• Journal of Korean Association for Spatial Structures
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• v.1 no.2 s.2
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• pp.59-66
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• 2001

This paper describes three modules for development of the Space Frame Integrated Design System(SFIDS). The Control Module is implemented to control the developed system. The Model Generation Module based on PATRAN user interface enables users to generate a complicated finite element model for space frame structures. The Optimum Design Module base on a branch of combinatorial optimization techniques which can realize the optimization of a structure having a large number of members designs optimum members of a space frame after evaluating analysis results. The Control Module and the Model Generation Module Is implemented by PATRAN Command Language(PCL) while C++ language is used in the Optimum Design Module. The core of the system is PATRAN database, in which the Model Generation Module creates information of a finite element model. Then, PATRAN creates Input files needed for the analysis program from the information of the finite element model in the database, and in turn, imports output results of analysis program to the database. Finally, the Optimum Design Module processes member grouping of a space frame based on the output results, and performs optimal member selection of a space frame. This process is repeated until the desired optimum structural members are obtained.

• International journal of steel structures
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• v.18 no.4
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• pp.1464-1469
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• 2018

Steel frames with ductile connections have good seismic performance under strong earthquake, they are now popular for high seismic design. In order to simplify the process of numerical analysis of the steel frames with ductile connections, simplified connection models are introduced, two types of springs are placed in the simplified connection model, which can simulate deformation of the panel zone and members. 6-story-3-bay steel frames with ductile connections are simplified and carried out modal analysis, fundamental periods of the frames predicted by finite-element analysis for simplified steel frame models were compared to the results for actual frame models. 2-story steel frame with reduced beam section connections is simplified and carried out pseudo-static analysis, hysteretic curves and skeleton curves of the frame obtained by finite-element analysis for simplified steel frame model are compared to test results. The comparison show that the difference between them is small, it is reliable and effective to predict mechanical properties of the steel frame with ductile connection by finite-element analysis of simplified steel frame model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.9-17
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• 2013

In this study, an efficient analytical model for the dynamic analysis of tall buildings with a shear wall-frame structural system has been proposed. A shear wall-frame structural system usually consists of a core wall showing flexural behavior and a frame presenting shear behavior. Therefore, the deformed shape of the shear wall-frame structural system is shown by the combination of flexural mode and shear mode. These characteristics should be considered when an efficient analytical model is developed. To this end, the effect of shear wall and frame on the dynamic behavior of a tall building with a dual system has been separately investigated. In this study, the structural characteristics of a separated individual shear wall model and the frame model without shear wall has been evaluated. In order to consider the effect of the shear wall in the frame model without shear wall, a rigid body was used instead of the shear wall. Each equivalent model for the separated shear wall part and frame part has been independently developed and two equivalent models were then combined to create an efficient analytical model for tall buildings with a shear wall-frame structural system. In order to verify the efficiency and accuracy of the proposed method, time history analyses of tall buildings with a shear wall-frame system were performed. Based on analytical results, it has been confirmed that the proposed method can provide accurate results, requiring significantly reduced computational time and memory.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.830-835
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• 2007

In this paper, stress analyses using shell and solid elements on weld zone of railway bogie frame were performed. To calculate stress distribution on weld zone, a coupling model using shell and solid elements was suggested. For this purpose, we performed specimen analyses on T-type solid and shell model of T-type panels which were modeled using shell elements, solid elements and coupled elements, respectively. The result showed that the stress concentration at weld zone was occurred in solid model, but it didn't occur in shell model. And the stress distribution of coupled model was similar to that of solid model. Also, we applied the coupled modeling method on the analysis on weld zone of bogie frame. The stress distribution of coupled model showed much higher compared to that of shell only model. Therefore, the coupled model method is highly recommended for the stress analysis in weld zone of bogie frame.

• Steel and Composite Structures
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• v.19 no.5
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• pp.1055-1075
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• 2015

In order to investigate the accuracy and applicability of steel equivalent constitutive model, the calculated results were compared with typical tests of steel frames under static and dynamic loading patterns firstly. Secondly, four widely used models for time history analysis of steel frames were compared to discuss the applicability and efficiency of different methods, including shell element model, multi-scale model, equivalent constitutive model (ECM) and traditional beam element model (especially bilinear model). Four-story steel frame models of above-mentioned finite element methods were established. The structural deformation, failure modes and the computational efficiency of different models were compared. Finally, the equivalent constitutive model was applied in seismic incremental dynamic analysis of a ten-floor steel frame and compared with the cyclic hardening model without considering damage and degradation. Meanwhile, the effects of damage and degradation on the seismic performance of steel frame were discussed in depth. The analysis results showed that: damages would lead to larger deformations. Therefore, when the calculated results of steel structures subjected to rare earthquake without considering damage were close to the collapse limit, the actual story drift of structure might already exceed the limit, leading to a certain security risk. ECM could simulate the damage and degradation behaviors of steel structures more accurately, and improve the calculation accuracy of traditional beam element model with acceptable computational efficiency.

• Journal of the Korea Society of Computer and Information
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• v.23 no.9
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• pp.43-50
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• 2018

In this paper, we propose a hexagon model-based efficient beacon frame scheduling approach for wireless sensor networks. The existing beacon frame scheduling approaches use a lot of slots and subslots for the beacon frame scheduling. Thus, the data from source nodes are not efficiently delivered to a sink node. Also in case a sink node needs to broadcast a beacon frame to the nodes in the network, delivering the beacon frame to the network nodes is not efficient as well. Thus, to solve the problem, we use a hexagon model to find the number of slots and subslots for the beacon frame scheduling. By using them for the beacon frame scheduling, the proposed approach performs better than other approaches in terms of the data transmission delay, the number of received data, the beacon transmission delay and the number of relaying the beacon frames.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.107-113
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• 1998

Grinding operation has difficulty in satisfying the qualitative knowledge based on the skilful expert as well as the quantitative data for all user. Design of grinding database based on the frame-based model is more effective method for utilizing the empirical and qualitative knowledge. In this paper. basic strategy to develop the grinding database by taking frame-based model, which is strongly dependent upon experience and intuition, is described. Grinding database based on the frame based model for designing the interaction and inference among the slots is accomplised by the object-oriented paradigm system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.10 s.103
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• pp.1202-1210
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• 2005

This paper develops a computer model for estimating the bump characterisitcs of a cat)over type large-sized truck. The truck is composed of front and rear suspension systems, a frame, a cab, and ten tires. The computer model is developed using MSC.ADAMS. A shock absorber, a rubber bush, and a leaf spring affect a lot on the dynamic characteristic of the vehicle. Their stiffness and damping coefficient are measured and used as input data of the computer model. Leaf springs in the front and rear suspension systems are modeled by dividing them three links and joining them with joints. To improve the reliability of the developed computer model, the frame is considered as a flexible body. Thus, the frame is modeled by finite elements using MSC.PATRAN. A mode analysis is performed with the frame model using MSC.NASTRAN in order to link the frame model to the computer model. To verify the reliability of the developed computer model, a double wheel bump test is performed with an actual vehicle. In the double wheel bump, vortical displacement, velocity, acceleration are measured. Those test results are compared with the simulation results.

• The Journal of the Acoustical Society of Korea
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• v.31 no.2
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• pp.93-99
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• 2012

For speech coding, a vocal tract is modeled using Linear Predictive Coding (LPC) coefficients. The LPC coefficients are typically transformed to Line Spectral Frequency (LSF) parameters which are advantageous for linear interpolation and quantization. If multidimensional LSF data are quantized directly using Vector-Quantization (VQ), high rate-distortion performance can be obtained by fully utilizing intra-frame correlation. In practice, since this direct VQ system cannot be used due to high computational complexity and memory requirement, Split VQ (SVQ) is used where a multidimensional vector is split into multilple sub-vectors for quantization. The LSF parameters also have high inter-frame correlation, and thus Predictive SVQ (PSVQ) is utilized. PSVQ provides better rate-distortion performance than SVQ. In this paper, to implement the optimal predictors in PSVQ for voice storage devices, we propose Multi-Frame AR-model based SVQ (MF-AR-SVQ) that considers the inter-frame correlations with multiple previous frames. Compared with conventional PSVQ, the proposed MF-AR-SVQ provides 1 bit gain in terms of spectral distortion without significant increase in complexity and memory requirement.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.210-215
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• 1998

To design a space frame structure by the conventional method is not easy in practical sense since it is generally a three-dimensional complicated form, and stability and nonlinear problems are not easily checked in the design process. This paper describes two modules, the Model Generator which is based on PATRAN user interface that enables users to generate a complicated finite element model; the Optimum Design Module which analyzes output results of analysis program, and designs members of a space frame. The Model Generator is based on PCL while C++ language is used in the Optimum Design Module. Structural analysis is performed by using ABAQUS. All of these modules constitute Space Frame Integrated Design System. The Core of the system is PATRAN database, in which the Model Generator creates information of a finite element model. Then, PATRAN creates input files needed for the analysis program from the information of the finite element model in the database, and in turn, imports output results of analysis program to the database. Finally, the Optimum Design Module processes member grouping of a space frame based on the output results, and performs optimal member selection of a space frame. This process is repeated until the desired optimum structural members are obtained.