• 한국지반공학회지:지반
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• 제11권4호
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• pp.5-12
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• 1995

말뚝의 재하시험이 연직지지력을 추정하기 위한 다양한 정보를 제공한다 할지라도 시험 말뚝을 극한하중까지 도달하도록 충분히 재하시킨다는 것은 상당히 어려운 일이며, 이와 같이 파괴시까지 재하하지 못한 말뚝의 연직재하시험의 결과로부터 지지력을 추정하는데 있어서 많은 도해적 방법과 수학적 방법이 시도되었다. 파괴하중을 추정하기 위하여 Southwel 연 이론을 기초로 최대곡률을 이용한 해석적 방법이 필자 등에 의하여 발표된 바 있다. 여기서 파괴하중은 Crowther가 정의한 바와 같이 특정한 기준 을 초과하였을 때의 하중으로 정의하였다. 본 논문은 최대곡률 방법에 의한 허용하중을 결정하기 위하여 Davission의 방법 및 DIN 4014의 허용하중과 비교하여 최대곡률 방법의 안전율을 2.5로 제안하였다. 그 결과 파괴시까지 재하하지 못한 연직재하시험의 결과치로부터 말뚝의 연직지지력을 추정 하는데 있어서 최대곡률 방법에 의한 허용하중의 결정은 타당성이 있는 것으로 판단되었다.

• Computers and Concrete
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• 제9권4호
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• pp.257-273
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• 2012

Based on the heterogeneous characterization of concrete at mesoscopic level, Realistic Failure Process Analysis ($RFPA^{3D}$) code is used to simulate the failure process of concrete-filled tubular (CFT) stub columns. The results obtained from the numerical simulations are firstly verified against the existing experimental results. An extensive parametric study is conducted to investigate the effects of different concrete strength on the behaviour and load-bearing capacity of the CFT stub columns. The strength of concrete considered in this study ranges from 30 to 110 MPa. Both the load-bearing capacity and load-displacement curves of CFT columns are evaluated. In particular, the crack propagation during the deformation and failure processes of the columns is predicted and the associated mechanisms related to the increased load-bearing capacity of the columns are clarified. The numerical results indicate that there are two mechanisms controlling the failure of the CFT columns. For the CFT columns with the lower concrete strength, they damage when the steel tube yields at first. By contrast, for the columns with high concrete strength it is the damage of concrete that controls the overall loading capacity of the CFT columns. The simulation results also demonstrate that $RFPA^{3D}$ is not only a useful and effective tool to simulate the concrete-filled steel tubular columns, but also a valuable reference for the practice of engineering design.

• 전기학회논문지
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• 제56권6호
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• pp.1031-1034
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• 2007

Electric transmission lines pass through a variety of area. Foundation supporting the conductors and tower are selected properly in accordance with external load, for example dead load, wind load, snow load, construction load etc, and topography and geology condition. Typical types of foundation are as follows: pad foundation for small load and hard soil or rock in mountainous area, pile foundation for medium or large load and soft soil in plain field area. This paper introduced cylindrical foundation design & construction for large load and mountainous area. This foundation failure mode against pulling-out show splitting failure by tensile force toward circumferential direction.

• Structural Engineering and Mechanics
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• 제6권7호
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• pp.757-772
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• 1998

The objective of the present work is to estimate the strength and failure characteristics of symmetric thin square laminates under negative shear load. Two progressive failure analyses, one using the Hashin criterion and the other using a Tensor polynomial criterion, are used in conjunction with the finite element method. First-order shear-deformation theory along with geometric nonlinearity in the von Karman sense has been incorporated in the finite element modeling. Failure loads, associated maximum transverse displacements, locations and modes of failure including the onset of delamination are discussed in detail; these are found to be quite different from those for the positive sheer load reported in Part I of this study (Singh et al. 1998).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.357-362
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• 2001

The pipe fracture tests were performed on 102mm-Sch.80 carbon steel pipe with various local wall thinning shapes, in order to understand failure behavior of thinned pipe. Pipe specimens were subjected to monotonic bending moment, using 4-points loading system, under internally pressurized condition. From the results of experiment, the failure mode, load carrying capacity, and deformability of local wall thinning pipe were investigated. Failure mode of thinned pipe depended on magnitude of internal pressure and thinning length as well as loading direction and thinning depth and angle. The variation in load carrying capacity and deformability of thinned pipe with length of thinned area was determined by stress type appled to thinning region and circumferential thinning angle. Also, the effect of internal pressure on failure behavior was dependent on failure mode of thinned pipe, and it promoted crack occurrence and mitigated local buckling at thinned area.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.153-156
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• 2006

This paper presents an analytical results on limits of debonding failure for RC beams strengthened with near-surface mounted(NSM) CFRP strips. An analytical model was derived to predict the failure mode and the maximum load. An analytical model has two assumptions. The first is that the debonding failure occurs at the epoxy-concrete interfaces. The second is that the debonding failure occurs at the end of the FRP reinforcement due to concentration of shear stress. Results of the comparison of existing test data and analytical model data have predicted the failure mode and the maximum load well. Also, this paper proposed limits of debonding failure to prevent the debonding using the strengthening area and the groove depth.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.329-336
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• 2006

The resistance spot-welded region in most current finite element crash models is characterized as a rigid beam at the location of the welded spot. The region is modeled to fail with a failure criterion which is a function of the axial and shear load at the rigid beam. The calculation of the load acting on the rigid beam is important to evaluate the failure of the spot-weld. In this paper, numerical simulation is carried out to evaluate the calculation of the load at the rigid beam. At first, the load on the spot-welded region is calculated with the precise finite element model considering the residual stress due to the thermal history during the spot welding procedure. And then, the load is compared with the one obtained from the model used in the crash analysis with respect to the element size, the element shape and the number of imposed constraints. Analysis results demonstrate that the load acting on the spot-welded element is correctly calculated by the change of the element shape around the welded region and the location of welded constrains. The results provide a guideline for an accurate finite element modeling of the spot-welded region in the crash analysis of vehicles.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.94-97
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• 2005

The strength of aluminum 7075 and carbon composite hybrid joints was studied for adhesive, bolt, and the adhesive-bolt combined joints. Several hybrid joint specimens were tested to get the failure load and modes for three types of the joints. Adhesive Cytec EA9394S was used for aluminum and carbon bonding. Failure load of the adhesive-bolt combined joint was 94 % of the sum of the failure load of the separately bonded and bolted joints. Hybrid joint also showed more stable failure behavior than the simple adhesive or bolted joint.

• Structural Engineering and Mechanics
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• 제67권1호
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• pp.93-104
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• 2018

The seismic behavior of reinforced concrete (RC) short columns with limited transverse reinforcement is investigated in this paper through an experimental program. The experimental program consists of four small-scale RC columns with an aspect ratio of 1.7, which are tested to the axial failure stage. The cracking patterns, hysteretic responses, strains in reinforcing bars, displacement decomposition and cumulative energy dissipation of the tested specimens are reported in detail in the paper. The effects of column axial load are investigated to determine how this variable might influence the performance of the short columns with limited transverse reinforcement. Brittle shear failure was observed in all tested specimens. Beneficial and detrimental effects on the shear strength and drift ratio at axial failure of the test specimens due to the column axial load are found in the experimental program, respectively.

• 한국안전학회지
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• 제21권6호
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• pp.14-19
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• 2006

This study performed burst tests using real-scale pipe elbow containing simulated local wall-thinning to evaluate the effects of circumferential thinning angle and bending load on the failure pressure of wall-thinned elbow. The tests were carried out under the loading conditions of internal pressure and combined internal pressure and bending loads. Three circumferential thinning angles, ${\theta}/{\Pi}=0.125,\;0.25,\;0.5$, and different thinning locations, intrados and extrados, were considered. The test results showed that the failure pressure of wall-thinned elbow decreased with increasing circumferential thinning angle for both thinning locations. This tendency is different from that observed in the wall-thinned straight pipe. Also, the failure pressure of intrados wall-thinned elbow was higher than that of extrados wall-thinned elbow with the same thinning depth and equivalent thinning length. In addition, the effect of bending moment on the failure pressure was not obvious.