Local Stability of Beams with a Flexible Wall with the Concentrated Force Action

2019 ◽  
Vol 974 ◽  
pp. 529-534
Author(s):  
Alexej I. Pritykin ◽  
Ilja E. Kirillov
Keyword(s):  
Local Stability ◽  
Stability Loss ◽  
Analysis Tool ◽  
Loss Of Stability ◽  
The Finite Element Method ◽  
Concentrated Force ◽  
Code Of Practice ◽  
Calculation Results ◽  
Flexible Wall ◽  
The Stability

The article considers the local stability of hinged supported beams with a flexible wall, supported by paired stiffeners on the supports and loaded with a concentrated force in the middle of the span. To prevent the loss of stability of the wall from compression, another edge was installed in the area of ​​application of force. The materials considered as beams were steel, aluminum, and stainless steel. In this work, the beam material is steel C345. The study was conducted by analyzing the requirements of the Code of Practice for beams with a flexible wall in terms of the stability loss caused by the two types of deformations - shear and bending. By means of small simplifications, the requirements of the Code of Practice have been transformed into empirical dependencies convenient for practical calculations for estimating the critical loads on the beam. The finite element method with ANSYS software was used as an effective analysis tool. It has been established that in some cases the cause of loss of stability is a shift, and in others - a bend. A criterion for changing the forms of buckling was also obtained. The calculation results for the obtained dependences are in satisfactory agreement with the FEM and experimental data.

scholarly journals ALGORITHM AND SOFTWARE FOR CALCULATING THE STABILITY OF THE FORM OF EQUILIBRIUM OF DISCRETE SYSTEMS

2019 ◽  
Vol 13 (3) ◽  
pp. 44-49
Author(s):  
A.A. SHKURUPIY ◽  
A.N. PASCHENKO ◽  
P.B. MYTROFANOV
Keyword(s):  
Discrete Systems ◽  
Stability Loss ◽  
Transcendental Equation ◽  
Loss Of Stability ◽  
Displacement Method ◽  
Software Complex ◽  
Complex Functions ◽  
Transcendental Functions ◽  
The Stability ◽  
Theoretical Mechanics

The paper presents an algorithm for calculating the stability of the form of equilibrium of the first kind of compressed discrete systems by the method of displacements in combination with themethods of iterations and bisection. The use of the displacement method in combination with the iteration and bisection methods makes it possible to effectively determine the minimum critical stress or strain at the first bifurcation and their corresponding form of loss of stability, both for statically determined and statically undetectable systems. This approach, using matrixforms, makes it possible to significantly simplify the calculations of the analytical condition for the loss of stability of compressed discrete systems (the stability loss equation), which has high orders, as well as to construct the form of loss of stability corresponding to a critical load, that is, to solve the problem of loss of stability of equilibrium. The calculation of the compressed discrete system on the stability of the form of equilibrium actually reduces to the solution of the difficultly described nonlinear transcendental equation, which is the equation of loss of stability. The difficulty lies in the absence of an analytical solution of such an equation due to the presence of complex functions of Zhukovsky, which have transcendental functions in their structure. Such solution can be performed only with the use of numerical methods. This algorithm for calculating the loss of equilibrium of the first kind of compressed discrete systems by displacement in combination with the methods of iteration and bisection is implemented in the software complex "Persist" for a PC in Windows OS. The program was approbated and implemented in theeducational process at the Department of Structural and Theoretical Mechanics of the Poltava National Technical Yuri Kondratyuk University during the training of specialists in engineering specialties.

scholarly journals STABILITY OF ROTATING CIRCULAR CYLINDRICAL SHELL SUBJECT TO AN AXIAL AND ROTATIONAL FLUID FLOW

2017 ◽  
Vol 18 (9) ◽  
pp. 84-97
Author(s):  
S.A. Bochkarev ◽  
V.P. Matveenko
Keyword(s):  
Finite Element Method ◽  
Fluid Flow ◽  
Boundary Conditions ◽  
Circular Cylindrical Shell ◽  
Loss Of Stability ◽  
Rotating Fluid ◽  
The Finite Element Method ◽  
The Stability ◽  
Rotating Shell ◽  
Simultaneous Rotation

This paper is concerned with the stability analysis of rotating cylindrical shells conveying a co-rotating fluid. The problem is solved by the finite element method for shells subjected to different boundary conditions. It has been found that the loss of stability for a rotating shell under the action of the fluid having both axial and circumferential velocity components depends on the type of boundary conditions imposed on the shell ends. The results of numerical calculations have shown that for different variants of boundary conditions a simultaneous rotation of shell and the fluid causes an increase or decrease in the critical velocity of axial fluid flow.

The Alculation Method of Stable Bearing Capacity of Portal Frame

2013 ◽  
Vol 351-352 ◽  
pp. 329-336 ◽  
Author(s):  
Xu Chen ◽  
Hui Min Li
Keyword(s):  
Exact Solution ◽  
Bearing Capacity ◽  
Carrying Capacity ◽  
Lateral Displacement ◽  
Reference Value ◽  
Frame Structure ◽  
Concentrated Force ◽  
Portal Frame ◽  
Calculation Results ◽  
The Stability

In recent years, the portal frame structure in the actual project has been widely used, but using the finite element method calculation of stable bearing capacity of portal frame is more complex, and very difficult to the design and construction personnel. With the known stability of the cantilever column carrying capacity and the vertex of the lateral displacement under concentrated force, the establishment of the ratio of the portal frame stability capacity and the stability of the cantilever column carrying capacity both in the same concentrated force vertex lateral displacement than the relationship between the structural mechanics solver to seek out frame to the lateral displacement of the vertex under concentrated force, obtained by computing the stability capacity of the portal frame, and with the exact solution comparison and found that the methods of theoretical calculation results coincide with the exact solution, and then get an easy way of solving the portal frame stable bearing capacity. After numerical example, this method is simple, easy to master, and it has important reference value.

scholarly journals Scheme of soil stability losses in the laboratory tray

2020 ◽  
Vol 212 ◽  
pp. 02009
Author(s):  
Alexander Kremnev ◽  
Nikolay Vishnyakov ◽  
Victoria Ermachenko
Keyword(s):  
Stability Loss ◽  
Soil Stability ◽  
Loss Of Stability ◽  
Sliding Surface ◽  
Combined Action ◽  
Soil Foundation ◽  
The Stability ◽  
Question Today

The object of the research is the diagram of the stability loss of the soil foundation. Currently, there are still discussions about how the stability of the subgrade undergoes the combined action of vertical and horizontal loads. Most often, in the calculation, the sliding surface is taken to be circular. Whether this is true, especially for a heterogeneous or anisotropic base, is an important question today. In the work, chute tests were carried out, with modeling of the scheme of loss of stability of anisotropic and isotropic bases and results were obtained that confirm the formation of a circular cylindrical sliding surface.

Researches of stability of monolithic and layered plates under compression

2021 ◽  
Vol 11 ◽  
pp. 69-84
Author(s):  
E. I. Oreshko ◽  
◽  
V. S. Erasov ◽  
O. A. Lashov ◽  
N. O. Yakovlev ◽  
...  
Keyword(s):  
High Strength ◽  
Composite Panel ◽  
Loss Of Stability ◽  
The Finite Element Method ◽  
Layered Plates ◽  
Euler Formula ◽  
Local Loss ◽  
Aluminum Lithium ◽  
The Stability ◽  
Experimental Values

The results of calculations of the stability of monolithic and layered plates, obtained by analytical and numerical methods, are presented, which are compared with experimental data. The obtained results of stability calculations are within the limits of the permissible error. The results of numerical calculations of stability by the finite element method in the ANSYS program turned out to be higher than the values ​​determined by the Euler formula and lower than the results obtained by the formula for calculating the stability of plates. To study the bearing capacity of layered samples under compression, an assessment of their stability was carried out with different numbers and arrangement of layers of alloy and composite material. The optimal layouts of layers in the material for designing a composite panel have been determined. The results were used to design a composite wing panel based on sheets and profiles made of high-strength aluminum-lithium alloy and laminated aluminum-fiberglass. Stability of the composite panel under compression were 7% higher than the experimental values due to the local loss of stability of its elements, which precedes the general loss of stability and reduces the value of the critical load.

scholarly journals Tall von-Mises trusses' skew-symmetric deformation

2020 ◽  
pp. 114-126
Author(s):  
Serhii Bilyk ◽  
Hennadii Tonkacheiev ◽  
Artem Bilyk ◽  
Vitalii Tonkacheiev
Keyword(s):  
Vertical Axis ◽  
Stability Loss ◽  
Structure Design ◽  
Concentrated Force ◽  
Wide Range ◽  
Symmetric Deformation ◽  
Inclination Angles ◽  
The Stability ◽  
The Individual ◽  
Von Mises

The work’s aim is to investigate the tall two-rods three-hinged von-Mises trusses' deformation regularities at the sloped load that applied to the ridge joint.The horizontal elastic support influence in the ridge joint when changing the force's inclination angle in a wide range is also investigated Particular attention is paid to the tall two-rod trusses' skew-symmetric stability loss possibility. The possibility of the skew-symmetric shape of а loss of stability of high trusses with at a very small angle of inclination of the force from the vertical axis was confirmed. The horizontal elastic support's influence on increasing the stability against skew-symmetric deformation was shown.It was found that skew-symmetry deformation is essentially non-linear, but under certain conditions it is not catastrophic.It is also noticed that asymmetric deformation depends on vertical deformation.Scientific novelty lies in a detailed study of the tall two-rod three-hinged trusses' deformation, and the establishment of the tendency of such structures to skew-symmetric buckling.The tall von-Mises trusses' new detailed deformation regularities character at skew-symmetric deformation at small inclination angles of force that applied in the ridge joint has been established. Also, the two-rod structures' new deformation regularities has been revealed with a wide inclination angles range of the concentrated force applied in the ridge joint. It is shown that on increasing the loading's inclination angles, which coincide with the rod's inclination angles, the stability loss of the individual rods is possible, since there is a significant increase in the truss' carrying capacity. The research results can be used in the structure design of large general dimensions, modeling of which gives the real structure work under various loads.

scholarly journals Some aspects of consideration of initial imperfections in the calculations of stability of thin-walled elements of open profile

2021 ◽  
pp. 122-128
Author(s):  
Ivan Okhten ◽  
Olha Lukianchenko
Keyword(s):  
Middle Surface ◽  
Stability Loss ◽  
Critical Force ◽  
The Finite Element Method ◽  
Geometric Imperfections ◽  
Initial Imperfections ◽  
General Stability ◽  
Initial Geometric Imperfections ◽  
Linear And Nonlinear ◽  
The Stability

Performed analysis of the initial geometric imperfections influence on the stability of the open C-shaped bars. Test tasks were solved in MSC Nastran, which is based on the finite element method. Imperfections are given in different formulations: the general stability loss of an ideal bar, of wavy bulging of walls and shelves, of deplanation of a bar. To model imperfections, has been developed a program which for the formation of new coordinates of the nodes of the "deformed" model, the components of a vector similar to the form of stability loss are added to the corresponding coordinates of the middle surface of the bar. In this way, you can set initial imperfections in the forms of stability loss of the bar with different amplitude. Researches made with different values of the imperfection amplitude and eccentricity of applied efforts. All tasks are performed in linear and nonlinear staging. The conclusion is made regarding the influence of initial imperfections form and imperfection amplitude on the critical force in nonlinear calculations. It was found that the most affected are imperfections, which are given in the form of total loss of stability. It was revealed the influence of the imperfection amplitude on the magnitude of the critical force for such imperfections. The influence of imperfections amplitude given in the form of wavy bulging walls and in the form of deplanations is not affected on the value of the critical force.

Slope Stability Analysis under the Condition of Seepage

2012 ◽  
Vol 204-208 ◽  
pp. 241-245
Author(s):  
Yang Jin
Keyword(s):  
Finite Element Method ◽  
Shear Strength ◽  
Slope Stability ◽  
Negative Impact ◽  
Strength Reduction ◽  
Soil Slope ◽  
Failure State ◽  
Calculation Results ◽  
The Stability ◽  
Shear Strength Reduction

The stability of soil slope under seepage is calculated and analyzed by using finite element method based on the technique of shear strength reduction. When the condition of seepage or not is considered respectively, the critical failure state of slopes and corresponding safety coefficients can be determined by the numerical analysis and calculation. Besides, through analyzing and comparing the calculation results, it shows that seepage has a negative impact on slope stability.

scholarly journals Determination of Transverse Shear Stiffness of Sandwich Panels with a Corrugated Core by Numerical Homogenization

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1976
Author(s):  
Tomasz Garbowski ◽  
Tomasz Gajewski
Keyword(s):  
Transverse Shear ◽  
Shear Stiffness ◽  
The Finite Element Method ◽  
Homogenization Procedure ◽  
Plate Structures ◽  
Corrugated Board ◽  
Energy Equivalence ◽  
The Stability ◽  
Global Stiffness Matrix

Knowing the material properties of individual layers of the corrugated plate structures and the geometry of its cross-section, the effective material parameters of the equivalent plate can be calculated. This can be problematic, especially if the transverse shear stiffness is also necessary for the correct description of the equivalent plate performance. In this work, the method proposed by Biancolini is extended to include the possibility of determining, apart from the tensile and flexural stiffnesses, also the transverse shear stiffness of the homogenized corrugated board. The method is based on the strain energy equivalence between the full numerical 3D model of the corrugated board and its Reissner-Mindlin flat plate representation. Shell finite elements were used in this study to accurately reflect the geometry of the corrugated board. In the method presented here, the finite element method is only used to compose the initial global stiffness matrix, which is then condensed and directly used in the homogenization procedure. The stability of the proposed method was tested for different variants of the selected representative volume elements. The obtained results are consistent with other technique already presented in the literature.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

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