Coupled bending and torsional vibrations of non-uniform thin-walled beams by the transfer differential transform method and experiments. (June 2018)

• Record Type: Journal Article
• Authors: Zhou, Jingwei; Wen, Shurui; Li, Fengming; Zhu, Yu
• Is Part Of: Thin-walled structures. Volume 127(2018)
• Page Start: 373
• Page End: 388
• Publication Date: 2018-06
• Subjects: Bending and torsional vibrations -- Non-uniform thin-walled beams -- Transfer matrix method -- Differential transform method -- Modal test; Thin-walled structures -- Periodicals; 690.1
• DOI: 10.1016/j.tws.2018.02.026
• Languages: English
• ISSNs: 0263-8231

Abstract

Abstract: This paper describes a new methodology capable of analyzing coupled bending and torsional vibrations in non-uniform thin-walled beams. The transfer matrix method (TMM) and the differential transform method (DTM) are combined to create the proposed transfer differential transform method (TDTM) for solving equations coupling bending and torsional vibrations in non-uniform beams. Compared with the finite element method (FEM), the TDTM utilizes a type of changeable mode shape functions so that the number of meshed elements can be reduced greatly when the beam's geometric size is uniform. The equations of motion of the non-uniform thin-walled beams are established using Hamilton's principle. The method considers both the warping and rotary effects of the beam section. The natural frequencies and mode shapes of the bending and torsional components are obtained using the TDTM. The accuracy of solutions can be controlled by the mesh density and the series expansion order of the mode shape whose ranges are also discussed. For illustrative purposes, the natural frequencies and the frequency response curves of a uniform beam and a non-uniform beam are studied respectively and are validated by experiments. The effects of warping and the distance between the centroid of a given section and the corresponding shear center on the vibration properties of the beam are also investigated. Highlights: Coupled bending and torsional vibrations in non-uniform beams are studied. Warping and rotary effects of the beam are taken into account in the model. Frequency responses are computed and validated by experiments and FEM. Transfer matrix and differential transform methods are combined in the study.