• Journal of Mechanical Science and Technology
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• v.14 no.2
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• pp.197-206
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• 2000

A boundary integral equation method in the shape design sensitivity analysis is developed for the elasticity problems with axisymmetric non-homogeneous bodies. Functionals involving displacements and tractions at the zonal interface are considered. Sensitivity formula in terms of the interface shape variation is then derived by taking derivative of the boundary integral identity. Adjoint problem is defined such that displacement and traction discontinuity is imposed at the interface. Analytic example for a compound cylinder is taken to show the validity of the derived sensitivity formula. In the numerical implementation, solutions at the interface for the primal and adjoint system are used for the sensitivity. While the BEM is a natural tool for the solution, more generalization should be made since it should handle the jump conditions at the interface. Accuracy of the sensitivity is evaluated numerically by the same compound cylinder problem. The endosseous implant-bone interface problem is considered next as a practical application, in which the stress value is of great importance for successful osseointegration at the interface. As a preliminary step, a simple model with tapered cylinder is considered in this paper. Numerical accuracy is shown to be excellent which promises that the method can be used as an efficient and reliable tool in the optimization procedure for the implant design. Though only the axisymmetric problem is considered here, the method can be applied to general elasticity problems having interface.

• Structural Engineering and Mechanics
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• v.48 no.1
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• pp.41-56
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• 2013

Initiation and growth of delamination is a great concern of designers of composite structures. Interface elements with de-cohesive constitutive law in the content of continuum damage mechanics can be used to predict initiation and growth of delamination in single and mixed mode conditions. In this paper, an interface element based on the cohesive zone method has been developed to simulate delaminatoin growth of post-buckled laminate under fatigue loading. The model was programmed as the user element and user material by the "User Programmable Features" in ANSYS finite element software. The interface element is a three-dimensional 20 node brick with small thickness. Because of mixed-mode condition of stress field at the delamination-front of post-buckled laminates, a mixed-mode bilinear constitutive law has been used as user material in this model. The constitutive law of interface element has been verified by modelling of a single element. A composite laminate with initial delamination under quasi-static compressive Loading available from literature has been remodeled with the present approach. Moreover, it will be shown that, the closer the delamination to the free surface of laminate, the slower the delamination growth under compressive fatigue loading. The effects of laminate configuration on delamination growth are also investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.26-34
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• 2005

In this paper, a novel moving least squares interface welding method is proposed to carry out the coupled analysis of whole model composed of independently modeled finite element substructures with nodal mismatching interfaces. To verify the validity, and efficiency of the proposed interface welding method, various numerical examples are worked out including patch tests, convergence tests, and examples of coupled analyses of the structural systems with mismatching substructures. From the numerical tests, it is confirmed that one can efficiently carry out the coupled analysis of whole model composed of mismatching finite element substructures through the proposed method without any remeshing or any additional unknown.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.6
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• pp.1872-1881
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• 1996

LBB(Leak-Before-Break) analysis is performed for the highest stress location of each different type of mateerials in the nuclear piping line. In most cases, the highest stress occurs in the pipe and nozzle interface location. i.e. terminal end. The current finite element analysis approach utilizes the symmetry condition both for locations near the nozzle and for locationa away from the nozzle to minimize the size of the finite element model and to make analysis simple when calculating the J-integral values at the crack tip. In other words, the nozzle is not included in the finite element model. However, in reality, the symmetric condition is not applicable for the pipe-nozzle interface location. Because the pipe-nozzle interface location is asymmetric due to different stiffenss of the pipe and nozzle(both material and dimensions). The simplified analysis approach for pipe-nozzle interface locaiton is too conservative for a smaller diameter piping. In tlhis paper, various analyses are performed for the range of materials and crack sizes to evaluate the nozzle effect for a LBB anlaysis. This paper presents methodology for developing the piping evaluaiton diagram at the pipe-nozzle interface location.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.86-89
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• 2006

In this research, the decrease of the tensile strength in CFRP was investigated by experimental and analytical methods. We focused on the role of the interface between the reinforcing fiber and the epoxy resin matrix. The tensile and the interface strengths in CFRF were evaluated using the strand and the short beam specimens. Curtin's model which correlate the mechanical strength of the interface to the tensile strength was introduced for analytical study. The experimental and the analytical results showed good coincidence and we found that the interface strength is the key factor which governs the CFRP's tensile strength.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.545-548
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• 2000

A fundamental tenet of CBD is that a component has a specification which describes what that component does, and how it behaves when its services are used. In general, the implementation may be written in a different programming language and execute on different technology platform, from the language and platform used by the client program. In order to implement practically the system that is designed by the Farmer model, there is need to have the ISM (Interface Specification Model) which explains specification about the functions of entities of the Farmer model, such as, entity node, aspect node and ILB/OLB. This paper suggests the transformation methodology from the concepts of the Farmer model to the mapping notions of the ISM. Also in reality, TMN agents system which is designed by the Farmer model is transformed to the ISM system design.

• Computers and Concrete
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• v.7 no.2
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• pp.145-158
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• 2010

In this work the implementation of a production-level port of the Microplane constitutive model for concrete into the EPIC code is described. The port follows guidelines outlined in the Material Model Module (MMM) standard used in EPIC to insure a seamless interface with the existing code. Certain features of the model were not implemented using the MMM interface due to compatibility reasons; for example, a separate module was developed to initialize, store and update internal state variables. Objective strain and deformation measures for use in the material model were also implemented into the code. Example calculations were performed and illustrate the veracity of this new implementation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.375-382
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• 2011

There is no system to obtain the basic data and proceed data and user input interface is complex, thus there are some limitation to utilize the oil spill prediction model. It is difficult to build the scientific response strategy in order to respond oil spill accident rapidly because it is impossible to operate the oil spill prediction model any time. In this study, the optimum operational system for oil spil prediction model has been developed considering the present system. External real time data has been linked because of impossibility of building all basic data and minimum database has been build in this study. Through this data system, real time oil spill prediction model can be utilized. And the user interface has been designed to reduce the error of the interface between user and model and the output interface has been proposed to analyze the result of modeling at multidimensional aspect. While the system for oil spill prediction model as the result of this study has some uncertainties because of depending on external data, the thing that we can predict oil spill using operate the model rapidly as soon as the accident occurred can be meaning in the response field.

• Proceedings of the ESK Conference
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• 1998.04a
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• pp.93-98
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• 1998

Recently, consumers are tend to purchase the user-centered designed product using interface enginnering and human factors techniques. Therefore, it is important that the designer's requirements should be analyzed focused on the human machine interface. This paper described the interface usability evaluation technique(suvjective evaluation) for the interface between user and product. This methodology is the integrated interface usbility evaluation method AHP and Conjoint Analysis. AHP(Analytic Hierarchy Process) is a multicriteria decision model to give priority after expressing hierarchically for decision making problem. Conjoint Analysis enduavors to unravel the value, or partworths, that consumers place on the product or service's attributes from experimental subjects' evluation of profiles based on hypothetical products or services. A new usability test methodology proposed by this paper includes techniques jointed both consistency test by AHP and experimental subjective evaluation of profiles by Conjoint Analysis for evaluating the user's emotion and impression.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1785-1794
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• 2000

This paper presents a computational object model supporting CM(Continuous Media) stream interfaces including QoS(Quality of Service) required in the distributed application method for the proposed stream interface including QoS. A stream interface consists of a data channel and a control channel. In this paper, the CORBA supporting communication channel is used as the control channel and various transport protocols can be used as the dta channel of the stream interface. Also, specifications of the application QoS are included in stream interface specification. In implementation, FIFO queues and timers are used to support transmission rate, delay and jitter control mechanisms of he stream interface.