Precision Element Method for Free Vibration Analysis of Rotational Shells with Partial Viscoelastic Core

2013 ◽  
Vol 634-638 ◽  
pp. 3778-3781
Author(s):  
Jing Lu

Based on the elastic thin shell and layer wise theories, the first order differential matrix equation of a PCLD rotational shell is formulated. According to the principles of the finite element method and precision integration technology, a semi-analytical method, named precision element method, for the free vibration characteristic of a PCLD rotational shell is developed. Numerical results show that the present method is accurate and efficient.

2018 ◽  
Vol 4 (2) ◽  
pp. 61
Author(s):  
Yaprak Itır Özdemir

The purpose of this paper is to study free vibration analysis of thick plates resting on Winkler foundation using Mindlin’s theory with first order finite element, to determine the effects of the thickness/span ratio, the aspect ratio, subgrade reaction modulus and the boundary conditions on the frequency parameters of thick plates subjected to free vibration. In the analysis, finite element method is used for spatial integration. Finite element formulation of the equations of the thick plate theory is derived by using first order displacement shape functions. A computer program using finite element method is coded in C++ to analyze the plates free, clamped or simply supported along all four edges. In the analysis, 4-noded finite element is used. Graphs are presented that should help engineers in the design of thick plates subjected to earthquake excitations. It is concluded that 4-noded finite element can be effectively used in the free vibration analysis of thick plates. It is also concluded that, in general, the changes in the thickness/span ratio are more effective on the maximum responses considered in this study than the changes in the aspect ratio.


Aviation ◽  
2010 ◽  
Vol 14 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Tadeusz Markowski ◽  
Stanislaw Noga ◽  
Stanislaw Rudy

The development of computer techniques and computational systems based on the finite element method allows one to conduct a free vibration analysis of large systems like an aviation gearbox test rig. The object of this paper is to present a free vibration analysis of a gear fatigue test rig working in a closed loop configuration. A numerical model of the test rig based on the finite element method is presented in this paper. The base model contains all the essential structures of the real system. After the numerical results of the natural frequencies of the rig were obtained, they were then verified by the experimental results on a real object. Numerical analysis was performed using the ANSYS code. Santrauka Baigtiniu elementu metodu paremtas kompiuterines technikos ir kompiuteriniu sistemu kūrimas leidžia atlikti laisvuju svyravimu analize tokios dideles sistemos, kaip aviacines pavaru dežes, testavimo irenginys. Šio darbo tikslas buvo atlikti pavaru dežes nuovargio bandymu irenginio, veikiančio uždaro kontūro konfigūracijoje, laisvuju svyravimu analize. Taip pat pateikiamas testavimo irenginio skaitinis modelis, kurio veikimas yra pagristas baigtiniu elementu metodu. Pagrindinis modelis turi visas tikrosios sistemos svarbiausias struktūras. Gavus irenginio savuju dažniu kiekybinius rezultatus, buvo patikrinti realaus objekto eksperimentiniai rezultatai. Naudojantis ANSYS sistema buvo atlikta skaitine analize.


2000 ◽  
Vol 14 (6) ◽  
pp. 633-644 ◽  
Author(s):  
Jin-Rae Cho ◽  
Jin-Kyu Lee ◽  
Jeong-Mok Song ◽  
Suk-Ho Park ◽  
Joong-Nam Lee

2005 ◽  
Vol 02 (02) ◽  
pp. 255-269 ◽  
Author(s):  
S. M. HAMZA-CHERIF

A p-version of the finite element method is applied to free vibration analysis of rotating beams in conjunction with the modeling dynamic method using the arc-length stretch deformation. In this study the flexible and the rigid body degrees of freedom (d.o.f.) are supposedly uncoupled, the linear equations of motion are derived for flapwise and chordwise bending with the integration of the gyroscopic effect. The hybrid displacements are expressed as the combination of the in-plane and out-of-plane shape functions. These are formulated in terms of linear and cubic polynomial functions used generally in FEM in addition to a variable number of trigonometric shape functions which represent the internal d.o.f. for the rotating flexible beams. The convergence properties of the rotating beam Fourier p-element and the influence of angular speed, boundary conditions and slenderness ratio on the dynamic response are studied. It is shown that using this element the order of the resulting matrices in the FEM is considerably reduced leading to a significant decrease in computational effort.


Sign in / Sign up

Export Citation Format

Share Document