• Steel and Composite Structures
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• 제5권6호
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• pp.459-484
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• 2005

In recent years, the use of steel tube confined concrete (STCC) columns has been the interests of many structural engineers. The present study is an attempt to study the monotonic and cyclic behaviours of STCC columns. For the monotonic behaviours, a series of tests on STCC stub columns (twenty one), and beam-columns (twenty) were carried out. The main parameters varied in the tests are: (1) column section types, circular and square; (2) tube diameter (or width) to thickness ratio, from 40 to 162, and (3) load eccentricity ratio (e/r), from 0 to 0.5. For the cyclic behaviours, the test parameters included the sectional types and the axial load level (n). Twelve STCC column specimens, including 6 specimens with circular sections and 6 specimens with square sections were tested under constant axial load and cyclically increasing flexural loading. Comparisons are made with predicted column strengths and flexural stiffness using the existing codes. It was found that STCC columns exhibit very high levels of energy dissipation and ductility, particularly when subjected to high axial loads. Generally, the energy dissipation ability of the columns with circular sections was much higher than those of the specimens with square sections. Comparisons are made with predicted column strengths and flexural stiffness using the existing codes such as AIJ-1997, AISCLRFD- 1994, BS5400-1979 and EC4-1994.

• 한국유체기계학회 논문집
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• 제20권2호
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• pp.63-68
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• 2017

This paper predicts the rotordynamic force coefficients of tilting pad journal bearings (TPJBs) with ball-socket pivot and compares the predictions to the published test data obtained under load-between-pad (LBP) configuration. The present TPJB model considers the pivot stiffness calculated based on the Hertzian contact stress theory. Due to the compliance of the pivot, the predicted journal eccentricity agree well with the measured journal center trajectory for increasing static loads, while the early prediction without pivot model consideration underestimates it largely. The predicted pressure profile shows the significant pressure development even on the unloaded pads along the direction opposite to the loading direction. The predicted stiffness coefficients increase as the static load and the rotor speed increase. They agree excellently with test data from open literature. The predicted damping coefficients increase as the static load increases and the rotor speed decreases. The prediction underestimates the test data slightly. In general, the current predictive model including the pivot stiffness improves the accuracy of the rotordynamic performance predictions when compared to the previously published predictions.

• 한국산학기술학회논문지
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• 제11권3호
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• pp.1047-1052
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• 2010

이 연구에서는 진동타입기에 의해 시공되는 강널말뚝의 횡방향진동모델에 대해 횡방향스프링상수를 달리하여 횡방향진동에 따른 에너지손실 및 하중감소계수에 미치는 영향을 살펴보았다. 강널말뚝의 자유길이에 따른 에너지손실과 하중감소계수는 계산에서 고려한 횡방향스프링상수의 크기에 관계없이 강널말뚝의 휨강성보다는 편심거리의 크기에 영향을 크게 받는 것으로 나타났다. 그리고 계산에서 고려한 횡방향 스프링상수값, 10000N/m 이상일 경우 말뚝의 자유길이에 따른 하중감소계수가 수렴함을 알 수 있었다.

• 한국정밀공학회지
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• 제22권5호
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• pp.159-166
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• 2005

A self-compensated water-hydrostatic bearing is well known to have advantages in stiffness. In this paper, its concept is extended to a hydrostatic journal bearing for achieving higher stiffness. The finite element method is applied to analyze the load characteristics of the self-compensated hydrostatic journal bearing. The analysis results reveal that the self-compensated journal bearing has higher load capacity and higher stiffness than conventional, fixed capillary journal bearings. and that this benefit degrades in the case of high eccentricity. Thus, a spindle system with self-compensated journal bearings must be designed to ensure a sufficiently large load capacity. A rectangular type capillary is also introduced with consideration of the practical application of the self-compensated hydrostatic journal bearing. Theoretical analysis results show that the rectangular type capillary is more beneficial than conventional annular type capillaries in practical use. The experimental verification on the analysis method is made to show that the experimental results are in good agreement with theoretical results.

• 한국공간구조학회논문집
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• 제23권3호
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• pp.71-78
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• 2023

Recently, Free-Form and Irregular Shape high-rise buildings are constructed by IT technology development. Tilted shaped high-rise building which is one of Irregular shape high-rise buildings can cause lateral displacement by gravity load and lateral load due to tilted elevation shape. Therefore, it is necessary to review the behavior and structural aspects of the Tilted shape high-rise building by gravity load. In this paper, the dynamic characteristics of a tilted structure with a dual-core were analyzed with the core location as a design variable, and response behavior, vulnerable members, and vulnerable layers to earthquake loads were analyzed. As a result of the analysis, as the location of the core moved in an tilted direction, the eccentric distance and eccentric load decreased, reducing the axial force of the vertical members. However, the location of the core had little effect on the response.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 춘계 학술발표회 논문집
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• pp.266-274
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• 2002

A typical case where the effects of prying in the base angle type anchorage system with expansion bolt. This connection consists of an angle which is attathed to an equipment cabinet and bolted to a concrete slab via an expantion bolt. A seismic analysis of the cabinet may indicate a vertical load, P, transferred to the vertical leg of the angle due to overturning of the cabinet. Due to the eccentricity, b(e), and the continuous beam action in the base member, the load resisted by the bolt will be amplified by a factor λ. Thus, in this study, experimental evaluation of the anchorage system is executed.

• 대한기계학회논문집A
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• 제22권4호
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• pp.859-867
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• 1998

An oil lubricated Herringbone aroove jounal bearing(HGJB) with eight-circular-profile grooves on the non-rotating bearing surface is analyzed numerically and experimentally. The load carrying capacity, attitude angle, stiffness and damping coefficients are obtained numerically for the various bearing configurations. The onset speed of instability is also examined for the various eccentricity ratios. The configuration parameters of HGJB, such as groove depth ratio, groove width ratio, and groove angle, are dependent on each other because the grooves are generated by using eight small balls rolling over the inner surface of the sleeve with press fit. Therefore, it is not allowed to suggest a set of optimal design parameters such as the one for the rectangular profile HGJB. The overall results from numerical and experimental analysis prove that the circular profile HGJB has an excellent stability characteristics and the higher load carrying capacity than the plain journal bearing.

• 대한기계학회논문집
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• 제18권8호
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• pp.2026-2038
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• 1994

A numerical scheme is developed for the analysis of incipient sliding contact with orthotropic friction condition subjected to tangential load and twisting moment. The inherent nonlinearity in the orthotropic friction law has been treated by a polyhedral friction law. Then, a three-dimensional linear complementarity problem(LCP) formulation in an incremental form is obtained, and the existence of a solution is investigated. A Lemke's complementary pivoting algorithm is used for solving the LCP. The scheme is illustrated by spherical contact problems, and the effects of eccentricity of elliptical friction domain on the traction and stick region are discussed.

• Geomechanics and Engineering
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• 제7권6호
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• pp.679-703
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• 2014

This paper investigates nonlinear response of 51 laterally loaded rigid piles in sand. Measured response of each pile test was used to deduce input parameters of modulus of subgrade reaction and the gradient of the linear limiting force profile using elastic-plastic solutions. Normalised load - displacement and/or moment - rotation curves and in some cases bending moment and displacement distributions with depth are provided for all the pile tests, to show the effect of load eccentricity on the nonlinear pile response and pile capacity. The values of modulus of subgrade reaction and the gradient of the linear limiting force profile may be used in the design of laterally loaded rigid piles in sand.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.62-65
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• 2006

This study investigated the behavior of R/C column confined with headed crossties subjected to eccentric loading. The 16 specimens are designed to have adequate confinement steel, determined by ACI seismic design. The variables studied in this research test are eccentricity to depth ratios, spacing of lateral steel and the anchor type of end of crossties. From the test results, all columns showed similar behavior up to the peak load but those columns laterally confined with head presented more ductile behavior after the peak load. The comparisons indicate that the flexural behavior of confined-concrete columns can be computed resonable accurately by P-M interaction curve.