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The finite element model research of the pre-twisted thin-walled beam

  • Chen, Chang Hong;Zhu, Yan Fei;Yao, Yao;Huang, Ying
    • Structural Engineering and Mechanics
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    • v.57 no.3
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    • pp.389-402
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    • 2016
  • Based on the traditional mechanical model of thin-walled straight beam, the paper makes analysis and research on the pre-twisted thin-walled beam finite element numerical model. Firstly, based on the geometric deformation differential relationship, the Saint-Venant warping strain of pre-twisted thin-walled beam is deduced. According to the traditional thin-walled straight beam finite element mechanical model, the finite element stiffness matrix considering the Saint-Venant warping deformations is established. At the same time, the paper establishes the element stiffness matrix of the pre-twisted thin-walled beam based on the classic Vlasov Theory. Finally, by calculating the pre-twisted beam with elliptical section and I cross section and contrasting three-dimensional solid finite element using ANSYS, the comparison analysis results show that pre-twisted thin-walled beam element stiffness matrix has good accuracy.

Theoretical analysis of Y-shape bridge and application

  • Lu, Peng-Zhen;Zhang, Jun-Ping;Zhao, Ren-Da;Huang, Hai-Yun
    • Structural Engineering and Mechanics
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    • v.31 no.2
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    • pp.137-152
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    • 2009
  • Mechanic behavior of Y-shape thin-walled box girder bridge structure is complex, so one can not exactly hold the mechanical behavior of the Y-shape thin-walled box girder bridge structure through general calculation theory and analytical method. To hold the mechanical behavior better, based on elementary beam theory, by increasing the degree of freedom analytical method, taking account of restrained torsiondistortion angledistortion warp and shearing lag effect at the same time, authors obtain a thin-walled box beam analytical element of 10 degrees of freedom of every node, derive stiffness matrix of the element, and code a finite element procedure. In addition, authors combine the obtained procedure with spatial grillage analytical method, meanwhile, they build a new analytical method that is the spatial thin-walled box girder element grillage analysis method. In order to validate the precision of the obtained analysis method, authors analyze a type Y-shape thin-walled box girder bridge structure according to the elementary beam theory analytical method, the shell theory analytical method and the spatial thin-walled box girder element grillage analysis method respectively. At last, authors test a type Y-shape thin-walled box girder bridge structure. Comparisons of the results of theory analysis with the experimental text show that the spatial thin-walled box girder element grillage analysis method is simple and exact. The research results are helpful for the knowledge of the mechanics property of these Y-shape thin-walled box girder bridge structures.

Free Vibration Analysis of a T Joint Using Thin-Walled Beam and Shell Elements (박판보 요소와 셸 요소를 이용한 T 조인트 진동 해석)

  • Kim, Jin-Hong;Kim, Hyeon-Seok;Kim, Yun-Yeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.9
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    • pp.2334-2343
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    • 2000
  • This paper proposes an efficient beam-shell modeling technique for the free vibration analysis of a T-joint thin-walled beam structure. Except a small portion of a T-joint which is modeled by shell elements, the structure is modeled by thin-walled beam elements that can describe warping and distortion. In order to match the shell and thin-walled beam elements at the interface of the dissimilar elements, a technique based on a pseudo inverse matrix is formulated. This paper also examines the role of the thin-walled element taking into account the distortion and warping deformation degrees of freedom in predicting accurately the dynamic characteristics of a T-joint thin-walled structure.

Shape Optimization Technique for Thin Walled Beam of Automotive Structures Considering Vibration

  • Lee, Sang-Beom;Yim, Hong-Jae;Pyun, Sung-Don
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.2E
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    • pp.63-70
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    • 2002
  • In this paper, an optimization technique for thin walled beams of vehicle body structure is proposed. Stiffness of thin walled beam structure is characterized by the thickness and typical section shape of the beam structure. Approximate functions for the section properties such as area, area moment of inertia, and torsional constant are derived by using the response surface method. The approximate functions can be used for the optimal design of the vehicle body that consists of complicated thin walled beams. A passenger car body structure is optimized to demonstrate the proposed technique.

A Study of Injection Mold Manufacturing for Ultra-Thin Walled Plate (초박판 사출성형특성 분석을 위한 금형제작에 관한 연구)

  • Lee, Sung-Hee;Ko, Young-Bae;Lee, Jong-Won;Kim, Sung-Kyu;Yang, Jin-Suk;Heo, Young-Moo
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.2 no.5
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    • pp.11-15
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    • 2008
  • A micro-injection mold for ultra-thin-walled plate was considered in this work. The proposed mold system is for the fabrication of ultra-thin walled plastic plate with micro features by injection molding. As the injection molding of thin-walled plastic, which has the thickness under $400{\mu}m$, itself is not easy, the injection molding of the micro-features in the thin-walled structure is more complicated and difficult. To investigate the basic phenomenon of the ultra-thin walled part during the injection molding process, design of the part and mold system were performed in the present study. The injection molding and structural analysis of the suggested part and mold system were also performed. Consequently, injection molding system for ultra-thin walled plate with micro features were manufactured and presented.

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Lateral Buckling Analysis of Open Section Composite Laminated Beam Under End-Moment (단모멘트를 받는 개단면 박벽 복합재 보의 횡좌굴 해석)

  • 김만호;신동구
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.51-58
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    • 2000
  • Lateral buckling behavior of laminated composite thin-walled I-section beams subjected to bending moment is investigated by applying the nonlinear anisotropic thin-walled beam theory. The constituent laminated thin-walled elements of I-section are assumed to be symmetrically laminated. The bending, twisting, and warping stiffnesses of the cross section are obtained based on the definitions of these stiffnesses In the thin-walled anisotropic beam theory In numerical examples, singly-symmetric I-beams with specially orthotropic, quasi-isotropic, angle-plys and various boundary conditions are considered. To validate the proposed theoretical approach, present analytical solutions are compared with three dimensional finite element solutions.

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Rapid Manufacturing of Microscale Thin-walled Structures using a Phase Change Work-holding Method

  • Shin Bo-Sung;Yang Dong-Yol
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.3
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    • pp.47-50
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    • 2006
  • High-speed machining is a very useful tool and one of the most effective rapid manufacturing processes. This study sought to produce various high-speed machining materials with excellent quality and dimensional accuracy. However, high-speed machining is not suitable for microscale thin-walled structures because the structure stiffness lacks the ability to resist the cutting force. This paper proposes a new method that is able to rapidly produce very thin-walled structures. This method consists of high-speed machining followed by filling. A strong work-holding force results from the solidification of the filling materials. Low-melting point metal alloys are used to minimize the thermal effects during phase changes and to hold the arbitrarily shaped thin-walled structures quickly during the high-speed machining. We demonstrate some applications, such as thin-walled cylinders and hemispherical shells, to verify the usefulness of this method and compare the analyzed dimensional accuracy of typical parts of the structures.

Lateral buckling of thin-walled members with openings considering shear lag

  • Wang, Quanfeng
    • Structural Engineering and Mechanics
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    • v.5 no.4
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    • pp.369-383
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    • 1997
  • The classical theory of thin-walled members is unable to reflect the shear lag phenomenon since it is based on the assumption of no shearing strains in the middle surface of the walls. In this paper, an energy equation for the lateral buckling of thin-walled members has been derived which includes the effects of torsion, warping and, especially, the shearing strains which reflect the shear lag phenomenon. A numerical analysis for the lateral buckling of thin-walled members with openings by using Galerkin's method of weighted residuals has been presented. The proposed numerical values and the predictions by experiment for the lateral buckling loads are to agree closely in the paper. The results from these comparisons show that the proposed method here is capable of predicting the lateral buckling of thin-walled members with openings. The fast convergence of the results indicates the numerical stability of the method. By the study, a very complex practical eigenvalue problem is transformed into a very simple one of solving only a linear equation with one variable.

Crush Characteristics of Thin-walled Rectangular Tube (박판사각튜브의 압괴 특성)

  • 이종선
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.261-266
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    • 1998
  • In this study, crush characteristics of thin-walled rectangular tube is investigated. The stiffness of the element is obtained from analytical moment-rotation relationship and approximated load-deflection relationship of thin-walled rectangular tube. A computer program is developed for the large deformation analysis of frame. An incremental displacement method is used in the program and at each incremental stage, the stiffness matrix of the total structure is checked with the state each element for bending and compression.

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A Study on Reliability Based Design Optimization For Thin Walled Beam Structures (박판보 구조물의 신뢰성 최적 설계에 관한 연구)

  • Lee, Sun-Byung;Yim, Hong-Jae;Baik, Serl
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.414-419
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    • 2001
  • In this research, reliability based optimum design is presented for the thin walled beam structures. Deterministic and stochastic optimum design are compared for the thin walled beam structures. Monte Carlo simulation is used for stochastic optimum design with consideration of probabilistic distribution of representative section properties of the thin walled beams with the Response Surface Method.

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