Dynamic properties of unbonded, multi-strand beams subjected to flexural loading. (15th February 2018)

• Record Type: Journal Article
• Authors: Asker, Haval K.; Rongong, Jem A.; Lord, Charles E.
• Is Part Of: Mechanical systems and signal processing. Volume 101(2018)
• Page Start: 168
• Page End: 181
• Publication Date: 2018-02-15
• Subjects: Friction -- Damping -- Multi-strand -- Loss factor -- Energy dissipation -- Three point bend; Structural dynamics -- Periodicals; Vibration -- Periodicals; Constructions -- Dynamique -- Périodiques; Vibration -- Périodiques; Structural dynamics; Vibration; Periodicals; 621
• DOI: 10.1016/j.ymssp.2017.08.028
• Languages: English
• ISSNs: 0888-3270

Abstract

Highlights: Beams constructed from square steel strands experiencing frictional contact. Loss factors not significantly affected by frequency. For the same overall dimensions, increasing numbers of strands reduces stiffness. Energy dissipation not significantly affected by the number of strands. Simulations based on the Coulomb friction model match experiments. Abstract: Beam-like structures, constructed from many long strands that are constrained rather than bonded together, can provide appreciable levels of structural damping through friction between individual strands. This paper describes experimental and numerical studies, carried out on square-section metal beams, which are aimed at improving understanding of the relationship between construction and performance. A beam is formed from a pack of square-section strands that is held together at various compression loads with pre-calibrated clamps. Flexural deformation of the assembled beam is simulated using standard finite element analysis employing simple Coulomb friction at the interfaces. The validity of the assumptions used in the models is confirmed by comparison with three point bend tests on a regular nine strand construction at several different clamp loads. Dynamic loss factors for this beam are obtained by conducting forced vibration tests, which show that the damping is insensitive to frequency. Subsequent numerical studies are used to investigate the effects of increasing the number of strands whilst maintaining the overall cross-section geometry of the beam. It is found that the system stiffness drops and loss factor increases when more strands are used for a maintained beam cross-section. Interestingly, the energy dissipated by each beam construction is almost the same. These results provide a vital and necessary insight into the physics for stranded structures and materials that are largely prevalent in mechanical (e.g. cables) and electrical (e.g. wires) elements.