Mechanical Performance Research Articles

Experimental and numerical studies on the twisted-bending mechanical performance of stacked REBCO tapes in twist stacked-tape cable

Abstract Twisted stacked-tape cable in conduit conductor (TSTC-CICC) structures are highly promising due to their ease of fabrication, flexibility, and high current density. In practical applications, the tapes within the conductor experience a combination of torsion and bending, which directly influence their mechanical integrity and electrical performance. This study investigates the mechanical behavior of stacked REBCO tapes in a 6-slot TSTC-CICC, focusing on stress and strain responses under varying twist pitches and bending radii. A shell element-based REBCO tape composite model was developed, and both experimental tests and finite element analyses were conducted to evaluate the mechanical response of the tapes under torsional and bending loads. In the experimental phase, conductor samples with twist pitches of 200 mm and 300 mm were fabricated to examine the onset of mechanical degradation under torsion-bending conditions. The sample with a 200 mm twist pitch showed critical current degradation at a bending radius of 700 mm, while the sample with a 300 mm twist pitch exhibited similar degradation at 900 mm. A finite element analysis method was developed to simulate 3D stacked REBCO tapes under torsion-bending conditions. For computational efficiency, the tapes were simplified into a shell structure. The simulation results revealed that axial strain distribution at critical current degradation points was consistent across different twist pitches and bending radii, closely aligning with experimental findings. The simulation and experimental results suggest that relative sliding between tapes plays a key role in mitigating stress concentration, potentially improving the longevity and performance of the TSTC-CICC in practical applications.

Superhydrophobic PBAT/PLA Fibrous Membrane with Excellent Mechanical Performance for Highly Efficient Oil–Water Separation

Superhydrophobic PBAT/PLA Fibrous Membrane with Excellent Mechanical Performance for Highly Efficient Oil–Water Separation

Mechanical Performance of Polyampholyte Hydrogels Influenced by Ionic Bond Strength under Isochoric Conditions

Mechanical Performance of Polyampholyte Hydrogels Influenced by Ionic Bond Strength under Isochoric Conditions

Ag-Grid and Ag-Nanowires Hybrid Transparent Electrodes to Improve Performance of Flexible Organic Light-Emitting Devices

Flexible transparent conductive electrodes, with high optical transmittance, electrical conductivity, and flexible stability, still challenge the commercial development of flexible organic light-emitting devices (OLEDs). In this work, a novel Ag-grid and Ag-nanowire (Ag-grid/AgNW) hybrid transparent conductive film was proposed with extraordinary optoelectronic and mechanical performance. The hybrid film exhibited a low resistivity of 9 Ω/sq and a high transparency of 67.9% at the wavelength of 550 nm, as well as outstanding mechanical robustness by surviving over 5000 bending cycles. By applying the proposed Ag-grid/AgNW hybrid electrode in flexible OLEDs, the electroluminescence performance, flexibility, and mechanical reliability of the devices were significantly improved.

Ultrastrong eutectogels engineered via integrated mechanical training in molecular and structural engineering

Ultrastrong gels possess generally ultrahigh modulus and strength yet exhibit limited stretchability owing to hardening and embrittlement accompanied by reinforcement. This dilemma is overcome here by using hyperhysteresis-mediated mechanical training that hyperhysteresis allows structural retardation to prevent the structural recovery of network after training, resulting in simply single pre-stretching training. This training strategy introduces deep eutectic solvent into polyvinyl alcohol hydrogels to achieve hyperhysteresis via hydrogen bonding nanocrystals on molecular engineering, performs single pre-stretching training to produce hierarchical nanofibrils on structural engineering, and fabricates chemically cross-linked second network to enable stretchability. The resultant eutectogels display exceptional mechanical performances with enormous fracture strength (85.2 MPa), Young’s modulus (98 MPa) and work of rupture (130.6 MJ m−3), which compare favorably to those of previous gels. The presented strategy is generalizable to other solvents and polymer for engineering ultrastrong organogels, and further inspires advanced fabrication technologies for force-induced self-reinforcement materials.

Assessment of Precast Concrete Deterioration in Marine Environments Using Non-Destructive Methods

Concrete structures in marine environments face significant degradation due to reinforcement corrosion caused by chloride ingress and sulfate attack. Poor construction quality, inadequate standards, and suboptimal design can further accelerate deterioration. Non-destructive testing (NDT) has proven valuable for durability assessment, yet its application remains limited due to the complex microstructural characteristics of concrete. This study establishes a comprehensive procedure for evaluating precast concrete degradation in marine environments using multiple characterization techniques. Two precast concrete elements with different cement types, CEM II A-L 42.5R and CEM I 42.5 R/SR, were analyzed through compressive strength tests, open porosity measurements, mercury intrusion porosimetry (MIP), ultrasonic wave transmission, and scanning electron microscopy (SEM). The results indicate that CEM I 42.5 R/SR exhibits superior compressive strength and lower porosity, making it more durable and suitable for load-bearing applications. Higher ultrasonic pulse velocity (UPV) further confirms its resilience. In contrast, CEM II A-L 42.5R shows lower mechanical performance and greater susceptibility to marine-induced degradation. Over time, pore size distribution shifts, potentially compromising mechanical integrity. SEM analysis reveals gypsum and brucite formation in degraded regions, demonstrating microstructural changes due to seawater exposure. A strong negative correlation between porosity and UPV underscores the detrimental effect of increased porosity on material density and structural stability. This study highlights the effectiveness of UPV and porosity analysis as reliable NDT techniques for assessing concrete deterioration. The strong correlation between UPV and porosity trends suggests that UPV serves as an early indicator of durability loss, enabling timely maintenance interventions. These findings provide valuable insights into material selection for enhanced structural performance in marine environments and emphasize the role of NDT in long-term structural health monitoring.

Sustainable Earthen Construction: A Meta-Analytical Review of Environmental, Mechanical, and Thermal Performance

This study examines the main earthen constructions—such as adobe, compressed earth blocks (CEBs), and rammed earth walls (REWs)—highlighting their potential to reduce the environmental impact compared to conventional materials. Through a systematic literature review (2013–2024) and a meta-analysis, the mechanical, thermal, and sustainability properties of these constructions are analyzed. Emphasis is placed on the use of additives, such as stabilizers and fibers from various industrial and agro-industrial by-products, as leading actors influencing the mechanical and environmental performance of earthen constructions (EnCs). Remarkable improvements in the compressive and flexural strength are found, especially in stabilized CEBs and REWs, where strengths of up to 24 MPa are reached in certain mixtures, comparable to conventional materials such as concrete. However, the impact of these admixtures on environmental aspects, as measured through metrics such as the global warming potential (GWP), remains poorly documented. This review also shows that numerical methods like finite element modeling (FEM) have been crucial to modeling and predicting the performance of these materials, contributing to the understanding of their dynamic and structural responses. The findings suggest that, although CEB is currently the most studied onshore technique, future challenges include the standardization of admixtures and regulation of sustainable practices globally.

Friction stir welding of aluminum alloy 6082-T6 using eccentric shoulder tools to eliminate the need for tool tilting

The present research investigates the impact of eccentric shoulder tools on the microstructure and mechanical properties of friction stir welded (FSWed) aluminum alloy AA6082-T6. Two tools, one with an eccentric shoulder and one with an aligned shoulder, were employed under identical welding parameters: a rotational speed of 600 rpm, travel speed of 250 mm/min, and tilt angles of 0° and 3°. The four FSWed joints produced were characterized using optical microscopy, tensile testing, and hardness testing. The weld nugget zone (WNZ) microstructure showed significant grain size reduction from 5.24 μm for the base material to 1.63 μm, using the eccentric shoulder tool at 0° tilting angle and 2.78 μm at 3° tilting angle. The aligned shoulder tool resulted in an average grain size of 2.79 μm at 0° tilting angle and 2.23 μm of 3° tilting angle. Thus, the eccentric shoulder tool with a tilt angle of 0° exhibited the smallest average grain size. The mechanical properties obtained are consistent with the microstructure, where the joint produced using the eccentric shoulder at a 0° tilting angle showed the highest tensile strength of 216.5 MPa (89.7% joint efficiency) and 7.71% elongation. In contrast, the aligned shoulder tool resulted in coarser grains and a lower mechanical performance. In addition, this joint exhibited the highest hardness recovery in WNZ. The current study implies that the eccentric shoulder tool can eliminate the need for a tilting angle during FSW, which is required in some applications.

Compression and bending performance of selective laser melted Ti6Al4V porous structures with cylindrical thin walls for dental implants.

Titanium alloy dental implants play a crucial role in the field of oral rehabilitation. However, the use of solid designs can create mechanical issues such as mismatched compressive elastic modulus with the host bone tissue, resulting in stress shielding and stress concentration. These problems have been a persistent bottleneck in their application effectiveness. To overcome this challenge, this study creatively designed five types of porous structures with cylindrical thin wall based on the Gibson-Ashby theoretical model. The aim is to optimize the mechanical performance of dental implants, enhance their compatibility with the host bone tissue, and utilize selective laser melting technology for precise fabrication of porous structures using Ti6Al4V material. Through a combination of simulation analysis and compression experiments, the stress and strain distributions of the five structures are systematically investigated under different bite conditions. The experimental results demonstrate that all five porous structures designed in this study effectively alleviate stress shielding phenomenon in dental implants, significantly improving the bonding performance between the implants and bone tissue. This meets the clinical implantation requirements and provides strong theoretical support for the application of dental implants in clinical settings.&#xD.

Mechanically robust, flexible, conductive, and anti-freezing hydrogels reinforced by cellulose of wood skeleton.

Mechanically robust, flexible, conductive, and anti-freezing hydrogels reinforced by cellulose of wood skeleton.

Innovative Optimization of Mechanical Performance in Carbon Fiber-Reinforced Nylon Composite Using Artificial Neural Networks and Multi-Objective Genetic Algorithms

Innovative Optimization of Mechanical Performance in Carbon Fiber-Reinforced Nylon Composite Using Artificial Neural Networks and Multi-Objective Genetic Algorithms

Enhanced Mechanical Performance of Silicone Rubber Using Silica-Cellulose Hybrid Nanofibers with Strong Polymer–Filler Interactions

Enhanced Mechanical Performance of Silicone Rubber Using Silica-Cellulose Hybrid Nanofibers with Strong Polymer–Filler Interactions

A Comparative Analysis of ProTaper Ultimate and Five Multifile Systems: Design, Metallurgy, and Mechanical Performance

A Comparative Analysis of ProTaper Ultimate and Five Multifile Systems: Design, Metallurgy, and Mechanical Performance

Embedding polydopamine in keratin-based biohydrogels for efficient dye removal.

Embedding polydopamine in keratin-based biohydrogels for efficient dye removal.

Synergistic Enhancement of High-Strength Concrete's Mechanical Strength Through the Utilization of Steel, Synthetic, and Hybrid Fiber Systems

This investigation addresses the notable gap in understanding the effects of fiber hybridization on concrete performance. The study's primary objective is to enhance the mechanical characteristics of high-strength concrete by incorporating a blend of steel and synthetic fibers. A detailed examination of 192 specimens, categorized into eight distinct groups, was conducted. This analysis focused on the roles of macrosteel and PP fibers in preventing significant cracks and micro-PVA and PP fibers in managing smaller-scale cracking. These specimens underwent stringent testing processes to evaluate the impact of fiber content, limited to a 1% concentration for macrofibers, on the compressive strength (CS) and flexural tensile (FTS) strength of the concrete. The results reveal that integrating steel fibers into concrete mixtures marginally enhances the CS (typically by 4–8%). In contrast, the incorporation of microsynthetic fibers (namely, PVA and PP), was observed to decrease the CS. This finding underscores the complexities inherent in the interaction between fibers and concrete. To support these findings, the study employed advanced nonlinear modeling techniques, concentrating on the interplay between various fiber types and their contributions to concrete strength. The developed models exhibit considerable predictive accuracy. The models showed the significant effect of macro-PP fibers on CS, especially when combined with steel fiber of length 40 mm. This specific blend produces a synergistic effect, notably enhancing the concrete's strength. Overall, this research provides crucial insights into the optimization of fiber-reinforced concrete mixtures, advancing the field by proposing enhanced mechanical performance strategies.

Amorphization evolution study of CrCoFeNiMn high entropy alloy for mechanical performance optimization by deep potential molecular dynamics

In the study, we explore the structural evolution of Cantor high-entropy alloy (HEA) under different super-cooling rates and its correlation with mechanical property variations by the developed machine learning-driven deep potential molecular dynamics (DPMD) simulation. Our results reveal the critical super-cooling rate of amorphization-crystallization transition of Cantor alloy and the local structure constitutions at different temperatures during the super-cooling process. The associated mechanical property studies demonstrate the glassy Cantor alloy amorphized at high super-cooling rate exhibits a superior capability of ductility but this capability is unrelated to the amorphization cooling rates. While the high strength of Cantor alloy requires a lower super-cooling rate which might result in the crystallization, amorphizing the Cantor alloy at the critical super-cooling rate of amorphization-crystallization transition could compatibilize both ductility and strength capabilities. Such a discovery sheds new lights on the material development and its mechanical performance optimization for industrial applications.

Evaluation of the Mechanical Performance of Asphalt Mixtures Incorporated with Steel Slag and Recycled Concrete Aggregate

Evaluation of the Mechanical Performance of Asphalt Mixtures Incorporated with Steel Slag and Recycled Concrete Aggregate

Microstructural and statistical analysis on mechanical performance of novel flattened end nylon fibre reinforced concrete

This study investigates the use of novel flattened-end nylon fibres (FENF) as reinforcement in concrete to improve its mechanical properties. The research addresses inadequate circumferential bonding between macro synthetic fibres and concrete matrix, which can lead to fibre slippage or failure. Through experiments involving 19 concrete mixes with varying fibre dosages (0.5%, 1% and 1.5%), aspect ratios (35, 55 and 75), and shapes (straight and flattened-end), the study examines the impact of FENF on concrete workability and mechanical strengths. The mechanical strength tests illustrate the significance of fibre dosage, aspect ratio and especially the shape as the compressive, split-tensile strength and flexural strengths of the FENF concrete are respectively showing an increase in strength of up to 10.3%, 25.1% and 26.1% when compared with conventional concrete. Similarly, the straight nylon fibre-reinforced concrete also achieved comparable strength increments up to 11.8%, 13.9% and 15.9% respectively for compressive, split-tensile and flexural strengths. This indicates that the positive effect of fibre shape on circumferential bonding helped the better performance of the FENF in split-tensile and flexural strengths. Further, the statistical methods, including regression analysis, Principal Components Analysis, and Response Surface Methodology, are employed to analyse the complex relationships between fibre characteristics and identify optimal fibre configurations. Using the Scanning Electron Microscope (SEM) the microstructural view has been studied to evaluate the interaction between FENF and the concrete matrix.

What about anterior endocrowns?

Fehrenbach J, de Soares J L S, do Nascimento Foly J C S, Miotti L L, Münchow E A Mechanical performance of endocrown restorations in anterior teeth: A systematic review and network meta-analysis. Dent Mater 2025; https://doi.org/10.1016/j.dental.2024.10.012 . A systematic review and network meta-analysis (NMA) of anterior endocrown mechanical performance compared to conventional crowns on endodontically treated teeth (ETT). An online search of major databases was conducted and relevant studies were selected. Data was extracted and meta-analyses performed comparing mechanical outcomes of anterior endocrowns to other crown systems. Endocrowns on the anterior dentition can be considered if mechanical fracture is a concern, however more research needs to be done before definitive case selection. Two independent reviewers searched six electronic databases (PubMed, Scopus, Web of Science, Embase, SciELO and LILACS) using compounded terms like ETT and anterior and endocrown along with their variates. Manual searches were also done from the reference list of chosen studies. Following the search titles were put through Rayyan, an AI-powered systematic reviewer to remove duplicates. The reviewers then screened 25 random titles and abstracts independently and repeated this with a third reviewer. Inclusion criteria were studies examining anterior ETT and endocrown compared with a different restoration. Exclusion criteria were non-experimental studies, theses, languages other than English Spanish or Portuguese and studies not evaluating mechanical performance. From this 24 studies were read in full and 11 were selected for the review. Bias risk assessment was done by two reviewers using the RoBDEMAT tool for in vitro studies and ROBFEAD tool for Finite Element Analysis (FEA) studies. The studies are scored as low, med, or high risk according to each tool's domains. Two reviewers extracted the data onto Microsoft Excel including authors name and year of publication, tooth type, endocrown depth, distance between the CEJ and finishing line,surface treatment, luting agent, thermocycling method, etc. Data synthesis and analysis was performed by MetaInsight V4 4.0.0 and two independent NMA's were made. The first NMA used load-to-fracture data and a mean difference outcome while the second used irreparable fracture data and a risk ratio outcome. Both used a 95% credible interval(Crl). Comparisons were evaluated using Surface Under the Cumulative ranking Curve (SUCRA), where a value closer to 100% indicates greater resistance to fracture. Eight studies used in vitro experiments, most of them investigating load-to-fracture and failure mode of fractured restorations and one study the pull-out bond strength. The remaining three studies used FEA models and examined von mises criterion by quantifying a material's fracture under stress. The first NMA considered load-to-fracture data and examined five studies. The probabilistic analysis showed teeth restored with a Glass Fibre Post (GFP) and composite crown performed best (SUCRA = 95.23%), with higher load-to-fracture values (MD 165.0, 95% CRL 28.3, 301.0) than the Composite endocrown group (MD 78.1 95% Crl 6.21, 150.0). Lowest ranking was the GFP plus ceramic crown group, with ceramic endocrowns and ceramic crowns without post in between. The second NMA analysed irreparable fracture data from five studies. The composite endocrown group showed a lower catastrophic fracture risk (RR 0.413, 95% Crl 0.152, 0.859) compared to the GFP ceramic crown group (RR 1.36, 95% Crl 1.09, 1.80). Probabilistic analysis shows composite endocrowns with the lowest risk of irreparable fracture (SUCRA = 96.84%), followed by ceramic crown with no core, ceramic endocrowns and GFP crown groups with the highest risk. Endocrowns may be a viable choice for endodontically treated anterior teeth because they perform similarly to other restorative systems under mechanical load in lab and model scenarios. GRADE rating is low due to high risk of bias.

Production of Novel Dental Resin Monomers usingDimethacrylated Oligoesters Derived from Chemically Recycling PET waste.

This research explores the potential exploitation of recycled PET bottles in developing dimethacrylated oligoesters to be used as alternative monomers to produce novel dimethacrylate-based dental resins. Specifically, oligoester diols derived from PET glycolysis were converted into dimethacrylated oligoesters (PET-GLY-DMs), as alternative monomers to Bisphenol-A glycidyl methacrylate (Bis-GMA). The glycolysis products were analyzed for their molecular weight using GPCand the successful conversion of hydroxyl to methacrylate groups via methacrylation was confirmed by FT-IR spectroscopy. A gradient substitute of Bis-GMA by PET-GLY-DM within Bis-GMA/TEGDMA mixtures was conducted, and the gained dimethacrylated matrices were light-cured followed by the evaluation of their physicochemical and mechanical properties. It was revealed that the newly synthesized resins exhibited lower viscosity, higher degree of conversion, and reduced mechanical properties compared to the control resins. However, the most important observation, related to environmental friendliness, was that the PET-GLY-DMs did not release Bisphenol-A, as measured by liquid chromatography. The proportions of PET-GLY-DMs, Bis-GMA, and TEGDMA in dental resin formulations were optimized to achieve similar handling properties to control resins while maintaining significant hardening and mechanical performance. This research highlights the sustainability of the chemical recycling of PET, in the synthesis of novel products with added environmental and economic benefit.