• Structural Engineering and Mechanics
• /
• 제41권2호
• /
• pp.157-181
• /
• 2012

The paper presents a review of the application of the newly proposed mixed finite element model for seismic simulation of different types of composite frame structures. To evaluate the performance of the element, a comparison with displacement-based and force-based models is conducted. The study revealed that the mixed model is superior to the others in terms of both speed of convergence and numerical stability, and is therefore considered the most practical approach for modeling of composite structures. In this model, the element is derived using independent force and displacement shape functions. The nonlinear response of the frame element is based on the section discretization into fibers with uniaxial material models. The interfacial behavior is modeled using an inelastic interface element. Numerical examples to clarify the advantages of the model are presented for the following structural applications: anchored reinforcing bar problems, composite steel-concrete girders with deformable shear connectors, beam on elastic foundation elements, R/C girders strengthened with FRP sheets, R/C beam-columns with bond-slip, and prestressed concrete girders. These studies confirmed that the model represents a major advancement over existing elements in simulating the inelastic behavior of composite structures.

• 한국수산과학회지
• /
• 제44권1호
• /
• pp.37-44
• /
• 2011

We investigated the optimum formulation to improve the gelling ability of squid, Dosidicus gigas, surimi. The solubility of minced squid muscle was highest at pH 10.7, and lowest at pH 5.0. The yields of conventional surimi and protein recovery after alkaline pH-shift processing were $68.1{\pm}2.4%$ and $65.3{\pm}2.6%$, respectively, whereas the protein recovery with acidic pH-shift processing was only $21.2{\pm}1.6%$. The addition of 5% starch decreased the breaking force regardless of the kind of starch, while the mixture of corn, potato, and wheat starch (total 15%) increased the breaking force by up to 1.9 fold. The addition of 5% egg white, 5% porcine plasma protein, 0.3% $CaCl_2$, and 0.3% Polymix GA significantly increased the breakingforce (P<0.05). None of the ingredients examined in this study significantly affected the deformation value (P<0.05). The optimum concentrations of egg white and $CaCl_2$ to obtain a breaking force of 55 g and a whiteness of 70 were 2.69% and 0.22%, respectively.

• 한국군사과학기술학회지
• /
• 제14권3호
• /
• pp.458-466
• /
• 2011

In war time, minimizing the logistics response time for supporting military operations is strongly needed. In this paper, i propose the mathematical formulation for minimizing the maximal acquisition completion time in wartime or during a state of emergency. The main structure of this formulation is based on the traveling purchaser problem (TPP), which is a generalized form of the well-known traveling salesman problem (TSP). In the case of the general TPP, an objective function is to minimize the sum of the traveling cost and the purchase cost. However, in this study, the objective function is to minimize the traveling cost only. That's why it's more important to minimize the traveling cost (time or distance) than the purchase cost in wartime or in a state of emergency. I generate a specific instance and find out the optimal solution of this instance by using ILOG OPL STUDIO (CPLEX version 11.1).

• Structural Engineering and Mechanics
• /
• 제36권5호
• /
• pp.625-642
• /
• 2010

The Integrated Force Method (IFM) is a novel matrix formulation developed for analyzing the civil, mechanical and aerospace engineering structures. In this method all independent/internal forces are treated as unknown variables which are calculated by simultaneously imposing equations of equilibrium and compatibility conditions. This paper presents a new 12-node serendipity quadrilateral plate bending element MQP12 for the analysis of thin and thick plate problems using IFM. The Mindlin-Reissner plate theory has been employed in the formulation which accounts the effect of shear deformation. The performance of this new element with respect to accuracy and convergence is studied by analyzing many standard benchmark plate bending problems. The results of the new element MQP12 are compared with those of displacement-based 12-node plate bending elements available in the literature. The results are also compared with exact solutions. The new element MQP12 is free from shear locking and performs excellent for both thin and moderately thick plate bending situations.

• Journal of applied mathematics & informatics
• /
• 제26권1_2호
• /
• pp.45-60
• /
• 2008

Here we consider the evaluation of the the dynamic component of the second order force due to wave diffraction by a circular cylinder analytically and numerically. The cylinder is fixed, vertical, surface piercing in water of finite uniform depth. The formulation of the wave-structure interaction is based on the assumption of a homogeneous, ideal, incompressible, and inviscid fluid. The nonlinearity in the wave-structure interaction problem arises from the free surface boundary conditions, namely, dynamic and kinematic free surface boundary conditions. We expand the velocity potential and free surface elevation functions in terms of a small parameter and then consider the second order diffraction problem. After deriving the pressure using Bernoulli's equation, we obtain the analytical expression for the dynamic component of the second order force on the cylinder by integrating the pressure over the wetted surface. The computation of the dynamic force component requires only the first order velocity potential. Numerical results for the dynamic force component are presented.

• Smart Structures and Systems
• /
• 제8권2호
• /
• pp.157-172
• /
• 2011

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

• 한국식품영양과학회지
• /
• 제33권10호
• /
• pp.1676-1684
• /
• 2004

어육, 닭 가슴살 및 돼지 후지 육을 산성 및 알칼리 용액으로 추출하여 등전점 부근에서 회수하고 중성 부근의 pH로 재조절하여 회수한 단백질의 가열 젤 물성과 이들의 혼합에 따른 가열 물성 값의 변화, 최적 물성과 최소비용을 제공하는 혼합 비율을 결정하였다. 갈고등어의 근원섬유단백질은 산 및 알칼리 처리에 의해 가열 젤을 형성하지 못하였으나, 산과 알칼리 처리후 근형질 단백질을 포함한 회수 단백질은 가열 젤을 형성하였다. pH 10.5에서 처리 후 회수한 단백질의 가열 젤의 파괴강도는 갈고등어가 가장 낮았고, 변형 값은 냉동 꼬마민어>닭 가슴살>돼지 후지 육>갈고등어의 순으로 높았으며, 백색도는 냉동 꼬마민어 회수 단백질이 가장 높았다. 갈고등어 회수 단백질의 첨가는 파괴강도, 변형 값, 백색도를 감소시키고 가격을 상승시키는 반면, 닭 가슴살 회수 단백질의 첨가는 파괴 강도와 백 색도를 다소 증가시키고 가격을 현저히 감소시켰다. 냉동 꼬마민어 회수 단백질인 경우, 파괴강도 110 g 이상, 변형 값 4.5 mm 이상 및 회수 단백질의 원료 단가 2000원 이하/kg을 만족하는 최적 혼합 비율은 냉동 꼬마민어 36∼50%, 닭 가슴살 34∼40%, 돼지 후지 육 14∼25%이었다 가열 젤의 구조는 냉동 꼬마민어 회수 단백질이 가장 치밀하였다. 냉동 꼬마민어 회수 단백질을 축으로 닭 가슴살, 돼지 후지 육 회수 단백질의 적절한 혼합 비율의 조절은 물성 값이 다양화한 연제품에 활용 가능할 것으로 판단된다.

• Nuclear Engineering and Technology
• /
• 제43권5호
• /
• pp.447-458
• /
• 2011

This paper proposes an approximated contact force model to identify the nonlinear behavior of a fuel rod with gap supports; also, the numerical prediction of interfacial forces in the mechanical contact of fuel rods with gap supports is studied. The Newmark integration method requires the current status of the contact force, but the contact force is not given a priori. Taylor's expansion can be used to predict the unknown contact force; therefore, it should be guaranteed that the first derivative of the contact force is continuous. This work proposes a continuous and differentiable contact force model with the ability to estimate the current state of the contact force. An approximated convex and differentiable potential function for the contact force is described, and a variational formulation is also provided. A numerical example that considers the particularly stiff supports has been studied, and a fuel rod with hardening supports was also examined for a realistic simulation. An approximated proper solution can be obtained using the results, and abrupt changes from the contacting state to non-contacting state, or vice versa, can be relieved. It can also be seen that not only the external force but also the developed contact force affects the response.

• 한국식품영양과학회지
• /
• 제32권7호
• /
• pp.1032-1038
• /
• 2003

전갱이 육으로 제조한 알칼리 수리미의 가열 겔 강도 증강을 위한 최적 전분 및 비근육 단백질의 선정과 이들 성분의 최적 첨가량을 설정하기 위해 2수준 fractional factorial과 mixture design을 실시하였으며, 반응 값은 punch test에 의한 물성과 색차계로 색을 측정하였다. 감자, 옥수수 및 밀전분은 파괴 강도 값을 감소시키지만 변형 값에는 유의적인 영향을 미치지 않는 것으로 나타났다. 소혈청 단백질은 파괴강도 값을 크게 증가시킨 반면 분말 난백 단백질은 다소 효과가 인정되었고 유장단백질과 대두 농축 단백질은 효과가 없었다. 그리고 소 혈청 단백질은 변형값을 다소 증가시킨 반면 분말 난백 단백질을 크게 감소시켰다. 감자와 옥수수 전분과 비근육 단백질은 백색도를 다소 개선하였다. 파괴강도 110g 이상, 변형 값 4.2 mm이상, 백색도 22.5 이상을 보이는 수리미, 옥수수전분 및 소혈청의 최적 혼합 비율은 각각 89.5∼90.0%, 4.6∼6.0%, 4.3∼5.4%의 범위였다. 전분과 비근육 단백질을 첨가하여 제조한 전갱이 알칼리 수리미의 가열 겔이 수세 수리미 겔에 비하여 균일한 단백질 분포를 보이고 있었다.

• Journal of Mechanical Science and Technology
• /
• 제16권10호
• /
• pp.1239-1245
• /
• 2002

A formulation which seeks steady-state equilibrium positions of constrained multibody systems driven by constant generalized speeds is presented in this paper. Since the relative coordinates are employed, constraint equations at cut joints are incorporated into the formulation. To obtain the steady-state equilibrium position of a multibody system, nonlinear equations are derived and solved iteratively. The nonlinear equations consist of the force equilibrium equations and the kinematic constraint equations. To verify the effectiveness of the proposed formulation, two numerical examples are solved and the results are compared with those of a commercial program.