Modal characteristics of cracked thin walled unsymmetrical cross-sectional steel beams curved in plan

The paper aims to develop a generalized Finite Element (FE) model for multiple cracked thin-walled curved beams by taking account of the warping effects in the cracked section. Modal features such as natural frequencies and mode shapes for cracked and uncracked curved beam have been presented for sections having one axis of symmetry and with no axis of symmetry for various crack parameters. Theoretical results have been validated by laboratory vibration test on steel channel and angle section beams. The study reveals that cracked curved thin-walled beams behave differently under vibratory load compared to that with straight beams. •Modal features of thin walled unsymmetrical cross sectional curved beams having cracks are investigated.•Finite element model of curved thin walled element with cracks is developed incorporating warping effect.•Experimental and theoretical results are presented for beams of channel and angle cross sections.•Although fundamental mode is governed by flexure, higher mode is dominated by torsion or combined mode.