Structural Dynamic and Aeroelastic Finite Element Simulation of an F-18 Tail Rudder: Impact of Adding a Control Surface

2005 ◽  
Author(s):  
Kevin R. Anderson ◽  
Kevin White ◽  
Wayne McEntire
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Control Surface ◽  
Maximum Pressure ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Torsional Mode ◽  
Bending Mode ◽  
Aeroelastic Simulations ◽  
Bending Modes

This paper presents the findings of a Finite Element Analysis (FEA) based aeroelastic analysis performed on the F-18 tail rudder using MacNeal-Schwendler (MSC) suite of commercial FEA codes. The purpose of the study was to examine the stabilizing effects of adding a control surface to the tail wing, in this case the control surface is the tail rudder. MSC NASTRAN modal analysis and aeroelastic simulations were employed to carry out the investigation. Results are presented herein for the fundamental modes subject to a structural dynamics analysis and a series of supersonic 4G rolling maneuvers. Without a control surface, modal analysis yielded the following; 1st bending mode = 17.098 Hz, 1st torsional mode = 53.879 Hz, 2nd bending mode = 80.531 Hz, and 2nd torsional mode = 117.15 Hz. By adding the of rudder, the following is found; 1st bending mode = 17.797 Hz, 1st torsional mode = 48.266 Hz, 2nd torsional mode = 61.267 Hz, and 2nd bending mode = 81.142 Hz. Hence, adding the control surface, changes the precedence of the 2nd torsional and 2nd bending modes. Aeroelasticity predictions show that for a 100% increase in Mach number, the maximum pressure on the control surface increases by 93%.

Improved Results in Structural Dynamic Calculations by Linking Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA)

1995 ◽  
Author(s):  
Ulrich Gabbert ◽  
Manfred Zehn ◽  
Friedrich Wahl
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Numerical Models ◽  
Mass Matrix ◽  
Computer Time ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Element Analysis ◽  
Structural Dynamic

Abstract The paper deals with improvements of accuracy of structural dynamic calculations by using both the advantages of Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA). The basis for such improvements are reasonable mechanical and numerical models and accurate frequency response measurements (eigenfrequencies and mode shapes). The paper deals first with reasons for and estimations of errors in numerical and experimental analysis. It can be shown by theory and experiment that neither FEA nor EMA models are unique, due to inevitable incompleteness of the mode shapes and eigenfrequencies from a vibration test. Verification and updating of FE models by linking FEA with EMA are discussed in the paper and mainly focussed on FE models with a large number of degrees of freedom. Hence an update method has been introduced, which leads to an improved model in a relatively small quantity of computer time. It can be shown, that based on measured eigenfrequencies and calculated eigenvectors, an updating of FE-models for real engineering problems, by changing the mass matrix only, is a very efficient procedure with a surprisingly good quality updated model.

Dynamic Characterization of Car Door and Hood Panels Using FEA and EMA

2013 ◽  
Vol 471 ◽  
pp. 89-96 ◽  
Author(s):  
Zahir Hanouf ◽  
Waleed F. Faris ◽  
Mohd Jailani Mohd Nor
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Properties ◽  
Experimental Modal Analysis ◽  
Modal Testing ◽  
Dynamic Characterization ◽  
Element Analysis ◽  
Structural Dynamic

The dynamic characterization of vehicle structures is a crucial step in NVH analysis and helps in refining the vibration and noise in new vehicles. This paper investigates the dynamic properties of two parts of the vehicle structure which are door and hood panels. Theoretical modal analysis which is referred to as Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA) or modal testing has been used as investigative tools. The paper investigates the structural dynamic properties of door and hood panels of a local car. ME'scope software was used to analyze the data obtained from Pulse to extract the dynamic properties of the panels. LS-DYNA software was used to analyze the dynamic behavior of the structure. The comparison between the results obtained from both analyses showed some similarity in frequencies and mode shapes. Finally the paper concludes that experimental modal analysis and finite element analysis can both be used to extract dynamic properties of structures.

scholarly journals Inlay-Retained Dental Bridges—A Finite Element Analysis

2021 ◽  
Vol 11 (9) ◽  
pp. 3770
Author(s):  
Monica Tatarciuc ◽  
George Alexandru Maftei ◽  
Anca Vitalariu ◽  
Ionut Luchian ◽  
Ioana Martu ◽  
...  
Keyword(s):  
Finite Element ◽  
Young Patients ◽  
Maximum Pressure ◽  
Class Iii ◽  
Element Analysis ◽  
Dental Prostheses ◽  
Abutment Teeth ◽  
Fixed Dental Prostheses ◽  
Implant Therapy ◽  
The Stability

Inlay-retained dental bridges can be a viable minimally invasive alternative when patients reject the idea of implant therapy or conventional retained full-coverage fixed dental prostheses, which require more tooth preparation. Inlay-retained dental bridges are indicated in patients with good oral hygiene, low susceptibility to caries, and a minimum coronal tooth height of 5 mm. The present study aims to evaluate, through the finite element method (FEM), the stability of these types of dental bridges and the stresses on the supporting teeth, under the action of masticatory forces. The analysis revealed the distribution of the load on the bridge elements and on the retainers, highlighting the areas of maximum pressure. The results of our study demonstrate that the stress determined by the loading force cannot cause damage to the prosthetic device or to abutment teeth. Thus, it can be considered an optimal economical solution for treating class III Kennedy edentation in young patients or as a provisional pre-implant rehabilitation option. However, special attention must be paid to its design, especially in the connection area between the bridge elements, because the connectors and the retainers represent the weakest parts.

Interval Finite Element Analysis of Structural Dynamic Problems

2015 ◽  
Vol 8 (2) ◽  
pp. 382-389 ◽  
Author(s):  
Naijia Xiao ◽  
Rafi L. Muhanna ◽  
Francesco Fedele ◽  
Robert L. Mullen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Problems ◽  
Element Analysis ◽  
Structural Dynamic

Stochastic Dynamic Analysis of Structures with Spatially Uncertain Material Parameters

2014 ◽  
Vol 14 (08) ◽  
pp. 1440029 ◽  
Author(s):  
Kheirollah Sepahvand ◽  
Steffen Marburg
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Polynomial Chaos ◽  
Element Model ◽  
Stochastic Dynamic ◽  
Stochastic Field ◽  
Structural Dynamic ◽  
Material Parameters ◽  
Material Uncertainties ◽  
Stochastic Dynamic Analysis

This paper investigates the uncertainty quantification in structural dynamic problems with spatially random variation in material and damping parameters. Uncertain and locally varying material parameters are represented as stochastic field by means of the Karhunen–Loève (KL) expansion. The stiffness and damping properties of the structure are considered uncertain. Stochastic finite element of structural modal analysis is performed in which modal responses are represented using the generalized polynomial chaos (gPC) expansion. Knowing the KL expansions of the random parameters, the nonintrusive technique is employed on a set of random collocation points where the structure deterministic finite element model is executed to estimate the unknown coefficients of the polynomial chaos expansions. A numerical case study is presented for a cantilever beam with random Young's modulus involving spatial variation. The proportional damping constants are estimated from the experimental modal analysis. The expected value, standard deviation, and probability distribution of the random eigenfrequencies and the damping ratios are evaluated. The results show high accuracy compared to the Monte-Carlo (MC) simulations with 3000 realizations. It is also demonstrated that the eigenfrequencies and the damping ratios are equally affected from material uncertainties.

The Finite Element Modal Analysis of Spur Gear Based on Patran

2014 ◽  
Vol 962-965 ◽  
pp. 2957-2960
Author(s):  
Qian Peng Han ◽  
Bo Peng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Spur Gear ◽  
Parametric Model ◽  
Parametric Modeling ◽  
Element Analysis ◽  
General Process

This article summarized the general process of parametric modeling and finite element analysis of spur gear,PRO/E used to create parametric model,and Patran used to finite element analysis.Parametric modeling can reduce design period of the similar products,and modal analysis provide the basis for the selection and optimization of gear.

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