Technical note: Exact composite beam element easily

Abstract

In reference [1] (J. Aalto, Technical note: Exact elements easily, Journal of Structural Mechanics, Vol. 56, No. 4, 2023, pp. 199–204), a simple technique for forming exact beam elements systematically and with minimum effort was presented. In this article, the technique is applied to a composite beam with a flexible connection. The analytical solution of the beam in terms of integration constants is derived, and relations between generalized displacement and force degrees of freedom and integration constants are obtained. By using these relations, the element stiffness matrix and load vector and exact distributions of generalized displacements and forces inside the element can be easily determined. As a numerical example, a two span composite beam under point load and own weight is presented.