Forced transverse vibration of Rayleigh and Timoshenko double-beam system with effect of compressive axial load

The free transverse vibration of an elastically connected axially loaded double beam system for different materials and geometry were measured experimentally and analyzed theoretically. The theory predicts that natural frequencies of the system are composed of two infinite sets, describing in-phase and out-of-phase vibrations. It is observed, for the case of identical beams, that the in-phase frequencies are independent of the elastic foundation stiffness and its frequencies are identical to a single beam with the same boundary conditions. To compare and verify the accuracy and reliability of theoretical models, experimental measurements of natural frequencies of free vibration of axially tensioned, double beams interconnected by a silicone rubber foundation with fixed-fixed supported conditions are conducted. The first four synchronous natural frequencies were measured, and they were found to increase with increasing tension. The experiments showed that the synchronous natural frequencies of axially tensioned double beam system with fixed-fixed end conditions are in excellent agreement with those for a tensioned single beam with the same end conditions. The asynchronous mode frequencies are not observed, and believed to be due to the existence of damping properties in the elastic foundation, which suppressed the out-of-phase (asynchronous) mode frequencies.

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Photoelastic Analysis on Different Retention Methods of Implant-Supported Prosthesis

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-12-00200 ◽

2015 ◽

Vol 41 (3) ◽

pp. 258-263 ◽

Cited By ~ 1

Author(s):

Angélica Castro Pimentel ◽

Marcello Roberto Manzi ◽

Cristiane Ibanhês Polo ◽

Claudio Luiz Sendyk ◽

Maria da Graça Naclério-Homem ◽

...

Keyword(s):

Stress Distribution ◽

Axial Load ◽

Testing Machine ◽

Compressive Load ◽

Lower Intensity ◽

Photoelasticity Method ◽

Universal Testing ◽

Isochromatic Fringes ◽

Photoelastic Analysis ◽

Compressive Axial Load

The aim of this study was to evaluate the stress distribution of different retention systems (screwed, cemented, and mixed) in 5-unit implant-supported fixed partial dentures through the photoelasticity method. Twenty standardized titanium suprastructures were manufactured, of which 5 were screw retained, 5 were cement retained, and 10 were mixed (with an alternating sequence of abutments), each supported by 5 external hexagon (4.0 mm × 11.5 mm) implants. A circular polariscope was used, and an axial compressive load of 100 N was applied on a universal testing machine. The results were photographed and qualitatively analyzed. We observed the formation of isochromatic fringes as a result of the stresses generated around the implant after installation of the different suprastructures and after the application of a compressive axial load of 100 N. We conclude that a lack of passive adaptation was observed in all suprastructures with the formation of low-magnitude stress in some implants. When cemented and mixed suprastructures were subjected to a compressive load, they displayed lower levels of stress distribution and lower intensity fringes compared to the screwed prosthesis.

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Exact dynamic characteristic analysis of a double-beam system interconnected by a viscoelastic layer

Composites Part B Engineering ◽

10.1016/j.compositesb.2018.11.043 ◽

2019 ◽

Vol 163 ◽

pp. 272-281 ◽

Cited By ~ 20

Author(s):

Fei Han ◽

Danhui Dan ◽

Wei Cheng

Keyword(s):

Dynamic Characteristic ◽

Viscoelastic Layer ◽

Characteristic Analysis ◽

Beam System ◽

Double Beam

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Analysis of Shear-critical reinforced concrete columns under variable axial load

Magazine of Concrete Research ◽

10.1680/jmacr.21.00034 ◽

2022 ◽

pp. 1-24

Author(s):

Dimitrios K. Zimos ◽

Panagiotis E. Mergos ◽

Vassilis K. Papanikolaou ◽

Andreas J. Kappos

Keyword(s):

Reinforced Concrete ◽

Axial Load ◽

Shear Failure ◽

Progressive Collapse ◽

Full Range ◽

Element Model ◽

Independent Verification ◽

Lateral Response ◽

Proposed Model ◽

Compressive Axial Load

Older existing reinforced concrete (R/C) frame structures often contain shear-dominated vertical structural elements, which can experience loss of axial load-bearing capacity after a shear failure, hence initiating progressive collapse. An experimental investigation previously reported by the authors focused on the effect of increasing compressive axial load on the non-linear post-peak lateral response of shear, and flexure-shear, critical R/C columns. These results and findings are used here to verify key assumptions of a finite element model previously proposed by the authors, which is able to capture the full-range response of shear-dominated R/C columns up to the onset of axial failure. Additionally, numerically predicted responses using the proposed model are compared with the experimental ones of the tested column specimens under increasing axial load. Not only global, but also local response quantities are examined, which are difficult to capture in a phenomenological beam-column model. These comparisons also provide an opportunity for an independent verification of the predictive capabilities of the model, because these specimens were not part of the initial database that was used to develop it.

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