Buckling Analysis of the Tube Compression-Bending Member in Elastic-Plastic State with ANSYS

2011 ◽  
Vol 327 ◽  
pp. 143-148
Author(s):  
Zhi Cai Jiang ◽  
Wei Lian Qu
Keyword(s):  
Axial Compression ◽  
Bending Moment ◽  
Steel Structure ◽  
Plastic Instability ◽  
Plastic State ◽  
Axial Pressure ◽  
Nonlinear Buckling ◽  
Elastic Plastic ◽  
Compression Stiffness ◽  
The Relationship

Stability is an important issue in steel structure design.When the steel member is subjected to elastic-plastic instability, the axial compression stiffness reduces with the increasing axial pressure and bending moment at end. Therefore, the authors analyze the process of steel member that is instable in elastic-plastic state in this paper by studying the degradation laws of axial compression stiffness. The eigenvalue buckling and nonlinear buckling analyses of axially compressed member and compression-bending member are carried out by using commercial package ANSYS in this study. The relationship curve between the axial force at end and the axial compression stiffness and the relationship surface among the axial pressure at end, bending moment at end and the axial compression stiffness are determined respectively. The made observations indicate that it is feasible to analyze the process of the steel member that is instable in elastic-plastic state by investigating the degradation properties of axial compression stiffness, which becomes lower with axial pressure at end and bending moment at end.

Application of the Cyclic Strain Approach to the Fatigue Failure of Ship Structural Details

1987 ◽  
Vol 31 (03) ◽  
pp. 177-185
Author(s):  
Wolfgang Fricke ◽  
Hans Paetzold
Keyword(s):  
Fatigue Life ◽  
Plastic Region ◽  
Steel Structure ◽  
Cyclic Strain ◽  
Cyclic Stress ◽  
Damage Parameter ◽  
Elastic Plastic ◽  
Strain Behavior ◽  
Structural Details ◽  
The Relationship

The cyclic strain approach is useful for determining the fatigue life of notches strained in the elastic-plastic region. Examples are the flame-cut edges of cutouts in the ship steel structure. After the description of the cyclic stress-strain behavior of the usual mild steel, the individual elements of the approach are described: the probability distribution of load amplitudes, the relationship between load and local elastic-plastic strain, the relationship between the damage parameter and fatigue life, and finally the damage accumulation law. The approach is illustrated by two examples of longitudinal/transverse web intersections. In the first, the predicted life is confirmed by experimental results. The second example shows the approach for complicated load combinations. It is hoped that this paper will contribute to sound and crack-free ship structural details, particularly if unusual loads are applied to well-tried details or if simplified designs are introduced.

scholarly journals PLASTIC DEFORMATIONS OF STEEL FRAME: STATICS AND DYNAMICS

2010 ◽  
Vol 2 (3) ◽  
pp. 101-105 ◽  
Author(s):  
Vytautas Kargaudas ◽  
Nerijus Adamukaitis
Keyword(s):  
Dynamic Analysis ◽  
Cross Section ◽  
Axial Force ◽  
Bending Moment ◽  
Transverse Force ◽  
Steel Frame ◽  
Plastic State ◽  
Strain Diagram ◽  
Plastic Deformations ◽  
Elastic Plastic

When all deformations of a column are elastic, transverse deflections of the column depend on transverse force and axial displacements depend on axial force only. These classical dependences are unsuitable for elastic-plastic deformations. Plastic deformations develop in columns when steel frame is influenced by extreme action. When a steel column is in the elastic-plastic state, the distribution of elastic and plastic deformations in the cross-section depends on both the bending moment and compressing force. The ideal elastic-plastic material is assumed in this investigation (Prandtl stress – strain diagram). If the shape of the column section is double tee, flange width is neglected with respect to web height, but the area of the flange cross-section is assumed a constant. Single-sided or double-sided yield depends on the moment and force, and therefore curvature and the axial strain of the column can be calculated when yielding dependences are determined. Transverse and axial displacements of the highest point of the column are deduced by integration and depend on two arguments: bending force and axial force. These dependences are essentially non-linear, so linear approximations can be assessed for some vicinity of axial force and bending moment values. When axial force is a constant and transverse force increases, both axial and transverse displacements tend to increase. If transverse force is a constant and axial force increases, both displacements increases but dependence lines remain different and depend on cross-section shape parameter equal to the ratio of the flange area and the area of the whole cross-section. A distinguished feature of plastic deformations is dependence on the history of loading a frame of which can be selected in an arbitrary way by an investigator if a quasi-static solution is under examination. The loading of a frame and inertia forces have to be deduced if dynamic analysis is studied. Not only the ultimate result but also the way of approaching a plastic piston – plastic hinge is important. The bended and compressed column is the structure when inelastic dynamic analysis is really important.

A Method for Calculating the Amount of the Deflection and Force-Energy Parameters for Copper-Clad Steel Tube in the Process of Straightening

2013 ◽  
Vol 477-478 ◽  
pp. 137-140
Author(s):  
Liang Yu Xia ◽  
Dong Ming Sun ◽  
Gui Rong Kang ◽  
Jian Sun
Keyword(s):  
Mathematical Model ◽  
Engineering Application ◽  
Bending Moment ◽  
Scientific Basis ◽  
Steel Tube ◽  
Elastic Plastic ◽  
Energy Parameters ◽  
Continuous Bending ◽  
Clad Steel ◽  
The Relationship

Based on Roller Straightening Theory and Elastic-Plastic Beam Research, A Appropriate Mathematical Model of Straightening has Set up.The Author Regards the Tube as a Continuous Bending Beam and Discuss in Detail the Relationship between the Straightening Force and the Bending Moment. Calculating the Amount of Deflection for Tube. in this way ,it Provided a Scientific Basis for the Copper-Clad Steel Tube Straightening Parameter Set and Engineering Application.

scholarly journals The Relationship Between Moment and Curvature and the Elastic-Plastic Seismic Response Analysis of High Pier Section

2015 ◽  
Vol 9 (1) ◽  
pp. 892-899 ◽  
Author(s):  
Jinxue Jun ◽  
Wanggen Hui
Keyword(s):  
Seismic Analysis ◽  
Time History ◽  
Bending Moment ◽  
Moment Of Inertia ◽  
Response Analysis ◽  
Thin Wall ◽  
Elastic Plastic ◽  
Section Size ◽  
The Moment ◽  
The Relationship

Nonlinear hysteresis characteristics are usually utilized in the elastic-plastic seismic analysis of the structure of bridge. These characteristics may be described by the relationship of section bending moment and curvature. This relationship can be obtained by the section size and reinforcement, which is also a simple and time-saving method to evaluate the seismic behavior of the section. The research is conducted on the effect of section bending moment and curvature. Then, five different sections are chosen to observe their effects on bending moment and curvature. The results indicate that with the increase in section size, the crack, the yield, the moment damage and the curvature of the section also increase. The increase in section size refers to the increase in moment of inertia, so with the increase in the moment of inertia, the resistance to crack, field and damage of the bridge pier become stronger. On this basis, the elastic-plastic time history analysis of Wu Guan super highway Gan Gou Zi Bridge is carried out. It shows that the capacity of energy dissipation by hysteretic of the Rectangular thin-wall pier is better than the twin shaft pier. So it is best to use rectangular thin-wall pier in the same condition.

Nonlinear Buckling Behaviour of Imperfect Cylindrical Shells under Global Bending in the Elastic-Plastic Range

2012 ◽  
Vol 204-208 ◽  
pp. 1045-1052
Author(s):  
Lei Chen ◽  
Yi Liang Peng ◽  
Li Wan
Keyword(s):  
Cylindrical Shells ◽  
Plastic State ◽  
Plastic Range ◽  
Nonlinear Buckling ◽  
Buckling Strength ◽  
Elastic Plastic ◽  
Capacity Curves ◽  
Shell Buckling ◽  
Buckling Behavior ◽  
Structural Applications

Many thin cylindrical shells are used in structural applications in which the dominant loading condition is global bending. Key examples include chimneys, tubular piles, wind generation towers and tall silos. Their thickness lies in a tricky range which is extremely thin for the structural tube community and very thick for the shell buckling community. The buckling strength of these structures is dominated by extensive plasticity, but the fully plastic state is usually far from being attained. This paper explores the buckling strength of imperfect thin cylindrical shells under global bending in the elastic-plastic range. The capacity curves of the new Eurocode EN 1993-1-6 (2007) are used to match the final results. The results show that the capacity curves can capture this buckling behavior accurately and safely for different types of material models. It is assumed that the shell is held circular by rings or boundaries at reasonable intervals, effectively restraining ovalisation. It is hoped that these results will make a useful contribution towards resolving the misunderstandings and controversy that has been evident in this field in recent years.

Elasto-plastic state of curve beam system subjected to complex loading

1996 ◽  
Vol 18 (4) ◽  
pp. 14-22
Author(s):  
Vu Khac Bay
Keyword(s):  
Cylindrical Shell ◽  
Solution Method ◽  
Complex Loading ◽  
Numerical Results ◽  
Elastic Solution ◽  
Plastic State ◽  
Curve Beam ◽  
Elastic State ◽  
Elastic Plastic ◽  
Beam System

Investigation of the elastic state of curve beam system had been considered in [3]. In this paper the elastic-plastic state of curve beam system in the form of cylindrical shell is analyzed by the elastic solution method. Numerical results of the problem and conclusion are given.

scholarly journals The effect of flexural–torsional buckling on the stability of timber members: a case study

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Osama A. B. Hassan
Keyword(s):  
Axial Compression ◽  
Bending Moment ◽  
List Type ◽  
Torsional Buckling ◽  
Solution Methods ◽  
Simplified Solution ◽  
The Stability ◽  
Flexural Torsional Buckling ◽  
Building Engineering

Abstract This study investigates the stability of timber members subjected to simultaneously acting axial compression and bending moment, with possible risk for torsional and flexural–torsional buckling. This situation can occur in laterally supported members where one side of the member is braced but the other side is unbraced. In this case, the free side will buckle out of plane while the braced side will be prevented from torsional and flexural–torsional buckling. This problem can be evident for long members in timber-frame structures, which are subjected to high axial compression combined with bending moments in which the member is not sufficiently braced at both sides. This study is based on the design requirement stated in Eurocode 5. Solution methods discussed in this paper can be of interest within the framework of structural and building Engineering practices and education in which the stability of structural elements is investigated. Article Highlights This case study investigates some design situations where the timber member is not sufficiently braced. In this case, a stability problem associated with combined torsional buckling and flexural buckling can arise. The study shows that the torsional and/or flexural–torsional buckling of timber members can be important to control in order to fulfil the criteria of the stability of the member according to Eurocode 5 and help the structural engineer to achieve safer designs. The study investigates also a simplified solution to check the effect of flexural torsional buckling of laterally braced timber members.

Transverse Young's Moduli and Cell Shapes in Coniferous Early Wood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ugai Watanabe ◽  
Minoru Fujita ◽  
Misato Norimoto
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Bending Moment ◽  
Cell Models ◽  
Young’S Moduli ◽  
Cell Shapes ◽  
The Difference ◽  
Square Cells ◽  
Experimental Values ◽  
The Relationship

Summary The relationship between transverse Young's moduli and cell shapes in coniferous early wood was investigated using cell models constructed by two dimensional power spectrum analysis. The calculated values of tangential Young's modulus qualitatively explained the relationship between experimental values and density as well as the difference in experimental values among species. The calculated values of radial Young's modulus for the species having hexagonal cells agreed well with the experimental values, whereas, for the species having square cells, the calculated values were much larger than the experimental values. This result was ascribed to the fact that the bending moment on the radial cell wall of square cell models was calculated to be small. It is suggested that the asymmetrical shape of real wood cells or the behavior of nodes during ell deformation is an important factor in the mechanism of linear elastic deformation of wood cells.

Elastic-Plastic Analysis of an Elbow With Axial Part-Through Internal Crack at Crown Under In-Plane Bending

2008 ◽  
Author(s):  
K. M. Prabhakaran ◽  
S. R. Bhate ◽  
V. Bhasin ◽  
A. K. Ghosh
Keyword(s):  
Finite Element ◽  
Crack Depth ◽  
Bending Moment ◽  
Internal Crack ◽  
J Integral ◽  
Finite Element Analyses ◽  
Integrity Assessment ◽  
Elastic Plastic ◽  
Axial Part ◽  
Plane Bending

Piping elbows under bending moment are vulnerable to cracking at crown. The structural integrity assessment requires evaluation of J-integral. The J-integral values for elbows with axial part-through internal crack at crown under in-plane bending moment are limited in open literature. This paper presents the J-integral results of a thick and thin, 90-degree, long radius elbow subjected to in-plane opening bending moment based on number of finite element analyses covering different crack configurations. The non-linear elastic-plastic finite element analyses were performed using WARP3D software. Both geometrical and material nonlinearity were considered in the study. The geometry considered were for Rm/t = 5, and 12 with ratio of crack depth to wall thickness, a/t = 0.15, 0.25, 0.5 and 0.75 and ratio of crack length to crack depth, 2c/a = 6, 8, 10 and 12.

Elastic-plastic bending of the pipeline under combined loading

2021 ◽  
pp. 372-377
Author(s):  
Виктор Миронович Варшицкий ◽  
Евгений Павлович Студёнов ◽  
Олег Александрович Козырев ◽  
Эльдар Намикович Фигаров
Keyword(s):  
Internal Pressure ◽  
Limit State ◽  
Bending Moment ◽  
Axial Direction ◽  
Longitudinal Force ◽  
Combined Loading ◽  
Dimensional Problem ◽  
Elastic Plastic ◽  
Pipeline Section ◽  
Thin Walled Pipe

Рассмотрена задача упругопластического деформирования тонкостенной трубы при комбинированном нагружении изгибающим моментом, осевой силой и внутренним давлением. Решение задачи осуществлено по разработанной методике с помощью математического пакета Matcad численным методом, основанным на деформационной теории пластичности и безмоментной теории оболочек. Для упрощения решения предложено сведение двумерной задачи к одномерной задаче о деформировании балки, материал которой имеет различные диаграммы деформирования при сжатии и растяжении в осевом направлении. Проведено сравнение с результатами численного решения двумерной задачи методом конечных элементов в упругопластической постановке. Результаты расчета по инженерной методике совпадают с точным решением с точностью, необходимой для практического применения. Полученные результаты упругопластического решения для изгибающего момента в сечении трубопровода при комбинированном нагружении позволяют уточнить известное критериальное соотношение прочности сечения трубопровода с кольцевым дефектом в сторону снижения перебраковки. Применение разработанной методики позволяет ранжировать участки трубопровода с непроектным изгибом по степени близости к предельному состоянию при комбинированном нагружении изгибающим моментом, продольным усилием и внутренним давлением. The problem of elastic plastic deformation of a thin-walled pipe under co-binned loading by bending moment, axial force and internal pressure is considered. The problem is solved by the developed method using the Matcad mathematical package by a numerical method based on the deformation theory of plasticity and the momentless theory of shells. To simplify the solution of the problem, it is proposed to reduce a twodimensional problem to a one-dimensional problem about beam deformation, the material of which has different deformation diagrams under compression and tension in the axial direction. Comparison with the results of numerical solution of the two-dimensional problem with the finite element method in the elastic plastic formulation is carried out. The obtained results of the elastic-plastic solution for the bending moment in the pipeline section under combined loading make it possible to clarify criterion ratio of the strength of the pipeline section with an annular defect in the direction of reducing the rejection. Application of the developed approach allows to rank pipeline sections with non-design bending in the steppe close to the limit state under combined loading of the pipeline with bending moment, longitudinal force and internal pressure.

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