• 소음진동
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• 제8권2호
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• pp.361-368
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• 1998

Complex and large lattice type structures are frequently used in design of bridge, tower, crane and aerospace structures. In general, in order to analyze these structures we have used the finite element method(FEM). This method is the most widely used and powerful tool for structural analysis. However, it is necessary to use a large amount of computer memory and computation time because the FEM resuires many degrees of freedom for solving dynamic problems exactly for these complex and large structures. For overcoming this problem, the authors developed the transfer stiffness coefficient method(TSCM). This method is based on the concept of the transfer of the nodal dynamic stiffness coefficient which is related to force and displacement vector at each node. In this paper, the authors formulate vibration analysis algorithm for a complex and large lattice type structure using the transfer of the nodal dynamic stiffness coefficient. And we confirmed the validity of TSCM through numerical computational and experimental results for a lattice type structure.

• 소음진동
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• 제8권5호
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• pp.949-956
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• 1998

Complex and large lattice type structures are frequently used in design of bridge, tower, crane and aerospace structures. In general, in order to analyze these structures we have used the finite element method(FEM). This method is the most widely used and powerful method for structural analysis lately. However, it is necessary to use a large amount of computer memory and computational time because the FEM requires many degrees of freedom for solving dynamic problems exactly for these complex and large structures. For analyzing these structures on a personal computer, the authors developed the transfer stiffness coefficient method(TSCM). This method is based on the concept of the transfer of the nodal dynamic stiffness coefficient matrix which is related to force and displacement vector at each node. And we suggested TSCM for free vibration analysis of complex and large lattice type structures in the previous report. In this paper, we formulate forced vibration analysis algorithm for complex and large lattice type structures using extened TSCM. And we confirmed the validity of TSCM through computational results by the FEM and TSCM, and experimental results for lattice type structures with harmonic excitation.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.307-311
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• 2011

이 논문은 필라멘트 와인딩 공법으로 제작된 cone형 복합재 lattice 구조물에 대한 연구이다. cone형 복합재 lattice 구조물은 helical rib과 hoop rib 구조로 이루어져 있다. 이 구조는 탄소 섬유를 에폭시수지에 함침 시켜 섬유의 끊어짐이 없이 연속적으로 실리콘 고무 금형의 홈 안에 필라멘트 와인딩 하여 제작한 것이다. 본 연구에서 cone형 복합재 lattice 구조물에 대한 설계 개념과 제작방법에 대해 기술하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.190-195
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• 1997

Recently it is increased by degrees to construct complex or large lattice type structures such as bridges, towers, cranes, and structures that can be used for space technology. In general, in order to analyze, these structures we have used the finite element method(FEM). In this method, however, it is necessary to use a large amount of computer memory and computation time because the FEM requires many degrees of freedom for solving dynamic problems for these structures. For overcoming this problem, the authors have developed the transfer dynamic stiffness coefficient method(TDSCM). This method is based on the concepts of the transfer and the synthesis of the dynamic stiffness coefficient which is related to force and displacement vector at each node. In this paper, the authors formulate vibration analysis algorithm for a complex and large lattice type structure using the transfer of the dynamic stiffness coefficient. And the validity of TDSCM demonstrated through numerical computational and experimental results.

• Composites Research
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• 제31권4호
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• pp.156-160
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• 2018

본 논문에서는 콘형 복합재 격자구조체의 구조안전성 평가 기법에 대해 연구를 수행하였다. 콘형 복합재격자구조체의 구조안전성 평가는 유한요소해석을 통해 수행되었다. 구조안전성 평가를 위한 유한요소모델은 솔리드 요소를 사용하여 생성하였다. 섬유 교차부와 비교차부의 물성 차이를 고려하기 위해 섬유 체적률을 고려한 기계적 물성을 적용하였다. 구조해석 기법의 검증을 위해 콘형 복합재 격자구조체의 압축 시험을 수행하였다. 시험과 해석의 비교 결과, 약 2%의 변위 오차가 발생하여 잘 일치하는 것을 확인하였다.

• 한국공간구조학회논문집
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• 제23권4호
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• pp.27-34
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• 2023

In this study, the seismic response characteristics of the three analysis model with or without TMD were investigated to find out the effective dome shape. The three analysis models are rib type, lattice type and geodesic type dome structure composed of space frame. The maximum vertical and horizontal displacements were evaluated at 1/4 point of the span by applying the resonance harmonic load and historical earthquake loads (El Centro, Kobe, Northridge earthquakes). The study of the effective TMD installation position for the dome structure shows that seismic response control was effective when eight TMDs were installed in all types of analysis model. The investigation of the efficiency of TMD according to dome shape presents that lattice dome and geodesic dome show excellent control performance, while rib dome shows different control performance depending on the historical seismic loads. Therefore, lattice and geodesic types are desirable for seismic response reduction using TMD compared to rib type.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.169-175
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• 1997

Recently it is increased by degrees to produce complex and large lattice structures such as bridge, tower, crane, and space structures. In general, in order to analyse these structures we have used finite element method(FEM). In this method, however, it is necessary to use a large amount of computer memory and to take long computation time. For overcoming this problem, the Authors have developed the transfer dynamic stiffness coefficient method(TDSCM) which consists on the concept of the substructure synthesis method and transfer influence coefficient method. In this paper, the new free vibration analysis method for large type lattice structure is formulated by the TDSCM. And the results obtained by TDSCM are compared with those obtained by FEM, transfer matrix method and experiment. And it is confirmed for TDSCM to be the numerical high accuracy and high speed structure analysis method.

• 한국공간구조학회논문집
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• 제3권2호
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• pp.69-75
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• 2003

In case of rectangular lattice dome which shearing rigidity is very small, it has a concern to drop Buckling strength considerably by external force. So, by means of system to increase buckling-strength, there is a method of construction that lattice of dome is one with roof material. In a case like this, shearing rigidity of roof material increases buckling-strength of the whole of structure and can be designed economically from the viewpoint of practice. In case of analysis is achieved considering roof material that adheres to lattice of dame, there is method that considers the rigidity that use effective width frame as method to evaluate rigidity of roof material. therefore, this study is aimed at deciding effective width of roof material united with rectangular lattice dome to evaluate rigidity of roof material by effective width of frame and investigating how much does rigidity of roof material united with lattice of dome increase buckling-strength of the whole of structure according to rise-ratio. Conditions of loading are vertical-type-uniform loading. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems.

• Advances in aircraft and spacecraft science
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• 제9권5호
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• pp.377-400
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• 2022

The aim of this work is a numerical comparison (FEM) between lattice pyramidal-core panel and honeycomb core panel for different core thicknesses. By evaluating the mid-span deflection, the shear rigidity and the shear modulus for both core types and different core thicknesses, it is possible to define which core type has got the best mechanical behaviour for each thickness and the evolution of that behaviour as far as the thickness increases. Since a specific base geometry has been used for the lattice pyramidal core, the comparison gives us the opportunity to investigate the unit cell strut angle giving the higher mechanical properties. The presented work considers a detailed FEM modelling of a standard 3-point bending test (ASTM C393/C393M Standard Practice). Detailed FEM modelling addresses to detailed discretization of cores by means of beam elements for lattice core and shell elements for honeycomb core. Facings, instead, have been modelled by using shell elements for both sandwich panels. On lattice core structure, elements of core and facings are directly connected, to better simulate the additive manufacturing process. Otherwise, an MPC-based constraint between facings and core has been used for honeycomb core structure. Both sandwich panels are entirely built of Aluminium alloy. Prior to compare the two models, the FEM sandwich panel model with lattice pyramidal core needs to be validated with 3-point bending test experimental results, in order to ensure a good reliability of the FEM approach and of the comparison. Furthermore, the analytical validation has been performed according to Allen's theory. The FEM analysis is linear static with an increasing midspan load ranging from 50N up to 500N.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.170-173
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• 2003

In this paper, we proposed a new bulk LDMOS structure which can be used for RF application, and its fabrication steps were introduced. The simulated devices consist of three types: Bulk device, SLB(SOI Like Bulk), and SOI device. As a result of process and device simulation, we showed electrical characteristics, such as threshold voltage, subthreshold slope, DIBL(Drain Induced Barrier Lowering), off-state current, and breakdown voltage. In this simulation study, the lattice temperature model was adopted to see the device characteristics with lattice temperature during the operation. SLB device structure showed the best breakdown characteristics among the other structures. The breakdown voltage of SLB structure is about 9V, that of bulk is 7V, and that of SOI is 8V.