• Title/Summary/Keyword: Co-rotational 이론

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Development of Nonlinear Triangular Planar Element Based on Co-rotational Framework (Co-rotational 이론 기반 비선형 삼각평면 유한요소의 개발)

  • Cho, Hae-Seong;Shin, Sang-Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.5
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    • pp.485-490
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    • 2015
  • This paper presents development of a geometrically nonlinear triangular planar element including rotational degrees of freedom, based on the co-rotational(CR) formulation. The CR formulation is one of the efficient geometrically nonlinear formulations and it is based on the assumptions on small strain and large rotation. In this paper, modified CR formulation is suggested for the developemnt of a triangular planar element. The present development is validated regarding the static and time transient problems. The present results are compared with the results predicted by the previous researchers and those obtained by the existing commercial software.

Development of Nine-node Co-rotational Planar Element for Elastoplastic/Contact Analysis (탄소성/접촉 해석을 위한 Co-rotational 정식화 기반의 9절점 평면 요소 개발)

  • Cho, Hae-Seong;Joo, Hyun-Shig;Shin, Sang Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.1
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    • pp.1-6
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    • 2017
  • This paper presents development of the nine-node co-rotational(CR) planar element applicable for elastoplastic and contact analysis. The CR formulation is one of the efficient geometrically nonlinear formulations. It is based on the assumptions of small strain and large displacement. Further, it is extended to both elastoplastic analysis and contact analysis in this paper. For accurate plastic analysis, nine-node quadrilateral element, which can provide accurate stress prediction, is chosen. Bi-linear hardening rule based on Newton- Raphson return-mapping is employed. Also, Lagrange multiplier is used in order for constraints regarding the contact analysis. The present development is validated via the time transient problems. The present results are compared with those obtained by the other existing software.

Study on Cantilever Beam Tip Response with Various Harmonic Frequencies by Using EDISON Co-rotational Plane Beam-Dynamic Tip Load (EDISON Co-rotational Plane Beam-Dynamic Tip Load를 이용한 가진주파수 변화에 따른 외팔보의 자유단 진동 연구)

  • Park, Chul-Woo;Joo, Hyun-Shig;Ryu, Han-Yeol;Shin, Sang-Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.5
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    • pp.477-483
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    • 2015
  • In this paper, Euler-Bernoulli beam theories(EB-beam) are used, and Fast Fourier Transformation(FFT) analysis is then employed to extract their natural frequencies using both analytical approach and Co-rotational plane beam(CR-beam) EDISON program. EB-beam is used to analyze a spring-mass system with a single degree of freedom. Sinusoidal force with various frequencies and constant magnitude are applied to tip of each beam. After the oscillatory tip response is observed in EB-beam, it decreases and finally converges to the so-called 'steady-state.' The decreasing rate of the tip deflection with respect to time is reduced when the forcing frequency is increased. Although the tip deflection is found to be independent of the excitation frequency, it turns out that time to reach the steady state response is dependent on the forcing frequency.

Computational Algorithm for Nonlinear Large-scale/Multibody Structural Analysis Based on Co-rotational Formulation with FETI-local Method (Co-rotational 비선형 정식화 및 FETI-local 기법을 결합한 비선형 대용량/다물체 구조 해석 알고리듬 개발)

  • Cho, Haeseong;Joo, HyunShig;Lee, Younghun;Gwak, Min-cheol;Shin, SangJoon;Yoh, Jack J.
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.9
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    • pp.775-780
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    • 2016
  • In this paper, a computational algorithm of an improved and versatile structural analysis applicable for large-size flexible nonlinear structures is developed. In more detail, nonlinear finite element based on the co-rotational (CR) framework is developed. Then, a finite element tearing and interconnecting method using local Lagrange multipliers (FETI-local) is combined with the nonlinear CR finite element. The resulting computational algorithm is presented and applied for nonlinear static analyses, i.e., cantilevered beam and multibody structure. Finally, the proposed analysis is evaluated with regard to its parallel computation performance, and it is compared with those obtained by serial computation using the sparse matrix linear solver, PARDISO.

Optimum Design of the Drone Single Arm Using Co-rotational Plane Beam-Dynamic Tip Load (Co-rotational Plane Beam-Dynamic Tip Load를 이용한 Drone Single Arm의 최적 설계)

  • Park, SunHoo;Lee, SangGu;Shin, SangJoon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.10
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    • pp.825-835
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    • 2017
  • This paper aims to build a drone platform based on an optimum design of its single arm. Its single arm is assumed as a cantilevered beam with a tip mass. Based on the numerical optimization theory, validation and optimization of a new design is conducted by comparing the results with the similar ones obtained by ANSYS. Finally, this design is reflected in the control simulation, and the requirement of an optimum structural design considering the resonance situation is satisfied.

Linear Analysis and Non-linear Analysis with Co-Rotational Formulation for a Cantilevered Beam under Static/Dynamic Tip Loads (정적 및 동적 하중을 받는 외팔보 거동에 관한 선형 및 CR 정식화 비선형 예측의 비교)

  • Ko, Jeong-Woo;Bin, Young-Bin;Eun, Won-Jong;Shin, Sang-Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.5
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    • pp.467-475
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    • 2015
  • In this paper, the behaviour of a cantilevered beam was predicted to examine the difference between linear and non-linear static, dynamic analysis for a structure by using CR nonlinear formulation. Then, external transverse static and dynamic loads were applied at the free tip of the beam. Classical theories were used for the present linear analysis and co-rotational dynamic FEM program was used for the present nonlinear analysis. In the static analysis, effects of the load for the beam deflection were observed in both linear and nonlinear analysis. Then, normalized displacement at the tip of the beam was predicted for different frequency ratio and a significant difference was obtained in the vicinity of the resonant frequency. In addition, effects of frequency and time for the beam deflection were investigated to find the frequency delay.

Nonlinear Shell Finite Element and Parallel Computing Algorithm for Aircraft Wing-box Structural Analysis (항공기 Wing-box 구조해석을 위한 비선형 쉘 유한요소 및 병렬계산 기법 개발)

  • Kim, Hyejin;Kim, Seonghwan;Hong, Jiwoo;Cho, Haeseong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.8
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    • pp.565-571
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    • 2020
  • In this paper, precision and efficient nonlinear structural analysis for the aircraft wing-box model is developed. Herein, nonlinear shell element based on the co-rotational (CR) formulation is implemented. Then, parallel computing algorithm, the element-based partitioning technique is developed to accelerate the computational efficiency of the nonlinear structural analysis. Finally, computational performance, i.e., accuracy and efficiency, of the proposed analysis is evaluated by comparing with that of the existing commercial software.

A General and Versatile XFINAS 4-node Co-Rotational Resultant Shell Element for Large Deformation Inelastic Analysis of Structures (구조물의 대변형 비탄성 해석을 위한 범용 목적의 XFINAS 4절점 순수 변위 합응력 쉘요소)

  • Kim, Ki Du;Lee, Chang Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.3A
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    • pp.447-455
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    • 2006
  • A general purpose of 4-node co-rotational resultant shell element is developed for the solution of nonlinear problems of reinforced concrete, steel and fiber-reinforced composite structures. The formulation of the geometrical stiffness presented here is defined on the mid-surface by using the second order kinematic relations and is efficient for analyzing thick plates and shells by incorporating bending moment and transverse shear resultant forces. The present element is free of shear locking behavior by using the ANS (Assumed Natural Strain) method such that the element performs very well as thin shells. Inelastic behaviour of concrete material is based on the plasticity with strain hardening and elasto-plastic fracture model. The plasticity of steel is based on Von-Mises Yield and Ivanov Yield criteria with strain hardening. The transverse shear stiffness of laminate composite is defined by an equilibrium approach instead of using the shear correction factor. The proposed formulation is computationally efficient and versitile for most civil engineering application and the test results showed good agreement.

Spatial Post-buckling Analysis of Thin-walled Space Frames based on the Corotational Formulation (대회전을 고려한 공간 박벽 뼈대구조물의 기하 비선형 후좌굴 거동 해석)

  • Lee, Kyoung Chan;Park, Jung Il;Kim, Sung Bo;Chang, Sung Pil
    • Journal of Korean Society of Steel Construction
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    • v.19 no.6
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    • pp.599-610
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    • 2007
  • In this paper, we described a co-rotational formulation for the geometrical nonlinear analysis of three-dimensional frames. We suggested a new concept called the Zero-Twist-Section Condition (ZTSC) to decide the element coordinate system consistently. According to the ZTSC procedure, it is possible to obtain an element coordinate system and natural deformations consistently when finite displacements and rotations are induced in an element. Based on the developed procedure, numerical examples are investigated to calculate natural rotations while finite displacements are imposed on an element. Also, the developed co-rotational procedure gives accurate results in the analysis of post-buckling problems with finite rotations.

Prediction of Vibration Characteristics of a Composite Rotor Blade via Deep Neural Networks (심층신경망을 이용한 복합재 로터 블레이드의 진동특성 예측)

  • Yoo, Seungho;Jeong, Inho;Kim, Hyejin;Cho, Haeseong;Kim, Taejoo;Kee, Youngjung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.5
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    • pp.317-323
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    • 2022
  • In this paper, a deep neural network(DNN) model for predicting the vibration characteristics of the composite rotor blade with c-spar cross section was developed. Herein, the present DNN model is defined by using the natural frequencies obtained through the in-house code based on the nonlinear co-rotational(CR) shell element. For the present DNN model, the accuracy of the model was evaluated via the data with a random distribution of thickness and a tendency to decrease in thickness along the blade span.