Free Vibration Analysis of Thin-Walled Cylinders Reinforced With Longitudinal and Transversal Stiffeners

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
E. Carrera ◽  
E. Zappino ◽  
M. Filippi
Keyword(s):  
Degrees Of Freedom ◽  
Free Vibration Analysis ◽  
The Finite Element Method ◽  
Cylindrical Structures ◽  
One Dimensional ◽  
Computational Costs ◽  
Thin Walled Structures ◽  
Carrera Unified Formulation ◽  
Thin Walled ◽  
Good Agreement

This paper deals with the dynamic analysis of reinforced thin-walled structures by means of refined one-dimensional models. Complex reinforced structures are considered which are built by using different components: skin, ribs, and stringers. Higher-order one-dimensional model based on the Carrera unified formulation (CUF) are used to model panels, stringer, and ribs by referring to a unique model. The finite element method (FEM) is used to provide a solution that deals with any boundary condition configuration. The structure is geometrically linear and the materials are isotropic and elastic. The dynamic behavior of a number of reinforced thin-walled cylindrical structures have been analyzed. The effects of the reinforcements (ribs and stringers) are investigated in terms of natural frequencies and modal-shapes. The results show a good agreement with those from commercial codes by reducing the computational costs in terms of degrees of freedom (DOFs).

Dynamic Analysis of Fracture in Thin-Walled Pipes

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
C. Gato ◽  
Y. Shie
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Fracture ◽  
Meshfree Method ◽  
Meshfree Methods ◽  
Shape Functions ◽  
Order Continuity ◽  
Cylindrical Structures ◽  
Thin Walled Structures ◽  
Ill Conditioning ◽  
Thin Walled

Dynamic fracture of thin-walled cylindrical structures is studied with a large deformation meshfree method. Due to the higher order continuity and smoothness of the shape functions, meshfree methods are well suited to simulate dynamic fracture of thin-walled structures since they avoid ill-conditioning as well as stiffening in numerical computations. Simulations of detonation driven fracture in thin pipes demonstrate the efficiency of the method.

A Component-Wise Approach to Analyse a Composite Launcher Structure Subjected to Loading Factor

2016 ◽  
Author(s):  
Tommaso Cavallo ◽  
Alfonso Pagani ◽  
Enrico Zappino ◽  
Erasmo Carrera
Keyword(s):  
Composite Structures ◽  
Computational Cost ◽  
Free Vibration Analysis ◽  
High Strength ◽  
3D Models ◽  
Advanced Materials ◽  
Space Structures ◽  
One Dimensional ◽  
Computational Costs ◽  
The One

The space structures are realized by combining skin and reinforced components, such as longitudinal reinforcements called stringers and transversal reinforcements called ribs. These reinforced structures allow two main design requirements to be satisfied, the former is the light weight and the latter is a high strength. Solid models (3D) are widely used in the Finite Element Method (FEM) to analyse space structures because they have a high accuracy, in contrast they also have a high number of degrees of freedoms (DOFs) and huge computational costs. For these reasons the one-dimensional models (1D) are gaining success as alternative to 3D models. Classical models, such as Euler-Bernoulli or Timoshenko beam theories, allow the computational cost to be reduced but they are limited by their assumptions. Different refined models have been proposed to overcome these limitations and to extend the use of 1D models to the analysis of complex geometries or advanced materials. In this work very complex space structures are analyzed using 1D model based on the Carrera Unified Formulation (CUF). The free-vibration analysis of isotropic and composite structures are shown. The effects of the loading factor on the natural frequencies of an outline of launcher similar to the Arian V have been investigated. The results highlight the capability of the present refined one-dimensional model to reduce the computational costs without reducing the accuracy of the analysis.

scholarly journals APPLICATION OF SUPERELEMENTS IN STATIC ANALYSIS OF THIN‐WALLED STRUCTURES

2004 ◽  
Vol 10 (2) ◽  
pp. 113-122
Author(s):  
Ireneusz Kreja ◽  
Tomasz Mikulski ◽  
Czeslaw Szymczak
Keyword(s):  
Static Analysis ◽  
Standard Procedure ◽  
Dimensional Model ◽  
Fem Model ◽  
Shell Elements ◽  
One Dimensional ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Proper Solutions

A concept of a beam superelement is suggested as a new tool in the static analysis of structures made of thin‐walled members. This proposal seems to be especially attractive for treating the problems where the existing one‐dimensional models do not provide proper solutions. This class of problems includes, for instance, the torsion of thin‐walled beams with battens and the determination of the bimoment distribution at the nodes of frames made of thin‐walled members. The entire segment of the thin‐walled beam with warping stiffener or the whole node of the frame is modelled with shell elements. The stiffness matrix of such thin‐walled beam superelement can be estimated according to the standard procedure of the enforced unit displacements. The accuracy of the proposed one‐dimensional model has proved to be comparable to that offered by the detailed FEM model where the whole structure is represented by a very large number of shell elements.

Analysis of thin-walled frames considering joint flexibilities

2007 ◽  
Vol 221 (10) ◽  
pp. 1221-1229 ◽  
Author(s):  
P R Marur
Keyword(s):  
Beam Theory ◽  
Frame Structure ◽  
Elastic Response ◽  
Joint Flexibility ◽  
One Dimensional ◽  
Static And Dynamic Analysis ◽  
Out Of Plane ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Good Agreement

TAnalytical models are developed for static and dynamic analysis of thin-walled frames representing the automotive side structures. The model is based on one-dimensional beam theory that considers joint flexibility to compute stiffness and frequency response of the whole frame structure. The computed out-of-plane displacements under static and impact loading are in good agreement with those obtained from the shell finite element method. Using the validated analytical model, the influence of joint flexibility on the elastic response of the side structure is studied.

Accurate fracture analysis of electrically permeable/impermeable cracks in one-dimensional hexagonal piezoelectric quasicrystal junction

2019 ◽  
Vol 24 (12) ◽  
pp. 4032-4050 ◽  
Author(s):  
Zhenting Yang ◽  
Xiong Yu ◽  
Wang Xu ◽  
Chenghui Xu ◽  
Zhenhuan Zhou ◽  
...  
Keyword(s):  
Electric Displacement ◽  
Fracture Analysis ◽  
The Finite Element Method ◽  
Crack Face ◽  
Impermeable Crack ◽  
One Dimensional ◽  
Fracture Parameters ◽  
Small Set ◽  
Singular Domain ◽  
Good Agreement

An accurate fracture analysis of a multi-material junction of one-dimensional hexagonal quasicrystals with piezoelectric effect is performed by using Hamiltonian mechanics incorporated in the finite element method. Two idealized electrical assumptions, including electrically permeable and impermeable crack-face conditions, are considered. In the Hamiltonian system, the analytical solutions to the multi-material piezoelectric quasicrystal around the crack tip (singular domain) are obtained and expressed in terms of symplectic eigensolutions. Therefore, the large number of nodal unknowns in the singular domain is reduced into a small set of undetermined coefficients of the symplectic series. The unknowns in the non-singular domain remain unchanged. Explicit expressions of phonon stresses, phason stresses, and electric displacement in the singular domain and newly defined fracture parameters are achieved simultaneously. Comparisons are presented to verify the proposed approach and very good agreement is reported. The key influencing parameters of the crack are discussed in detail. The effects of electrical assumptions and positions of the crack on the fracture parameters are discussed in detail.

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