Objective: The aim of this in vitro study was to determine the load and deflection at failure of different lingual retainers bonded with composite to enamel in a standardized three-point bending test. The results were rationalized with finite element analysis (FEA) models.
Materials And Methods: Four types of multistranded wires, Dead Soft Respond, Twisted ligature, Penta-One, Gold-plated Penta-One, and two glass fibre-reinforced composite retainers, Fibre 07 and Fibre 09, were bonded to enamel with composite and submitted to a three-point bending test. The load and deflection at failure and the mode of debonding were recorded. The stiffness of the wires was determined and all experimental data were used in FEA models to rationalize the observed values and mode of debonding.
Results: Significant higher load and deflection were found for the most flexible retainers Twisted ligature and Dead Soft Respond. All retainers failed between the wire and composite, which was confirmed by FEA showing the highest stress in the composite around the retainer. The FEA models showed that the amount of composite used for bonding the retainers should be 2-4mm.
Conclusions: Based on the in vitro results, optimal bonding of lingual retainers can be achieved by flexible retainers, bonded with intrinsically strong composites. According to the FEA models the retainer should be bonded with 2-4mm composite, leaving the critical 'free-wire' length for the success of the retainer system.
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http://dx.doi.org/10.1093/ejo/cju074 | DOI Listing |
Sci Rep
January 2025
Institute of the Malay World and Civilisation (ATMA), Universiti Kebangsaan Malaysia (UKM), 43600, Bangi, Selangor, Malaysia.
The adoption of pultruded glass fibre-reinforced polymer (pGFRP) composites as a substitute for traditional wooden cross-arms in high transmission towers represents a relatively novel approach. These materials were selected for their high strength-to-weight ratio and lightweight properties. Despite various studies focusing on structures improvement, there still have a significant gap in understanding the deformation characteristics of full-scale cross-arms under actual operational loads.
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January 2025
School of Perceptual Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
This paper presents a flat-type piezoelectric motor utilizing in-plane vibration modes. Two piezoelectric ceramic plates in combination with a brass metal sheet were used to construct the stator. The superposition of two second order in-plane vibration modes can generate a traveling-wave inside the stator.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Key Laboratory of New Technology for Construction of Cities in Mountain Area, School of Civil Engineering, Chongqing University, Chongqing 400000, China.
According to the mechanical characteristics of joints in steel-concrete composite bridge decks under the combined bending and shear, improved joint details with simple structure and convenient construction were studied, including lapped U-bars, lapped headed bars, and lapped hook bars. In order to test the mechanical properties of the three joint details and compare them with the existing lapped/welded linear bars, the tests of five specimens were carried out. The cracking load, ultimate load, failure mode, crack pattern, and reinforcement strain were analyzed.
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December 2024
School of Civil Engineering, Zhengzhou University, Zhengzhou 450001, China.
This research investigates the flexural performance of slabs reinforced with high-strength steel-strand mesh (HSSM) and engineered cementitious composites (ECCs). By employing finite element analysis (FEA) and theoretical modeling, this study aims to deepen the understanding of how these materials behave under bending stresses. A finite element model was developed to simulate the nonlinear behavior of ECCs during bending, considering critical elements such as tensile and compressive damage, as well as bond-slip interactions between the steel strands and the ECCs.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Department of Civil Engineering, Higher Institute of Engineering and Technology, Kafr El-Sheikh 35516, Egypt.
In this study, shear-critical reinforced concrete (RC) beams were strengthened by combining the prestressing and near-surface mounted (NSM) rods approaches. The potential danger of failure in such RC beams is a substantial concern as it is considered a potential threat. This study addresses its careful mitigation through experimental identification and numerical analysis to enhance the safety and sustainability of buildings by reducing the probability of failure risk for these RC beams.
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