Saudi Journal of Civil Engineering (SJCE)
Volume-2 | Issue-02 | 110-119
Original Research Article
Least Squares Weighted Residual Method for the Elastic Buckling of Euler Column with Fixed-Pinned Ends
Ikwueze EU, Ike CC, Ofondu IO
Published : Oct. 30, 2018
Abstract
The least squares weighted residual method was used in this work to solve
the boundary value problem (BVP) of an Euler column of length l fixed at x = 0, and
pinned at x = l. Polynomial shape (spline) functions for Euler columns with fixedpinned ends were used to obtain one – and two parameter buckling shape functions in
terms of unknown generalised parameters. The one and two parameter buckling shape
functions were used to construct least squares weighted residual integral statements of
the boundary value problem. The least squares weighted residual statements
simplified the boundary value problem (BVP) to algebraic eigenvalue – eigenvector
problems. The solution for non trivial cases yielded characteristic buckling equations
which were solved to obtain the buckling loads. One parameter coordinate shape
function yielded the critical load as Qcr = 21EI/l2, while the two parameter buckling
shape function yielded Qcr = 20.34614EI/l2. One parameter least squares weighted
residual solution yielded a relative error of 4 % while the two parameter least squares
weighted residual solution yielded a relative error of 0.77% compared to the exact
solution.