The analysis of buckling and post buckling in the compressed composite columns

2017 ◽  
Vol 85 (1) ◽  
pp. 35-41 ◽  
Author(s):  
P. Wysmulski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Eigenvalue Problem ◽  
Critical Load ◽  
Critical State ◽  
Numerical Models ◽  
Equilibrium Path ◽  
Critical Equilibrium ◽  
Thin Walled ◽  
Element Method

Purpose: The aim of the study was to analyse the work of a thin-walled C-shaped profile, made of a carbon-epoxy composite, which was subjected to unified axial compression. Design/methodology/approach: The scope of the study included the analysis of the critical and low post-critical state by the use of numerical and experimental methods. As a result of the experimental test, performed on the physical specimen, post-critical equilibrium path had been determined, on the basis of which, with use of the adequate approximation method critical load value was defined. The next stage of the research was devoted to numerical analysis based on the finite element method. The studies were carried out on a scope of the linear analysis of the eigenvalue problem, on the basis of witch the critical value of load for mathematical model was found. The next step of the numerical tests was covering the nonlinear analysis of the low post-critical state for the model with geometrical imperfection, corresponding to the lowest form of buckling. Findings: The result of the study was to determine the value of the critical load, on the basis of the experimentally obtained post-critical equilibrium paths of the structure, with use of two independent methods of Approximation: Koiter's method and the method of the vertical tangent. The results of the analysis were compared with the value of the critical load determined by using finite element method. Research limitations/implications: The obtained results of study provide the important information concerning the modelling techniques of the thin-walled structures made of composite materials, while confirming the adequacy of the numerical models developed both in the calculation of eigenvalue problem, as well as non-linear static analysis in the post-critical range. Originality/value: The research provided the necessary knowledge of the behaviour of the critical and low post-critical of the thin-walled structure made of modern orthotropic material (CFRP).

scholarly journals Finite Element Analysis of Thermoelastic Contact Stability

1994 ◽  
Vol 61 (4) ◽  
pp. 919-922 ◽  
Author(s):  
Taein Yeo ◽  
J. R. Barber
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Steady State ◽  
Eigenvalue Problem ◽  
Linear Perturbation ◽  
Dimensional System ◽  
The Finite Element Method ◽  
One Dimensional ◽  
Thermoelastic Contact ◽  
Element Method

When heat is conducted across an interface between two dissimilar materials, theimoelastic distortion affects the contact pressure distribution. The existence of a pressure-sensitive thermal contact resistance at the interface can cause such systems to be unstable in the steady-state. Stability analysis for thermoelastic contact has been conducted by linear perturbation methods for one-dimensional and simple two-dimensional geometries, but analytical solutions become very complicated for finite geometries. A method is therefore proposed in which the finite element method is used to reduce the stability problem to an eigenvalue problem. The linearity of the underlying perturbation problem enables us to conclude that solutions can be obtained in separated-variable form with exponential variation in time. This factor can therefore be removed from the governing equations and the finite element method is used to obtain a time-independent set of homogeneous equations in which the exponential growth rate appears as a linear parameter. We therefore obtain a linear eigenvalue problem and stability of the system requires that all the resulting eigenvalues should have negative real part. The method is discussed in application to the simple one-dimensional system of two contacting rods. The results show good agreement with previous analytical investigations and give additional information about the migration of eigenvalues in the complex plane as the steady-state heat flux is varied.

scholarly journals Optimization of a thin-walled element geometry using a system integrating neural networks and finite element method

2017 ◽  
Vol 62 (1) ◽  
pp. 435-442 ◽  
Author(s):  
P. Golewski ◽  
J. Gajewski ◽  
T. Sadowski
Keyword(s):  
Neural Networks ◽  
Finite Element Method ◽  
Finite Element ◽  
Artificial Neural Networks ◽  
Integrated System ◽  
Multilayer Perceptrons ◽  
Optimization Of Geometry ◽  
Thin Walled ◽  
Artificial Neural ◽  
Element Method

Abstract Artificial neural networks [ANNs] are an effective method for predicting and classifying variables. This article presents the application of an integrated system based on artificial neural networks and calculations by the finite element method [FEM] for the optimization of geometry of a thin-walled element of an air structure. To ensure optimal structure, the structure’s geometry was modified by creating side holes and ribs, also with holes. The main criterion of optimization was to reduce the structure’s weight at the lowest possible deformation of the tested object. The numerical tests concerned a fragment of an elevator used in the “Bryza” aircraft. The tests were conducted for networks with radial basis functions [RBF] and multilayer perceptrons [MLP]. The calculations described in the paper are an attempt at testing the FEM - ANN system with respect to design optimization.

scholarly journals Studies of thin-walled parts deformation by gripping force during turning process on an example of bearing ring

2018 ◽  
Vol 244 ◽  
pp. 02010
Author(s):  
Adam Patalas ◽  
Michał Regus ◽  
Katarzyna Peta
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Turning Process ◽  
Turning Operation ◽  
Geometrical Accuracy ◽  
Bearing Ring ◽  
Thin Walled ◽  
Gripping Force ◽  
Element Method

In this paper thin-walled part deformation during finishing turning process caused by gripping force of hydraulic lathe chuck was investigated. Bearing ring was taken as an example of thin-walled part undergo finishing turning operation. Finite Element Method (FEM) was used to define the deformation of examined part. The aim of presented research was to compare the deformation of bearing ring caused by gripping force of hydraulic 3-jaw chuck and 6-jaw chuck for different values of total gripping force. The data obtained from conducted simulations allowed to evaluate the influence of gripping force on machining part deformation which is directly related with its geometrical accuracy.

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