Bachiller

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Buckling
Introduction
This tutorial was created using ANSYS 7.0 to solve a simplebuckling problem. It is recommended that you complete the NonLinear Tutorial prior to beginning this tutorial Buckling loads are critical loads where certain types of structures become unstable. Eachload has an associated buckled mode shape; this is the shape that the structure assumes in a buckled condition. There are two primary means to perform a buckling analysis: 1. Eigenvalue Eigenvaluebuckling analysis predicts the theoretical buckling strength of an ideal elastic structure. It computes the structural eigenvalues for the given system loading and constraints. This is known asclassical Euler buckling analysis. Buckling loads for several configurations are readily available from tabulated solutions. However, in real-life, structural imperfections and nonlinearitiesprevent most realworld structures from reaching their eigenvalue predicted buckling strength; ie. it over-predicts the expected buckling loads. This method is not recommended for accurate, real-worldbuckling prediction analysis. 2. Nonlinear Nonlinear buckling analysis is more accurate than eigenvalue analysis because it employs non-linear, large-deflection, static analysis to predict bucklingloads. Its mode of operation is very simple: it gradually increases the applied load until a load level is found whereby the structure becomes unstable (ie. suddenly a very small increase in theload will cause very large deflections). The true non-linear nature of this analysis thus permits the modeling of geometric imperfections, load perterbations, material nonlinearities and gaps. Forthis type of analysis, note that small off-axis loads are necessary to initiate the desired buckling mode.

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