Isoparametric finite element of a composite shell with double approximation of strains

1992 ◽  
Vol 27 (5) ◽  
pp. 581-585 ◽  
Author(s):  
A. I. Golovanov ◽  
I. Yu. Krasnovskii
Keyword(s):  
Finite Element ◽  
Composite Shell ◽  
Isoparametric Finite Element ◽  
Double Approximation

scholarly journals An Optimum Fatigue Design of Polymer Composite Compressed Natural Gas Tank Using Hybrid Finite Element-Response Surface Methods

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 483
Author(s):  
Kazem Reza Kashyzadeh ◽  
Seyed Saeid Rahimian Koloor ◽  
Mostafa Omidi Bidgoli ◽  
Michal Petrů ◽  
Alireza Amiri Asfarjani
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Natural Gas ◽  
Response Surface ◽  
Polymer Composite ◽  
Wall Thickness ◽  
Composite Shell ◽  
Compressed Natural Gas ◽  
Fiber Angle ◽  
Composite Tank

The main purpose of this research is to design a high-fatigue performance hoop wrapped compressed natural gas (CNG) composite cylinder. To this end, an optimization algorithm was presented as a combination of finite element simulation (FES) and response surface analysis (RSA). The geometrical model was prepared as a variable wall-thickness following the experimental measurements. Next, transient dynamic analysis was performed subjected to the refueling process, including the minimum and maximum internal pressures of 20 and 200 bar, respectively. The time histories of stress tensor components were extracted in the critical region. Furthermore, RSA was utilized to investigate the interaction effects of various polymer composite shell manufacturing process parameters (thickness and fiber angle) on the fatigue life of polymer composite CNG pressure tank (type-4). In the optimization procedure, four parameters including wall-thickness of the composite shell in three different sections of the CNG tank and fiber angle were considered as input variables. In addition, the maximum principal stress of the component was considered as the objective function. Eventually, the fatigue life of the polymer composite tank was calculated using stress-based failure criterion. The results indicated that the proposed new design (applying optimal parameters) leads to improve the fatigue life of the polymer composite tank with polyethylene liner about 2.4 times in comparison with the initial design.

Modal Analysis of the Axial Compressor Blade: Advanced Time-Dependent Electronic Interferometry and Finite Element Method

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mykhaylo Tkach ◽  
Serhii Morhun ◽  
Yuri Zolotoy ◽  
Irina Zhuk
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Finite Element ◽  
High Reliability ◽  
Axial Compressor ◽  
Time Dependent ◽  
Experimental Setup ◽  
Vibration Modes ◽  
Compressor Blades ◽  
Isoparametric Finite Element

AbstractNatural frequencies and vibration modes of axial compressor blades are investigated. A refined mathematical model based on the usage of an eight-nodal curvilinear isoparametric finite element was applied. The verification of the model is carried out by finding the frequencies and vibration modes of a smooth cylindrical shell and comparing them with experimental data. A high-precision experimental setup based on an advanced method of time-dependent electronic interferometry was developed for this aim. Thus, the objective of the study is to verify the adequacy of the refined mathematical model by means of the advanced time-dependent electronic interferometry experimental method. The divergence of the results of frequency measurements between numerical calculations and experimental data does not exceed 5 % that indicates the adequacy and high reliability of the developed mathematical model. The developed mathematical model and experimental setup can be used later in the study of blades with more complex geometric and strength characteristics or in cases when the real boundary conditions or mechanical characteristics of material are uncertain.

2-D electromagnetic modeling by finite‐element method with a dipole source and topography

Geophysics ◽  
2000 ◽  
Vol 65 (2) ◽  
pp. 465-475 ◽  
Author(s):  
Yuji Mitsuhata
Keyword(s):  
Finite Element ◽  
Delta Function ◽  
Dipole Source ◽  
Electromagnetic Modeling ◽  
Secondary Field ◽  
Controlled Source ◽  
Transient Electromagnetic ◽  
Isoparametric Finite Element ◽  
Anomalous Bodies ◽  
Element Technique

I present a method for calculating frequency‐domain electromagnetic responses caused by a dipole source over a 2-D structure. In modeling controlled‐source electromagnetic data, it is usual to separate the electromagnetic field into a primary (background) and a secondary (scattered) field to avoid a source singularity, and only the secondary field caused by anomalous bodies is computed numerically. However, this conventional scheme is not effective for complex structures lacking a simple background structure. The present modeling method uses a pseudo‐delta function to distribute the dipole source current, and does not need the separation of the primary and the secondary field. In addition, the method employs an isoparametric finite‐element technique to represent realistic topography. Numerical experiments are used to validate the code. Finally, a simulation of a source overprint effect and the response of topography for the long‐offset transient electromagnetic and the controlled‐source magnetotelluric measurements is presented.

Transient Response Analysis of Geometrically Nonlinear Laminated Composite Shell Structures

1996 ◽  
Author(s):  
Cho W. S. To ◽  
Bin Wang
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Composite Shell ◽  
Laminated Composite ◽  
Shell Structures ◽  
Response Analysis ◽  
Hybrid Strain ◽  
Drilling Degree Of Freedom ◽  
Shell Finite Element ◽  
Shear Deformable

Abstract The investigation reported in this paper is concerned with the prediction of geometrically large nonlinear responses of laminated composite shell structures under transient excitations by employing the hybrid strain based flat triangular laminated composite shell finite element presented here. Large deformation of finite strain and finite rotation are considered. The finite element has eighteen degrees-of-freedom which encompass the important drilling degree-of-freedom at every node. It is hinged on the first order shear deformable lamination theory. Various laminated composite shell structures have been studied and for brevity only two are presented here. It is concluded that the element proposed is very accurate and efficient. Shear locking has not appeared in the results obtained thus far. There is no zero energy mode detected in the problems studied. For nonlinear dynamic response computations, the full structural system has to be considered if accurate results are required.

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