Approximate analytical analysis of longitudinal natural frequencies of a cracked beam

Abstract

Purpose

In this paper, an approximate analytical approach is developed for the determination of natural longitudinal frequencies of a cantilever-cracked beam based on the Lagrange inversion theorem.

Design/methodology/approach

The crack is modeled by an equivalent axial spring with stiffness according to Castigliano's theorem. Thus, an implicit frequency equation corresponding to cantilever-cracked bar is obtained. The resulting equation is solved using the Lagrange inversion theorem.

Findings

Effect of different crack depths and crack positions on natural frequencies of the cracked beam is analyzed. It is shown that an increase in the crack depth ratio produces a decrease in the fundamental longitudinal natural frequency of a cracked bar. Furthermore, approximate analytical results are compared with those obtained numerically as well as from experimental tests.

Originality/value

A new approximate analytical expression of a fundamental longitudinal frequency, as a function of crack depth and crack location, is obtained.

Citation

Ayas, H., Amara, L. and Chabaat, M. (2021), "Approximate analytical analysis of longitudinal natural frequencies of a cracked beam", International Journal of Structural Integrity, Vol. 12 No. 4, pp. 534-547. https://doi.org/10.1108/IJSI-07-2020-0065