure, a data acquisition (DAQ) system, and an oil circulation unit. The annular gaps between the journal outer surface and SFD cartridge inner surface create SFD film lands. The damper has two parallel film lands separated by a central groove, having an axial length and depth of 3 mm. Each film land has a length of 4 mm with a $40{\mu}m$ radial clearance. The static load and dynamic impact tests identify the structural characteristics (i.e., stiffness and natural frequency) of the journal and assembled test rig. The measurements show good agreement with predictions. The SFD performance data from this test rig will be used to develop innovative TC rotor systems with improved NVH and reliability characteristics incorporating advanced SFD technology.

Phenotypic Diversity of Shea(Vitellaria Paradoxa C. F. Gaertn.) Populations across Four Agro-Ecological Zones of Cameroon

  • Nafan, Diarrassouba;Divine, Bup Nde;Cesar, Kapseu;Christophe, Kouame;Abdourahamane, Sangare
    • Journal of Crop Science and Biotechnology
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    • v.10 no.4
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    • pp.223-230
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    • 2007
  • Vitellaria paradoxa commonly called shea is an important agro forestry and fruit-bearing species present in four agro-ecological zones of Cameroon. The goal of this work was the morphological characterization of certain populations of V. paradoxa which will serve as a necessary step for a subsequent genetic study of the species. Morphological observations related to 20 agronomic traits, studied on 8-13 trees selected from each of the eight shea populations across four different agro-ecological zones located in four provinces of Cameroon were studied. The study showed that there was a variation between the populations, related to the traits measured on the trunk, fruit, nut, and leaf. Three shapes of the tree(ball, broom, and trained), five shapes of the fruit(round, oblong, reversed pear, ovoid, and oblong), three colors of the nut(clear brown, dark brown, and blackish brown) were identified. The principal component analysis(PCA) carried out on the quantitative characters revealed 72% of the total variance expressed on the first and second main axis. This variation was essentially explained by the traits measured on the fruits and on the nuts. The analyses showed that only the traits of the fruits and the nuts were discriminative. The shea populations studied were structured into two distinct groups using these discriminative traits.

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Genotype $\times$ Environment Interaction for Yield in Sesame (Sesamum indicum L.)

  • Shim, Kang-Bo;Kang, Churl-Whan;Hwang, Chung-Dong;Pae, Suk-Bok;Choi, Kyung-Jin;Byun, Jae-Cheon;Park, Keum-Yong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.53 no.3
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    • pp.297-302
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    • 2008
  • Application of genotype by environment ($G\;{\times}\;E$) interaction would be used for identifying optimum test condition of the varietal adaptation in the establishment of breeding purpose. Yield and yield components were used to perform additive main effect and multiplicative interaction (AMMI) analysis. Significant difference for $G\;{\times}\;E$ interaction were observed for all variable examined. For yield, 0.18 of total sum of squares corresponded to $G\;{\times}\;E$ interaction. Correlation analysis was carried out between genotypic scores of the first interaction principal component axis (IPCA 1) for agronomic characters. Significant correlations were observed between IPCA 1 for yield and capsule bearing stem length (CBSL), number of capsule per plant (NOC). The biplot of grain yield means for IPCA1 which accounted for 34% of the variation in total treatment sums of squares showed different reaction according to $G\;{\times}\;E$ interaction, genotypes and environments. Taegu showed relatively lower positive IPCA1 scores, and it also showed smaller coefficient variation of yield mean where it is recommendable as a optimal site for the sesame cultivar adaptation and evaluation trial. In case of variables, Yangbaek and M1 showed relatively lower IPCA1 scores, but the score direction showed opposite each other on the graph. Ansan, Miryang1, Miryang4, and Miryang6 seemed to be similar group in view of yield response against IPCA1 scores. These results will be helpful to select experimental site for sesame in Korea to minimize $G\;{\times}\;E$ interaction for the selection of promising genotype with higher stability.

Ore Minerals and the Physicochemical Environments of the Inseong Gold-Silver Deposits, Republic of Korea (인성(仁成) 금(金)·은(銀) 광상(鑛床)에서 산출(産出)되는 광석광물(鑛石鑛物)과, 물리화학적(物理化學的) 생성환경(生成環境))

  • Lee, Hyun Koo;Moon, Hi-soo
    • Economic and Environmental Geology
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    • v.22 no.3
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    • pp.237-252
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    • 1989
  • The Inseong gold-silver mine is located 3Km northwest of Suanbo, Choongcheongbugdo, Republic of Korea. The mine occurs in the shear zone formed by tension fractures within the Hwanggangri Formation of the Ogcheon metamorphic belt. Ore minerals found in the gold-silver bearing hydrothermal quartz vein composed mainly of pyrite, arsenopyrite, sphalerite, galena and minor amount of chalcopyrite, pyrrhotite, stannite, bismuthininte, native bismuth, chalcocite, electrum and tellurian canfieldite(?). The gangue minerals are quartz, calcite, chlorite and rhodochrocite. Wallrock alterations such as chloritization, silicitication, pyritization, carbonitization and sericitization can be observed in or around the quartz vein. According to the paragenetic sequence, quartz vein structure and mineral assemnlages, three different stages of ore formation can be recognized. The physico-chemical environment of ore formation in this deposit shows slight variation from stage to stage, but the condition of main ore deposition can be summarized as follows. Fluid inclusion, S-istope geothermometry and geothermometry based on mineral chemistry by use of arsenopyrite and chlorite show the ore was formed at temperature between 399 and $210^{\circ}C$ from fluids with salinities of 3.3-5.8 wt.% equivalent NaCl. It indicates that pressure during the mineralization is less than 0.6 Kb corresponding to a depth not greater than 1Km. S-isotope data suggests that thermal fluid may have magmatic origin wit some degree of mixing with meteoric water. In coclusion, the Inseong gold-silver deposit was formed at shallow depth and relatively high-temperature possibly with steep geothermal gradient under xenothermal condition.

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A Study on the Genesis of Eonyang Amethyst Deposits (언양(彦陽) 자수정 광상(鑛床)의 성인(成因)에 관한 연구(硏究))

  • Youn, Seok-Tai;Park, Hee-In
    • Economic and Environmental Geology
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    • v.27 no.4
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    • pp.335-343
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    • 1994
  • The Eonyang amethyst deposits are composed of vug quartz emplaced in the Eonyang granites of Mesozoic Cretaceous age. The Eonyang granites are composed of biotite granite, porphyritic biotite granite, aplite and miarolitic granite. The petrochemical data of the Eonyang granites show the trend of subalkaline magma, calc-alkaline magma, I-type granitoid and magnetite series. The vug quartz show the characteristic growth zoning (white quartz-smoky quartz-amethyst) from wall side. Generally fluid inclusions in the vug quartz can be divided into four main types based on compositions (I-type: gas inclusion, II-type: liquid inclusion, III-type: polyphase inclusion, IV-type: liquid $CO_2$-bearing inclusion). Solid phase of polyphase inclusions are halite(NaCl), sylvite(KCl), hematite ($Fe_2O_3$) and unknown anisotropic solid. Homogenization temperatures inferred from the fluid inclusion study ranges from $440^{\circ}C$ to $485^{\circ}C$ in white quartz, from $227^{\circ}C$ to $384^{\circ}C$ in smoky quartz, from $133^{\circ}C$ to $186^{\circ}C$ in amethyst, respectively. Salinities of fluid inclusions in each mineralization stages ranges from 40 wt.% to 58 wt.% in white and smoky quartz, from 1.0 wt.% to 8.7 wt.% in amethyst respectively. A consideration of the pressure regime during vug quartz deposition based on the boiling evidence suggests lithostatic pressure of less than 72 bars. This range of pressure indicate that vug quartz lay at depth of 750 m below the surface at the during mineralization.

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Evaluating the impacts of using piles and geosynthetics in reducing the settlement of fine-grained soils under static load

  • Shariati, Mahdi;Azar, Sadaf Mahmoudi;Arjomand, Mohammad-Ali;Tehrani, Hesam Salmani;Daei, Mojtaba;Safa, Maryam
    • Geomechanics and Engineering
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    • v.20 no.2
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    • pp.87-101
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    • 2020
  • The construction of combined pile-raft foundations is considered as the main option in designing foundations in high-rise buildings, especially in soils close to the ground surface which do not have sufficient bearing capacity to withstand building loads. This paper deals with the geotechnical report of the Northern Fereshteh area of Tabriz, Iran, and compares the characteristics of the single pile foundation with the two foundations of pile group and geogrid. Besides, we investigate the effects of five principal parameters including pile diameter and length, the number of geogrid layers, the depth of groundwater level, and pore water pressure on vertical consolidation settlement and pore water pressure changes over a year. This study assessed the mechanism of the failure of the soil under the foundation using numerical analysis as well. Numerical analysis was performed using the two-dimensional finite element PLAXIS software. The results of fifty-four models indicate that the diameter of the pile tip, either as a pile group or as a single pile, did not have a significant effect on the reduction of the consolidation settlement in the soil in the Northern Fereshteh Street region. The optimum length for the pile in the Northern Fereshteh area is 12 meters, which is economically feasible. In addition, the construction of four-layered ten-meter-long geogrids at intervals of 1 meter beneath the deep foundation had a significant preventive impact on the consolidation settlement in clayey soils.