• Structural Engineering and Mechanics
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• 제70권2호
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• pp.221-231
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• 2019

This paper performs for the first time a simultaneous optimization for members sections along with semi-rigid beam-to-column connections for space steel frames with fixed, semi-rigid, and hinged bases using a biogeography-based optimization algorithm (BBO) and a genetic algorithm (GA). Furthermore, a member's sections optimization for a fully fixed space frame is carried out. A real and accurate simulation of semi-rigid connection behavior is considered in this study, where the semi-rigid base connections are simulated using Kanvinde and Grilli (2012) nonlinear model, which considers deformations in different base connection components under the applied loads, while beam-to-column connections are modeled using the familiar Frye and Morris (1975) nonlinear polynomial model. Moreover, the $P-{\Delta}$ effect and geometric nonlinearity are considered. AISC-LRFD (2016) specification constraints of the stress and displacement are considered as well as section size fitting constraints. The optimization is applied to two benchmark space frame examples to inspect the effect of semi-rigidity on frame weight and drift using BBO and GA algorithms.

• Steel and Composite Structures
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• 제14권1호
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• pp.1-20
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• 2013

This paper presents the formulation for a novel force-based 1-D compound-element that captures both material and second order P-${\Delta}$ nonlinearities in steel frames. At the nodal points, the element is attached to nonlinear rotational and a translational springs which represent the flexural and axial stiffness of the connections respectively. By decomposing the total strain in the material as well as the generalised displacements of the flexible connections to their elastic and inelastic components, a secant solution strategy based on a direct iterative scheme is introduced and the corresponding solution strategy is outlined. The strain and slope of the deformed element are assumed to be small; however the equilibrium equations are satisfied for the deformed element taking account of P-${\Delta}$ effects. The formulation accuracy and efficiency is verified by some numerical examples on the nonlinear static, cyclic and dynamic analysis of steel frames.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.12-19
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• 2005

The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition and the connection type because it is organized by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling behavior of the structures is analyzed But, it is very difficult to design the single layer latticed domes considered all conditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base on the linear buckling load by the eigen-value analysis.

• 한국통신학회논문지
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• 제29권5C호
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• pp.595-600
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• 2004

선형복잡도(linear complexity)가 크고 균형(balance) 특성이 좋은 수열은 스트림 암호(stream cipher) 또는 보안성이 요구되는 대역 확산 통신(spread spectrum communication) 등에 이용될 수 있다. 이러한 수열을 발생하기 위하여, 최대길이 수열(m-sequence)을 계층 구조의 비선형 피드포워드 로직(NLFFL; Non-Linear Feed-Forward Logic) 필터 함수에 통과 시켜 랜덤 수열을 얻는 방법이 Groth에 의해 제안되었다. 본 논문에서는 Groth의 계층 구조를 변형하여 Langford 연결법과 같은 특별한 비선형 연결 방법 없이도 잡음 특성이 좋은 수열을 발생시킬 수 있는 방법을 제시한다.

• Journal of applied mathematics & informatics
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• 제4권1호
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• pp.83-108
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• 1997

Chebysheff-Halley methods are probably the best known cubically convergent iterative procedures for solving nonlinear equa-tions. These methods however require an evaluation of the second Frechet-derivative at each step which means a number of function eval-uations proportional to the cube of the dimension of the space. To re-duce the computational cost we replace the second Frechet derivative with a fixed bounded bilinear operator. Using the majorant method and Newton-Kantorovich type hypotheses we provide sufficient condi-tions for the convergence of our method to a locally unique solution of a nonlinear equation in Banach space. Our method is shown to be faster than Newton's method under the same computational cost. Finally we apply our results to solve nonlinear integral equations appearing in radiative transfer in connection with the problem of determination of the angular distribution of the radiant-flux emerging from a plane radiation field.

• 한국구조물진단유지관리공학회 논문집
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• 제7권2호
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• pp.209-218
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• 2003

The analytical studies included nonlinear finite element analysis of split-tee connection details subjected to axial load and lateral load. A three-dimensional model of the connections between CFT columns and H-beams has been developed. Both initial geometrical imperfections and residual stresses are taken into consideration. A geometrically nonlinear load-displacement analysis of the structure containing the imperfection is then performed, using the Riks method. Analytical results are compared with existing experimental results. Extensive parametric analyses are carried out to investigate the relation of the connections between CFT columns and H-beam to various parameters such as the axial load, column width-thickness ratio, and split-tee thickness.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
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• pp.147-153
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• 2005

The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition, and the connection type because it is originazed by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling of the structures is analyzed. But, it is very difficult to design the single layer latticed domes considered all conditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base of the linear buckling load by the eigenvalue analysis.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1996년도 The Korean Institute of Navigation 1996년도 한·중 국제학술 심포지움 및 추계학술발표회 논문집
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• pp.95-110
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• 1996

High Tensile Steel enables to reduce the plate thickness comparing to the case when Mild Steel is used. From the economical view point this is very preferable since the reduction in the hull weight. However to use the High Tensile Steel effectively the plate thickness may become thin so that the occurrence of buckling is inevitable and design allowing plate buckling may be necessary. If the inplane stiffness of the plating decreases due to buckling, buckling may be necessary. If the inplane stiffness of the plating decreases due to buckling the flexural rigidity of the cross section of a ship's hull also decreases. this may lead to excessive deflection of the hull girder under longitudinal bending. In these cases a precise estimation of plate's behavior after buckling is necessary and nonlinear analysis of isolated and stiffened plates is required for structural system analysis. In this connection this paper discusses nonlinear behaviour of thin plate under thrust. Based on the analytical method elastic large deflection analysis of isolated plate is perform and simple expression are derived to evaluate the inplane rigidity of plates subjected to uniaxial compression.

• 산업경영시스템학회지
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• 제12권19호
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• pp.31-37
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• 1989

본 논문은 비선형 회귀분석 모델(Nonlinear Regression Models)에서의 추산잔차(Recursive Residuals)를 정의하기 위한 것을 목적으로 한다. 선형 회귀분석 모델(Linear Regression Models)에서는 추산잔차가 우리가 측정할 수 없는 진짜 오차(True Error)와 같은 확률 분포를 갖는데 이의 평균은 0이고 분산은 ${sigma}^2$이다. 그러나 비선형 회귀분석에서는 이와 같은 정확한 분포를 알 수가 없기 때문에, 여러 종류의 잔차들을 연구 검토하고 나아가서 시뮬레이션(Simulation)을 통하여 분석.비교한 뒤 추산잔차를 정의하기로 한다.

• 한국전산구조공학회논문집
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• 제26권4호
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• pp.309-318
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• 2013

본 논문에서는 일체식 교대 교량의 장대화 및 내진성능 향상을 위해 가장 중요한 역할을 하는 교대-H형 강말뚝 연결부의 성능을 향상시키기 위하여 기존의 연결부의 균열형상을 파악하고, 이를 기반으로 새로운 형태의 연결부를 제안하기 위하여 철근을 활용하여 강성을 증가시키는 방법과 강말뚝의 형상을 개선하여 연성을 개선시키는 방법을 모색하였다. 먼저, 기존 연결부의 성능을 향상시키기 위하여 연결부 주변에 PennDOT에 규정된 철근상세와 나선철근의 배치와 HSS 튜브를 사용하였으나, PennDOT의 철근 상세와 HSS 튜브는 연결부의 성능을 향상시키지 못 했으나, 나선철근은 균열을 효과적으로 차단시키는 것을 확인할 수 있었다. 하지만, 철근의 구속효과로 인해 강말뚝의 저항력이 변위에 선형적으로 비례하여 증가하므로 교량의 상부구조에 축력을 발생시키는 효과를 가져왔다. 따라서, 강말뚝의 형상을 개선하기 위하여 콘크리트 교대에 매입된 부분의 플랜지를 제거하는 방법과 콘크리트 외부에서 플랜지의 폭을 축소시키는 형태를 검토하였다. 두 가지 방안 모두 균열을 억제하는데 효과적인 방법이었으나, 플랜지를 제거하는 쪽의 연결부가 더욱 효과적이었다.