scholarly journals Stability Analysis of Symmetrical Rotor-Bearing Systems With Internal Damping Using Finite Element Method

1996 ◽  
Author(s):  
L. Forrai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Complex Form ◽  
Internal Damping ◽  
Bending Vibrations ◽  
Rotor Bearing ◽  
The Matrix ◽  
The Stability ◽  
Element Method

This paper deals with the stability analysis of self-excited bending vibrations of linear symmetrical rotor-bearing systems caused by internal damping using the finite element method. The rotor system consists of uniform circular Rayleigh shafts with internal viscous damping, symmetrical rigid disks, and discrete undamped isotropic bearings. By combining the sensitivity method and the matrix representation of the rotor dynamic equations in complex form to assess stability, it is proved theoretically that the stability threshold speed and the corresponding whirling speed coincide with the first forward critical speed regardless of the magnitude of the internal damping.

RESEARCH OF THE STABILITY ANALYSIS FOR FRAME BUILDINGS USING FINITE ELEMENT METHOD

2019 ◽  
Vol 7 (1) ◽  
pp. 45-48
Author(s):  
Галина Кравченко ◽  
Galina Kravchenko ◽  
Елена Труфанова ◽  
Elena Trufanova ◽  
Анастасия Бойко ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Design Method ◽  
Progressive Collapse ◽  
Structural Member ◽  
Mode Shapes ◽  
Frame Buildings ◽  
The Stability ◽  
Element Method

In this article, general stability analysis is considered, in order to obtain the load-bearing capacity of the multy-storey building using finite element method. There are some graphical interpretations for FE results that illustrate safety factor for each structural member of the structure and different mode shapes with their corresponding frequencies. These results can be used to improve the structural member design method in case of progressive collapse possibility. The article provides recommendations for strengthening and design of structural member.

A decoupled finite element method with diferent time steps for the nonstationary Darcy–Brinkman problem

2020 ◽  
Vol 28 (1) ◽  
pp. 33-62 ◽  
Author(s):  
Cheng Liao ◽  
Pengzhan Huang ◽  
Yinnian He
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Error Estimates ◽  
Computational Time ◽  
Coupled Method ◽  
Numerical Tests ◽  
The Stability ◽  
Element Method

AbstractA decoupled finite element method with different time steps for the nonstationary Darcy--Brinkman problem is considered in this paper. Moreover, for the presented method, the stability analysis and error estimates are deduced. Finally, numerical tests are provided that demonstrate the efficiency of the method. It is found the presented method can save lots of computational time compared with standard coupled method.

scholarly journals ANALISIS STABILITAS TEROWONGAN DANGKAL PADA TANAH LUNAK

2020 ◽  
Vol 1 (1) ◽  
pp. 573-584
Author(s):  
Putri Nova Haryu Dhanti ◽  
Singgih Saptono
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Soft Soil ◽  
Infrastructure Development ◽  
The Finite Element Method ◽  
Swelling Properties ◽  
Road Tunnels ◽  
The Stability ◽  
Element Method

ABSTRAK Pada lima tahun terakhir ini banyak pembangunan yang dilakukan di Indonesia khususnya pembangunan infrastruktur, seperti pembangunan sarana Mass Rapid Transportation (MRT) berupa terowongan di Jakarta, dan berapa terowongan jalan raya dan terowongan jalur kereta api. Hal ini menjadi tantangan bagi para pembuatan terowongan di Indonesia. Tantangan tesebut adalah membuat terowongan jalan raya dan kereta api pada tanah lunak khususnya lempung dan pada kedalaman yang dangkal. Hal ini perlu perhatian khusus, disebabkan oleh sifat lempung yang memiliki sifat swelling dan serta penggalian terowongan tersebut pada kedalamanan kurang dari 100 m. Pendekatan kekuatan batuan sudah tidak dapat digolongan sebagai batuan karena pada umumnya menurut meterial lempung digolongkan sebagai tanah, sehingga teori elastistas sudah tidak berlaku lagi. Pendekatan yang diusulkan untuk analisis stabilitas  pada terowongan di batuan lempung  adalah berperilaku swelling sesuai dengan kandungan mineral penyusunnya yaitu montmorilonit. Untuk itu analisis stabiltas diperlukan parameter swelling. Pada Analisis dengan perilaku sewlling ini menggunakan metode elemen hingga (Phase2, Rocscience). Dengan pendekatan perilaku Swelling dalam  analisis stabilitas terwongan akan lebih mendekati dengan sifat material yang ada di terowongan. Kata kunci: swelling, metode elemen hingga, stabilitas, terowongan  ABSTRACT In the last five years a lot of development has been carried out in Indonesia, especially infrastructure development, such as the construction of Mass Rapid Transportation (MRT) facilities in the form of tunnels in Jakarta, and how many road tunnels and railroad tunnels. This is a challenge for tunnels in Indonesia. The challenge is to build road and rail tunnels on soft soil, especially clays and at shallow depths. This needs special attention, due to the nature of the clay which has swelling properties and the excavation of the tunnel in the depth of less than 100 m. Rock strength approach can no longer be classified as rock because in general according to clay meterial classified as soil, so the theory of electricity is no longer valid. The proposed approach for the stability analysis of tunnels in clay rock is to behave swelling according to its constituent mineral content, montmorillonite. For this reason, stability analysis requires swelling parameters. In this analysis with sewlling behavior using the finite element method (Phase2, Rocscience). With the Swelling behavior approach in the tunnel stability analysis it will be closer to the material properties in the tunnel. Key words : Swelling, Finite Element Method, Stability, Tunnel 

Design and Stability Analysis of Latticed Shell Structure in Site of Tianluoshan

2012 ◽  
Vol 193-194 ◽  
pp. 864-867
Author(s):  
Wen Feng Du ◽  
Zhi Fei Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Shell Structure ◽  
Nonlinear Finite Element ◽  
Nonlinear Finite Element Method ◽  
Geometrical Nonlinear ◽  
The Stability ◽  
Element Method ◽  
Geometrical Nonlinear Finite Element

The design and analysis of the large span steel latticed shell structure in site of Yuyao TianLuoshan is introduced, and some key problems are dwelled on in this paper. By the geometrical nonlinear finite element method, the nonlinear stability analysis is carried out. The buckling modal and the whole course of instability are shown by two analysis method, the eigen-buckling analysis and the geometrical nonlinear finite element method. The influence of spring support to the stability of the structure is analyzed. It is shown that the structure has good wind-resisting capacity, which is fit to the circumstance near sea with lots of typhoon. Large compressive membrane stresses arise in the structure under the condition of temperature rise, leading to a significant reduction in the stability load-carrying capacity of the structure.

Stability Analysis of Composite Perforated Annular Sector Plates Under Thermomechanical Loading by Finite Element Method

2018 ◽  
Vol 18 (07) ◽  
pp. 1850100 ◽  
Author(s):  
Alireza Shaterzadeh ◽  
Hamed Behzad ◽  
Mohammad Shariyat
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Mechanical Load ◽  
Perforated Plate ◽  
Curvilinear Coordinates ◽  
Element Formulation ◽  
The Finite Element Method ◽  
The Stability ◽  
Element Method

This paper presents the stability analysis of a perforated plate with sector geometry made of composite materials. The sector of concern is a compound of graphite-epoxy and glass-epoxy with identical ply thickness but different fiber angles for each layer. The mechanical load conditions considered include uniform axial, circumferential, and biaxial pressure, while the thermal loading is specified to be uniform temperature increase over the whole sector. The existence of one or two circular holes has increased the complexity of analysis. To obtain solutions of high accuracy, the three-dimensional elasticity theory relations have been employed. Using the finite element method along with the stability condition of Trefftz, the buckling equation of the structure is derived. Green nonlinear strain-displacement relations are used to form the geometrical stiffness matrix. Unlike the finite element method used by other researches, a novel curved 3D B-Splined element is used to more accurately trace the displacement and stress variations of the structure. This element can be used in solution domains with geometric discontinuities, such as perforated plates and also meshed in the thickness direction. Moreover, instead of using the common von Karman assumptions, the most general form of the strain tensors in the curvilinear coordinates is adopted. The buckling load is obtained by extremizing the second variations of the total potential energy. The finite element formulation is coded in the MATLAB software. The effects of various parameters such as sector dimensions, dimensions of the hole, mechanical load directions, and fiber angles of each layer on the thermomechanical buckling is investigated.

scholarly journals The Least Squares Stochastic Finite Element Method in Structural Stability Analysis of Steel Skeletal Structures

2015 ◽  
Vol 20 (2) ◽  
pp. 299-318 ◽  
Author(s):  
M. Kamiński ◽  
J. Szafran
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Least Squares ◽  
Structural Reliability ◽  
Stochastic Finite Element Method ◽  
Stochastic Finite Element ◽  
Skeletal Structures ◽  
The Stability ◽  
Element Method

Abstract The main purpose of this work is to verify the influence of the weighting procedure in the Least Squares Method on the probabilistic moments resulting from the stability analysis of steel skeletal structures. We discuss this issue also in the context of the geometrical nonlinearity appearing in the Stochastic Finite Element Method equations for the stability analysis and preservation of the Gaussian probability density function employed to model the Young modulus of a structural steel in this problem. The weighting procedure itself (with both triangular and Dirac-type) shows rather marginal influence on all probabilistic coefficients under consideration. This hybrid stochastic computational technique consisting of the FEM and computer algebra systems (ROBOT and MAPLE packages) may be used for analogous nonlinear analyses in structural reliability assessment.

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