• 한국생산제조학회지
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• 제23권3호
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• pp.291-298
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• 2014

This study uses two numerical approaches to analyze the filling behavior of micro patterns on micro-injection molding for V-grooves pattern which cannot be simulated with conventional CAE packages. The parametric studies have been performed to examine the fidelity of micro patterns with respect to temperature, pressure, inlet velocity and pattern location on the mold according to the boundary condition from the macro pressure and velocity data which can be obtained by conventional CAE packages. Through these numerical approaches, the filling behavior of polymer melt in micro patterns can be understood, the quality of replication can be predicted, and the V-groove pattern can be shaped uniformly during the process of injection molding.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.249-257
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• 1996

Dynamic Analysis of Precast Concrete Large Panel Structures with Horizontal Joints The damage in precast large panel structures subjected to destructive earthquakes is generally localized in the joints. Particularly, the horizontal joints influence on the stability and integrity of the overall structure. In this research a dynamic analysis was carried out by the macro model that idealized the horizontal joints as inelastic-nonlinear spring systems. It is capable of simulating the behavior of precast concrete structures using the mathematical model. As a result of the dynamic parametric study for the case of 0.12g peak base accelerations, it is found that all joints behave elastically for sliding and opening and that all forces are well distributed without excessive local concentration on my horizontal joints.

• Structural Engineering and Mechanics
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• 제55권3호
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• pp.555-581
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• 2015

Triangular pyramid and Quadrangular pyramid elements for partial double-layer spherical reticulated shells of pyramidal system are investigated in the present study. Macro programs for six typical partial double-layer spherical reticulated shells of pyramidal system are compiled by using the ANSYS Parametric Design Language (APDL). Internal force analysis of six spherical reticulated shells is carried out. Distribution regularity of the stress and displacement are studied. A shape optimization program is proposed by adopting the sequence two-stage algorithm (RDQA) in FORTRAN environment based on the characteristics of partial double-layer spherical reticulated shells of pyramidal system and the ideas of discrete variable optimization design. Shape optimization is achieved by considering the objective function of the minimum total steel consumption, global and locality constraints. The shape optimization of six spherical reticulated shells is calculated with the span of 30m~120m and rise to span ratio of 1/7~1/3. The variations of the total steel consumption along with the span and rise to span ratio are discussed with contrast to the results of shape optimization. The optimal combination of main design parameters for six spherical reticulated shells is investigated, i.e., the number of the optimal grids. The results show that: (1) The Kiewitt and Geodesic partial double-layer spherical reticulated shells of triangular pyramidal system should be preferentially adopted in large and medium-span structures. The range of rise to span ratio is from 1/6 to 1/5. (2) The Ribbed and Schwedler partial double-layer spherical reticulated shells of quadrangular pyramidal system should be preferentially adopted in small-span structures. The rise to span ratio should be 1/4. (3) Grids of the six spherical reticulated shells can be optimized after shape optimization and the total steel consumption is optimized to be the least.

• Computers and Concrete
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• 제33권4호
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• pp.385-398
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• 2024

As concrete dominates the construction industry, alternatives to traditionally used steel reinforcement are being sought. This study explored the suitability of carbon fiber-reinforced polymer (CFRP) as a substitute within rigid frames, focusing on its impact on section ductility and overall structural durability against seismic events. However, current design guidelines address quasi-static loads, leaving a gap for dynamic or extreme circumstances. Our approach included multiscale simulations, parametric study, and energy dissipation analyses, drawing upon a unique adaptation of modified compression field theory. In our efforts to optimize macro and microparameters to improve yield strength, manage brittleness, and govern failure modes, we also recognized the potential of CFRP's high corrosion resistance. This characteristic of CFRP could significantly reduce the frequency of required repairs, thereby contributing to enhanced durability of the structures. The research reveals that CFRP's durability and seismic resistance are attributed to plastic joints within compressed fibers. Notably, CFRP can impart ductility to structural designs, effectively balancing its inherent brittleness, particularly when integrated with quasi-brittle materials. This research challenges the notion that designing bendable components with carbon fiber reinforcement is impractical. It shows that creating ductile bending components with CFRP in concrete is feasible despite the material's brittleness. This funding overturns conventional assumptions and opens new avenues for using CFRP in structural applications where ductility and resilience are crucial.

• 한국지진공학회논문집
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• 제15권4호
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• pp.45-54
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• 2011

경계요소를 가지는 철근콘크리트 전단벽의 비선형 해석을 위한 간편 모델을 제안하였다. 이 간편 모델은 전단벽의 휨 및 전단 거동을 스프링요소로 나타낸 거시적 모델이다. 휨거동은 벽체의 단면해석을 기초로 한 모멘트강도와 회전능력을 벽체 양단의 수직 스프링요소로 나타내었다. 경계요소를 가지는 전단벽은 휨거동에 의해 지배되므로 전단거동은 휨거동에 바탕하여 변수를 계산하였고 중앙부 수평 스프링요소로 나타내었다. 제안된 모델은 전단벽 정적이력시험 결과와 비교한 후 비선형동적해석을 수행하여 사용된 이력법칙 및 변수들의 타당성을 조사하였다. 비선형동적해석을 이용한 변수연구를 통하여 내진성능평가의 주요변수인 요구값과 성능값에 미치는 영향을 검토하였다. 그 결과 전단력-전단변형 관계에서 약간의 차이가 있지만 전단벽의 전체거동은 잘 일치하였으며, 주요 변수의 변화에 대해 요구값과 성능값도 일정하게 변화하므로 제안된 해석모델은 경계요소를 가진 철근콘크리트 전단벽에 알맞은 것으로 판단된다.

• International Journal of Concrete Structures and Materials
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• 제10권4호
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• pp.479-497
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• 2016

Many experimental studies have evaluated the in-plane behavior of reinforced concrete frames in order to understand mechanisms that resist progressive collapse. The effects of transverse beams, frames and slabs often are neglected due to their probable complexities. In the present study, an experimental and numerical assessment is performed to investigate the effects of transverse beams on the collapse behavior of reinforced concrete frames. Tests were undertaken on a 3/10-scale reinforced concrete sub-assemblage, consisting of a double-span beam and two end columns within the frame plane connected to a transverse frame at the middle joint. The specimen was placed under a monotonic vertical load to simulate the progressive collapse of the frame. Alternative load paths, mechanism of formation and development of cracks and major resistance mechanisms were compared with a two-dimensional scaled specimen without a transverse beam. The results demonstrate a general enhancement in resistance mechanisms with a considerable emphasis on the flexural capacity of the transverse beam. Additionally, the role of the transverse beam in restraining the rotation of the middle joint was evident, which in turn leads to more ductile behavior. A macro-model was also developed to further investigate progressive collapse in three dimensions. Along with the validated numerical model, a parametric study was undertaken to investigate the effects of the removed column location and beam section details on the progressive collapse behavior.