Identification of Noise Sources in an Aircraft Fuselage Using an Inverse Method Based on a Finite Element Model

2011 ◽  
Vol 97 (6) ◽  
pp. 974-983 ◽  
Author(s):  
Thomas Kletschkowski ◽  
Matthias Weber ◽  
Delf Sachau
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Inverse Method ◽  
Element Model ◽  
Noise Sources ◽  
Aircraft Fuselage

Mechanical response of a panel section with a hexagonally tessellated stiffener grid

2016 ◽  
Vol 231 (8) ◽  
pp. 1402-1414
Author(s):  
M Bouazizi ◽  
T Lazghab ◽  
M Soula
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mechanical Response ◽  
Element Model ◽  
External Loading ◽  
Original Structure ◽  
Hexagonal Grid ◽  
Aircraft Fuselage ◽  
Stiffened Shells ◽  
Analytical Expressions

Stringers are stiffening members of pressurized aircraft fuselage. They provide support to the fuselage’s skin. A new stringer grid concept is proposed for conventional aircraft fuselage. Optimization is used to find the hexagonal grid that best replaces the original while keeping the same total stringer length. A finite element model is built to analyze the optimal hexagonal grid stiffened structure and compare it with the original orthogonally stiffened structure in terms of eigenfrequencies and static response to external loading. The finite element model is validated through Flugge’s analytical expressions for stiffened shells. Results show that the hexagonal grid stiffened structure yields higher eigenfrequencies with stresses and displacements comparable with that of the original structure.

scholarly journals The method of synthesis of finite-element model of strengthened fuselage frames

2013 ◽  
pp. 80-90
Author(s):  
В. В. Борисов ◽  
В. В. Сухов
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Model ◽  
User Interfaces ◽  
Element Model ◽  
Finite Element Models ◽  
Synthesis Algorithm ◽  
Model Synthesis ◽  
Aircraft Fuselage ◽  
The Finite Element Model

One of the main problems, which solved during the design of transport category aircraft, is problem of analysis of the stress distribution in the strengthened fuselage frames structure. Existing integral methods of stress analysis does not allow for the mutual influence of the deformation of a large number of elements. The most effective method of solving the problem of analysis of deformations influence on the stress distribution of structure is finite element method, which is a universal method for analyzing stress distribution arbitrary constructions.This article describes the features of the finite element model synthesis of the strengthened fuselage frames structure of the aircraft fuselage transport category. It is shown that the finite element model of strengthened frames can be synthesized by attaching additional finite element models of the reinforcing elements to the base finite element model which is built by algorithm which is developed for normal frame. For each reinforcing element developed a separate class of finite element model synthesis algorithm. The method of synthesis of finite element model of strengthened frame, which are described in this article, developed for object-oriented information technology implemented in an object-oriented data management system "SPACE".Finite-element models of the reinforcing elements are included in the finite element model of the fuselage box after the formation of a regular finite element model of the fuselage box. As the source data for the synthesis of finite element models of the reinforcing elements used the coordinates of the boundary sections nodes of existing finite element models of conventional frames.Reinforcing elements belong to the group of irregular structural elements that connect regular elements of the cross set with different elements that are not intended for the perception and transmission of loads. The only exceptions are the vertical amplification increasing the stiffness of  frames in a direction parallel to the axis OY.Source data input for the synthesis of finite element models of the reinforcing elements can occur only through the individual user interfaces that supported by objects of the corresponding classes. Structure of user interfaces depends on the number and type of additional data that required for the synthesis of finite element models of the reinforcing elements. For example, for the synthesis of structures of finite element models of horizontal beams that support the floor of cargo cabin, you must specify the distance between the upper surface of the beam and the horizontal axis of the fuselage, as well as the height of the beam section. For the synthesis of the structure of the finite element model of vertical reinforcing element is enough to specify the distance between the its inner belt and the a vertical axis of symmetry of the fuselage.And in both cases you must to specify a reference to the basic finite element model, by selecting from a list of frame designations. List of frames, as well as links to objects containing the appropriate finite-element models, must be transmitted from an object which references to the level of decomposition, in which the general model of the fuselage box is created.Finite-element models of the reinforcing elements include two groups of nodes. The first group is taken from an array of nodes, which is transmitted from the base finite element model. The second group is formed by the synthesis algorithm of finite element model of the selected class reinforcing element. Therefore, the synthesis of finite element models of the reinforcing elements starts with the formation of their local model versions. On the basis of these models are formed temporary copies, which are transmitted to the general finite element model of the box. This should be considered when developing of data conversion algorithm of data copying from a local finite element model to the temporary copy.Based on this analysis, we can conclude that this method improves the quality of the design of the aircraft fuselage, increasing the amount of structure variant number and reduce the likelihood of errors.

The Influences of Complex Impact Conditions on Aircraft Fuselage Crashworthiness

2012 ◽  
Vol 184-185 ◽  
pp. 546-552 ◽  
Author(s):  
Tian Chun Zou ◽  
Xiao Min Zhang ◽  
Hao Lei Mou ◽  
Zhen Yu Feng
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Characteristics ◽  
Vertical Velocity ◽  
Element Model ◽  
Roll Angle ◽  
Aircraft Structure ◽  
Aircraft Fuselage ◽  
Acceleration History ◽  
The Impact

In this paper, a certain B737 aircraft fuselage section was used to research the influence of different impact conditions on fuselage dynamic characteristics. A finite element model of fuselage was built up from FS380 to FS500. The impact responses of fuselage subjected to 9.133m/s vertical velocity were analyzed under the conditions of 0° roll angle, 10° left roll angle and combination acceleration. The differences of transformation and acceleration history curves under different conditions were compared. The research results show that the performances of 10° left roll angle will change fuselage transformation and acceleration of seats location, the appears of combination acceleration will increase transformation of floor and decrease acceleration at the seats location. The crashworthiness of aircraft structure can be effectively improved by selecting the appropriate landing way.

An Inverse Method to Measure the Complex Dynamic Moduli of Elastomers

2002 ◽  
Author(s):  
Yves H. Berthelot ◽  
Lei Wu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Material Properties ◽  
Inverse Method ◽  
Element Model ◽  
Surface Velocity ◽  
Complex Dynamic ◽  
Dynamic Moduli ◽  
Large Defect

The dynamic moduli of elastomers are estimated from measurements of the surface velocity of a 3D sample. The measured values are matched with predictions from a finite element model in which the material properties are adjustable parameters. The sensitivity of the inversion technique to the locations of the measurements is discussed. Numerical simulations indicate that the method might be used to determine the moduli of two isotropic layers bonded together. Results also indicate the possibility of detecting the presence of a large defect in the sample.

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