• Title, Summary, Keyword: Buckling

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Post-buckling analysis of aorta artery under axial compression loads

  • Akbas, Seref Doguscan;Mercan, Kadir;Civalek, Omer
    • Advances in nano research
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    • v.8 no.3
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    • pp.255-264
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    • 2020
  • Buckling and post-buckling cases are often occurred in aorta artery because it affected by higher pressure. Also, its stability has a vital importance to humans and animals. The loss of stability in arteries may lead to arterial tortuosity and kinking. In this paper, post-buckling analysis of aorta artery is investigated under axial compression loads on the basis of Euler-Bernoulli beam theory by using finite element method. It is known that post-buckling problems are geometrically nonlinear problems. In the geometrically nonlinear model, the Von Karman nonlinear kinematic relationship is employed. Two types of support conditions for the aorta artery are considered. The considered non-linear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The aorta artery is modeled as a cylindrical tube with different average diameters. In the numerical results, the effects of the geometry parameters of aorta artery on the post-buckling case are investigated in detail. Nonlinear deflections and critical buckling loads are obtained and discussed on the post-buckling case.

Buckling Length Analysis for Compression Chord in Cold-Formed Steel Cantilever Truss

  • Konkong, Nirut;Aramraks, Trakool;Phuvoravan, Kitjapat
    • International journal of steel structures
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    • v.17 no.2
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    • pp.775-787
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    • 2017
  • The lateral buckling of a cold-formed steel truss structure was investigated. Both an experimental test and finite element analysis presented a good correlation in the failure mechanism of specimens. The critical buckling load of the compression truss chord was analyzed using a South well plot and the analytical method. The transfer matrix method and the governing equation of an Euler column were used to analyze the critical buckling load of a multi-step, uniform chord member with lateral spring supports. Expressions for the buckling length factor presented according to AISI (2012) and the EN 1993-1-3 (2006) specification were compared by experimental testing and the analytical method. The buckling length factor of the experimental test and the analytical model confirmed that the buckling length of a compressed truss chord was less than the distance between the lateral bracing.

A Study on the Buckling Characteristics of Spacer Grids in Pressurized Water Reactor Fuel Assembly (경수로용 핵연료집합체 지지격자의 좌굴특성에 관한 연구)

  • Jeon Sang-Youn;Lee Young-Shin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.4
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    • pp.405-416
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    • 2005
  • This study contains the static buckling tests and static buckling analyses for small size grids and full size grids. The buckling tests and finite element analyses were performed to evaluate the buckling characteristics of the spacer grids in a pressurized water reactor fuel assembly and to evaluate the possibility of the prediction lot the buckling strength of spacer grids. The buckling tests were performed for small size grids and full size grids, and the correlations between buckling strength and the number of straps and the correlations between buckling strength and the number of rows are derived based on the test results. The static buckling analyses were performed to identify the effect of the number of rows and the number of columns on the buckling strength of spacer grid by a finite element method using ANSYS program and the results were compared with the buckling test results.

Buckling of axially compressed composite cylinders with geometric imperfections

  • Taheri-Behrooz, Fathollah;Omidi, Milad
    • Steel and Composite Structures
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    • v.29 no.4
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    • pp.557-567
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    • 2018
  • Cylindrical shell structures buckle at service loads which are much lower than their associated theoretical buckling loads. The main source of this discrepancy is the presence of various imperfections which are created on the cylinder body during different processes as manufacturing, handling, assembling and machining. Many cylindrical shell structures are still designed against buckling based on the experimental data introduced by NASA SP-8007 as conservative lower bound curves. This study employed the numerical based Linear Buckling mode shape Imperfection (LBMI) method and modified it using a stochastic method to assess the effect of geometrical imperfections in more details on the buckling of cylindrical shells with and without the cutout. The comparison of results with those obtained from the numerical Simcple Perturbation Load Imperfection (SPLI) method for cylinders with and without cutout revealed a good correlation. The effect of two parameters of size and number of cutouts on the buckling load was investigated using the linear buckling and Modified LBMI methods. Results confirmed that in cylinders with a small cutout inserting geometrical imperfection using either SPLI or modified LBMI methods significantly reduced the value of the predicted buckling load. However, in cylinders with larger cutouts, the effect of the cutout is dominant, thus considering geometrical imperfection had a minor effect on the buckling loads predicted by both SPLI and modified LBMI methods. Furthermore, the modified LBMI method was employed to evaluate the combination effect of cutout numbers and size on the buckling load. It is shown that in small cutouts, an increasing in the cutout size up to a certain value resulted in a remarkable reduction of the buckling load, and beyond that limit, the buckling loads were constant against D/R ratios. In addition, the cutout number shows a more significant effect on decreasing the buckling load at small D/R ratios than large D/R ratios.

An Investigation of the Shear Buckling Characteristics of Sinusoidal Corrugated Steel Plates (정현파형 주름강판의 전단좌굴특성 분석)

  • Shon, Su-Deok;Yoo, Mi-Na;Lee, Seung-Jae;Kang, Joo-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.3
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    • pp.10-19
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    • 2014
  • Corrugated steel plates are made by fabricating thin steel plates to have trapezoidal or sinusoidal corrugation, and the corrugated plates are able to maintain high out-of-plane rigidity even when they are used instead of thick flat plates. Also, corrugated steel plates have almost no axial rigidity due to the accordion effect. Thus, if they are applied to the webs of plate girders, designing can be easily conducted so that the webs bear only shear stresses. However, unlike flat plates, the shear buckling of corrugated steel plates has very complex characteristics where buckling occurs due to the interaction of local and global buckling, besides local buckling and global buckling. For the investigation of the cause and characteristics of this interactive buckling, studies on sinusoidal corrugated steel plates are fewer than studies on trapezoidal corrugated steel plates. Therefore, in this study, the shear buckling characteristics of sinusoidal corrugated steel plates and the occurrence pattern of interactive buckling were investigated. For the calculation of shear buckling strength, a finite element program was used, and the analysis results were compared with the exact solution. In addition, the characteristics of buckling stress change and the change of buckling mode shape depending on corrugation thickness and shape parameter were analyzed, and by comparing these results with the results of a theoretical equation, the timing of buckling mode change was analyzed.

Study on Buckling Instability of Expansion Tube using Finite Element Method (유한요소법을 이용한 팽창튜브의 좌굴불안전성에 관한 연구)

  • Choi, Won-Mok;Kwon, Tae-Su;Jung, Hyun-Sung
    • Journal of the Korean Society for Railway
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    • v.13 no.2
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    • pp.147-151
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    • 2010
  • Since the kinetic energy is dissipated through plastic deformation energy generated in expanding process of the tube by a die. In order to successfully absorb the kinetic energy there should be no buckling in the expansion tube during expanding process. The buckling instability of the expansion tubes is affected by the initial boundary conditions, tube thickness and length. In this study, the effects of the tube thickness except length and initial boundary condition on the buckling instability are studied using a finite element method. In addition, Analysis procedure for nonlinear post-buckling analysis of expansion tube is established. There are three kinds of finite element analysis procedures for buckling analysis of expansion tube, quasi-static analysis, linear buckling analysis and nonlinear post-buckling analysis. The effect of the geometry imperfections defined as linear superimposition of buckling modes is considered in the nonlinear post-buckling analysis. The results of finite element analysis indicate that the buckling load increase with increase of thickness of tube and geometry imperfection. Finial buckling shapes are changed with respect to the geometry imperfection.

Research Advances on Tension Buckling Behaviour of Aerospace Structures: A Review

  • Datta, Prosun Kumar;Biswas, Sauvik
    • International Journal of Aeronautical and Space Sciences
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    • v.12 no.1
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    • pp.1-15
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    • 2011
  • This paper reviews most of the research done in the field of tensile buckling characteristics pertaining to aerospace structural elements with special attention to local buckling and parametric excitation due to periodic loading on plate and shell elements. The concepts of buckling in aerospace structures appear as the result of the application of a global compressive applied load or shear load. A less usual situation is the case, in which a global tensile stress creates buckling instability and the formation of complex spatial buckling pattern. In contrast to the case of a pure compression or shear load, here the applied macroscopic load has no compressive component and is thus globally stabilizing. The instability stems from a local compressive stress induced by the presence of a defect, such as a crack or a hole, due to partial or non-uniform applied load at the far end. This is referred to as tensile buckling. This paper discusses all aspects of tensile buckling, theoretical and experimental. Its far reaching applications causing local instability in aerospace structural components are discussed. The important effects on dynamic stability behaviour under locally induced periodic compression have been identified and influences of various parameters are discussed. Experimental results on simple and combination resonance characteristics on plate structures due to tensile buckling effects are elaborated.

A Study on the Buckling in Fillet Welds of Sheets (박판 필릿용접구조물의 좌굴변형에 관한 연구)

  • Chu, Hwan-Su;Cho, Sang-Myung
    • Journal of Welding and Joining
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    • v.27 no.3
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    • pp.60-66
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    • 2009
  • The structures distorted by welding have to be corrected. Since the correcting work needs a lot of costs and time, it is very important to minimize the buckling distortion due to welding of thin plate structure. Therefore the aim of this study is to investigate the effect of single bead on plate welding and fillet welding on the buckling distortion. In the single bead on plate welding, it was found that the welding speed and welding sequence were the most dominant factors on distortion. In the fillet welding, there were four typical buckling modes observed, and the welding sequence was the most influential factor on the buckling distortion. However typical distortion measuring method is not considered for the distortion correcting process costs of each buckling modes, therefore, in this study, the measuring method is developed to classify the buckling modes for torsion of specimen and buckling distortion depend on nodal point for the bead on plate welding specimen and fillet welds.

The study on the buckling instability of tube type crash energy absorber (튜브형 충돌에너지흡수부재의 좌굴불안전성에 대한 연구)

  • Choi, Won-Mok;Jung, Hyun-Sung;Kwon, Tae-Su
    • Proceedings of the KSR Conference
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    • pp.1564-1570
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    • 2007
  • There are normally two types of the energy absorbers used in the crashworthiness of trains. The first is a structure type, which mainly used in not only the primary structures of the train but also the crash energy absorbers at the accident. The second is a module type, which just absorbs the crash energy independent of the primary structures and attached to the structures of the train. The expansion and inversion tube are widely used as the module type crash energy absorbers, especially in the train. The tubes should not be buckled under the load acting on the end of the tube in longitudinal direction during absorbing the crash energy. The buckling stability of the tubes is affected by the boundary conditions, thickness and length of tube. In this study, the effects of the length and thickness of the tubes on the buckling load are studied by using the ABAQUS, a commercial finite element analysis program, and then presents the guideline to design the tube. The analysis processes to compute the buckling load consist of a linear buckling analysis and a nonlinear post-buckling analysis. The buckling modes are evaluated by the linear buckling analysis, as using these modes, the buckling loads are computed by the nonlinear post-buckling analysis.

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Use of Buckling Coefficient in Predicting Buckling Load of Plates with and without Holes (홀의 유무에 따른 평판 좌굴하중 산정을 위한 좌굴계수)

  • Behzad, Mohamazadeh;Noh, Hyuk-Chun
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.5 no.3
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    • pp.1-7
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    • 2014
  • Buckling, a form of failure happened to plated structures, is investigated in this study. The main focus is to investigate the effects of thickness of the plates having through-thickness holes on buckling when the plate is subjected to in-plane compression. Plates having length of 200mm and width of 100mm are chosen to have thickness in range from 0.50mm to 10mm. Two holes of diameters of 20mm are implemented in plates. The finite element procedure using ABAQUS is applied for analyses. Then using the Gerard and Becker equation compressive buckling coefficients, Kc, are calculated and presented to enable engineers to calculate buckling load for the desired plate with holes in specific dimension. In order to generalize the obtained results, verification analysis has been performed by taking plates having different dimensions from the original ones used in this study. The verification showed the capability of buckling coefficients to predict buckling stresses of plates in various dimensions.