• Title/Summary/Keyword: Continuum analysis

Search Result 572, Processing Time 0.032 seconds

Dynamic Equivalent Continuum Modeling of a Box-Beam Typed Wing (Box-Beam 형상 날개의 동적 등가연속체 모델링에 관한 연구)

  • 이우식;김영수
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.17 no.11
    • /
    • pp.2704-2710
    • /
    • 1993
  • A simple and straightforward method is introduced for developing continuum beam-rod model of a box-beam typed aircraft wing with composite layered skin based on "energy equivalence." The equivalent continuum structral properties are obtained from the direct comparison of the reduced stiffness and mass matrices for box-beam typed wing with those for continuum beam-rod model. The stiffness and mass matrices are all represented in terms of the continuum degrees-of freedom defined in this paper. The finite-element method. The advantage of the present continuum method is to give every continuum structural properties including all possible coupling terms which represent the couplings between different deformations. To evaluate the continuum method developed in this paper, free vibration analyses for both continuum beam-rod and box-beam are conducted. Numerical tests show that the present continuum method gives very reliable structural and dynamic properties compared to the results by the conventional finite-element analysis. analysis.

Aeroelastic Analyses of Aircraft Wing by Using Equivalent Continuum BeamalRod Model (등가연속체 Beam-Rod 모델을 이용한 항공기 날개의 공력탄성 해석)

  • Lee, U-Sik;Lee, Hang
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.19 no.3
    • /
    • pp.615-622
    • /
    • 1995
  • It may be inefficient to conduct the aeroelastic analysis by using full-scale conventional finite-element analyses or experiments, from the initial design phase, for an aircraft wing which can be considered as the discontinuum complex structure with composite laminated skins. In this paper, therefore more efficient aeroelastic analysis has been conducted for a box-beam typed aircraft wing by using the equivalent continuum beam-rod model which is derived from the concept of energy equivalence. Equivalent structural properties of the continuum beam-rod model are obtained from the direct comparison of the finite-element matrices of continuum beam-rod model with those of box-beam typed aircraft wing. Numerical results by the continuum beam-rod model approach are compared with those by the conventional finite-element analysis approach to show that the continuum beam-rod model proposed herein is quite satisfactory as a simplified model of aircraft wing structure for aeroelastic analyses.

A Study on Application Range of Continuum Model to Discontinuous Rock mass with Numerical Analysis (불연속지반의 연속체 모델 적용범위에 대한 수치해석적 연구)

  • 이경우;노상림;윤지선
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2002.03a
    • /
    • pp.197-204
    • /
    • 2002
  • In this study, multivariate analysis based on domestic data(958 EA) of road tunnel, and suggest the easy prediction equation of Q-system. We generate applicable Q-value to numerical analysis method with using the equation and investigate the behavior as variable Q-value of rock mass induced excavation with discontinuum numerical analysis method, UDEC. In the result of the experiment, we research the application range of Q-value to apply the continuum model to discontinuous rock mass is below 0.7 and we testify the applicability of continuum model as researched Q-value with continuum numerical analysis method, FLAC.

  • PDF

Equivalent Continuum Modeling Methods for Flat Corrugated Panels (평판형 주름판넬에 대한 등가 연속체 모델링기법)

  • 이상윤;이우식
    • Journal of the Korean Society for Railway
    • /
    • v.3 no.2
    • /
    • pp.43-50
    • /
    • 2000
  • The corrugated panels are the prime candidate structure for the floor, roof and wall of Korean high speed train. The equivalent continuum modeling approach panels can be used for the efficient design and evaluation of their structural characteristics. The equivalent continuum models, derived from the true complex corrugated panels, should have the same structural behavior as the original structures have. This paper briefly reviews three representative continuum modeling methods: the static analysis method and two plate-models based on modal analysis methods (MAM). These methods are evaluated through some numerical examples by comparing the natural frequencies and static deflections. It is observed that the plate-model based on Rayleigh-Ritz method seems to provide the best results when used in conjunction with the cantilever-type boundary conditions. The equivalent elastic constants of various corrugated panels, depending on the changes in their configurations, are tabulated for efficient use in structural design.

  • PDF

Nano-continuum multi scale analysis using node deactivation techniques (절점 비활성화 기법을 적용한 나노-연속체 멀티스케일 해석 기법)

  • Rhee Seung-Yun;Cho Maeng-Hyo
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2006.04a
    • /
    • pp.395-402
    • /
    • 2006
  • In analyzing the nano-scale phenomena or behaviors of nano devices or materials, it is often desirable to deal with more atoms than can be treated only with a full atomistic simulation. However, even now, it is advisable to apply the atomistic simulation to the narrow region where the deformation field changes rapidly but to apply the conventional continuum model to the region far from that region. This equivalent continuum model can be formulated by applying the Cauchy-Born rule to the exact atomistic potential as in the quasicontinuum method. To couple the atomistic model with the equivalent continuum model, continuum displacements are conformed to the molecular displacements at the discrete positions of the atoms within the bridging domain. To satisfy the coupling constraints, we apply the Lagrange multiplier method. The continuum model in the bridging model should be applied on the region where the deformation field changes gradually. Then we can make the nodal spacing in the continuum model be much larger than the atomic spacing. In the first step, we generate the atomic-resolution mesh with the nodal spacing equal to the atomic spacing, and then we eliminate the nodal degrees of freedom adaptively using the node deactivation techniques. We eliminate more DOFs as the regions are more far from the atomistic region. Computing time and computational resources can be greatly reduced by the present node deactivation technique in multi scale analysis.

  • PDF

Continuum Modeling and dynamic Analysis of Platelike Truss Structures (평판형 트러스구조물의 연속체 모델링 및 동적해석)

  • 이우식;김종윤
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.16 no.6
    • /
    • pp.1021-1029
    • /
    • 1992
  • A rational and straightforward method is introduced for developing continuum models of large platelike periodic lattice structures based on energy equivalence. The procedure for developing continuum plate models involves the use of existing well-defined finite element matrices for the easy calculation of strain and kinetic energies of a repeating cell, from which the reduced stiffness and mass matrices are obtained in terms of continuum degrees- of-freedom defined in this paper. The equivalent continuum plate properties are obtained from the direct comparison of the reduced matrices for continuum plate with those for lattice plate. The advantages of the present continuum method are that it may be applied to arbitrary lattice configurations and may give most diverse equivalent continuum plate properties including all kinds of coupling, while other methods may give only limited structural properties. To evaluate the continuum method developed in this paper, free vibration analyses for both of continuum and lattice plates are conducted. Numerical results show that the present continuum method gives very reliable structural and dynamic properties compared to other well-recognized methods.

A Study on the Information Continuum Model: Preliminary Analysis to Establish the Relationship Between Records and Information (정보 컨티뉴엄 모델에 관한 연구: 기록과 정보 간의 관계 정립을 위한 예비적 분석)

  • Kim, Myoung-hun
    • Journal of Korean Society of Archives and Records Management
    • /
    • v.22 no.3
    • /
    • pp.21-36
    • /
    • 2022
  • This study intends to analyze the information continuum model as part of establishing the relationship between records and information. The information continuum is a theoretical system designed to establish a new information concept from the record-keeping point of view based on the record continuum. It provides a conceptual framework that can identify the elements for information management that exist in record-keeping. Accordingly, in Chapter 2, the background and process of the information continuum development, which followed after the record continuum development, were reviewed. Then, the concept of information established by borrowing information science theory was examined in relation to the record continuum. In Chapter 3, the conceptual structure of the information continuum and the purpose and method of information utilization were considered. Afterward, the four dimensions and attributes that structurally schematize the elements for information management in record-keeping were analyzed. Based on this analysis, Chapter 4 tried to present the meaning and limitations of the information continuum.

Seismic analysis of steel structure with brace configuration using topology optimization

  • Qiao, Shengfang;Han, Xiaolei;Zhou, Kemin;Ji, Jing
    • Steel and Composite Structures
    • /
    • v.21 no.3
    • /
    • pp.501-515
    • /
    • 2016
  • Seismic analysis for steel frame structure with brace configuration using topology optimization based on truss-like material model is studied. The initial design domain for topology optimization is determined according to original steel frame structure and filled with truss-like members. Hence the initial truss-like continuum is established. The densities and orientation of truss-like members at any point are taken as design variables in finite element analysis. The topology optimization problem of least-weight truss-like continuum with stress constraints is solved. The orientations and densities of members in truss-like continuum are optimized and updated by fully-stressed criterion in every iteration. The optimized truss-like continuum is founded after finite element analysis is finished. The optimal bracing system is established based on optimized truss-like continuum without numerical instability. Seismic performance for steel frame structures is derived using dynamic time-history analysis. A numerical example shows the advantage for frame structures with brace configuration using topology optimization in seismic performance.

A Study on Rolling Contact Fatigue of Rail by Damage Mechanics (손상역학에 의한 레일의 구름접촉피로 연구)

  • Kang, Sung-Soo
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.32 no.6
    • /
    • pp.931-937
    • /
    • 2008
  • The rail/wheel rolling contact affects the microstructure in the surface layer of rail. Recently. continuum damage mechanics allows us to describe the microprocesses involved during the straining of materials and structures at the macroscale. Elastic and plastic strains. the corresponding hardening effects are generally accepted to be represented by global continuum variables. The purpose of continuum damage mechanics is to introduce the possibility of describing the coupling effects between damage processes and the stress-strain behavior of materials. In this study. the continuum damage mechanics caused by elastic deformation was briefly introduced and applied to the fatigue damage of the rails under the condition of cyclic loading. The material parameter for damage analysis was first determined so that it could reproduce the life span under the compressive loading in the vicinity of fatigue limit. Some numerical studies have been conducted to show the validity of the present computational mechanics analysis.

Significance and Limitations of Record Continuum in Electronic Record Environment: Focusing on Meaning and Nature of Records (전자기록 환경에서 레코드 컨티뉴엄의 의의와 한계: 기록의 의미 및 속성을 중심으로)

  • Kim, Myoung-hun
    • Journal of Korean Society of Archives and Records Management
    • /
    • v.21 no.3
    • /
    • pp.1-16
    • /
    • 2021
  • Record continuum is a theory providing the basis for archival science in the paradigm shift to the electronic record environment. However, critical analysis of it has been hardly performed so far, as it is still in development, and its core is a new perspective on records different from the life cycle model. Therefore, for further understanding of the significance and limitations of record continuum in the electronic record environment and performance of more in-depth theoretical development, an analysis of the meaning and nature of records contained in record continuum logic is essential. Given that record continuum does not define a record separately, the meaning and nature of records it contains in the recent electronic record environment are examined through the analysis of axis and dimension in a record continuum model.