Solution of Solid Mechanic Equilibrium Problems by Power Series

Solution of Solid Mechanic Equilibrium Problems by Power Series

E. González M. Sarrazin

Universidad de Chile, School of Engineering, Chile

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The paper presents the application of power series to the numerical solution of equilibrium problems in elasticity. Complete bases of power series that satisfy the differential equations are developed, first for unidimensional problems like the equilibrium of a beam on elastic foundation, second for the harmonic differential equation in two dimensions, with application to the Saint-Venant’s torsion problem and, finally, for the biharmonic equation, which can be applied to plane elasticity problems as well as to the plate-bending problem. In the case of unidimensional problems the solution is exact, because the number of boundary conditions is equal to the number of parameters involved in the series expansion, whereas in the two-dimensional problems the solution satisfies exactly the differential equation but only approximately the boundary conditions. The approximation of the solution will depend on the number of points selected at the boundary. The method presented here can also be used for developing high-order finite elements of any number of nodes and boundary shapes using complete polynomial expansions that satisfy the differential equation. Selected practical applications are shown.


Beam on elastic foundation, biharmonic equation, boundary conditions, equilibrium problems, finite elements, harmonic equation, plane elasticity, plate-bending problem, power series, Saint-Venant’s torsion problem


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