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Power series expansion of the general stiffness matrix for beam elements
Author(s) -
Paz Mario,
Dung Lam
Publication year - 1975
Publication title -
international journal for numerical methods in engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.421
H-Index - 168
eISSN - 1097-0207
pISSN - 0029-5981
DOI - 10.1002/nme.1620090212
Subject(s) - direct stiffness method , stiffness matrix , power series , tangent stiffness matrix , mathematical analysis , stiffness , matrix (chemical analysis) , series (stratigraphy) , mathematics , taylor series , series expansion , structural engineering , materials science , engineering , paleontology , composite material , biology
The general stiffness matrix for a beam element is derived from the Bernoulli–Euler differential equation with the inclusion of axial forces. The terms of this matrix are expanded into a power series as a function of the two variables: the axial force, and; the vibrating frequency. It is shown that the first three terms of the resulting series, which are derived in the technical literature from assumed static displacement functions, correspond respectively to the elastic stiffness matrix, the consistent mass matrix, and the geometric matrix. Higher order terms up to the second order terms of the series expansion are obtained explicitly. Also a discussion is presented for establishing the region of convergence of the series expansion for the dynamic stiffness matrix, the stability matrix, and the general stiffness matrix.