Contact Mechanics of UV/Ozone-Treated PDMS by AFM and JKR Testing: Mechanical Performance from Nano- to Micrometer Length Scales

2008 ◽  
Vol 41 (18) ◽  
pp. 6757-6762 ◽  
Author(s):  
Jing Song ◽  
Davide Tranchida ◽  
G. Julius Vancso
Keyword(s):  
Contact Mechanics ◽  
Mechanical Performance ◽  
Length Scales ◽  
Uv Ozone

Structured Abrasive CMP: Length Scales, Subpads, and Planarization

1999 ◽  
Vol 566 ◽  
Author(s):  
D. P. Goetz
Keyword(s):  
Contact Mechanics ◽  
Elastic Foundation ◽  
Chemical Mechanical Planarization ◽  
Minimum Length ◽  
Length Scale ◽  
Uniform Compression ◽  
Length Scales ◽  
Process Pressure ◽  
Edge Exclusion ◽  
Minimum Length Scale

Chemical-Mechanical Planarization with structured abrasive uses a subpad to manage the pressure variations due to loading over a range of length scales. The effect of subpad construction on pressure responses related to those scales is illustrated.A minimum length scale for the effect of the subpad is established via contact mechanics. Differences between one- and two-layer subpads are shown. Uniform compression, point loading, and edge exclusion are considered briefly. A model of the subpad as a plate on an elastic foundation is applied to the problem of die doming. The roles of process pressure, die size, and subpad construction are illustrated. Planarization at the intra-die, die, and wafer scales are related to the subpad construction.

Critical length scales and strain localization govern the mechanical performance of multi-layer graphene assemblies

Nanoscale ◽  
2016 ◽  
Vol 8 (12) ◽  
pp. 6456-6462 ◽  
Author(s):  
Wenjie Xia ◽  
Luis Ruiz ◽  
Nicola M. Pugno ◽  
Sinan Keten
Keyword(s):  
Strain Localization ◽  
Mechanical Performance ◽  
Critical Length ◽  
Deformation Mechanisms ◽  
Length Scales ◽  
Layer Graphene ◽  
Constitutive Response

Three critical length scales govern the deformation mechanisms and constitutive response of multi-layer graphene.

scholarly journals A Review on Tough Soft Composites at Different Length Scales

Textiles ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 513-534
Author(s):  
Wei Cui ◽  
Ruijie Zhu
Keyword(s):  
Mechanical Performance ◽  
Synergistic Effects ◽  
High Strength ◽  
Soft Materials ◽  
Design Strategy ◽  
Toughening Mechanism ◽  
Design Strategies ◽  
Length Scales ◽  
Mechanical Responses ◽  
High Toughness

Soft composites are widely employed in industrial and biomedical fields, which often serve as load-bearing structural materials by virtue of a special combination of high strength, high toughness, and low flexural stiffness. Understanding the toughening mechanism of such composites is crucial for designing the next-generation soft materials. In this review, we give an overview of recent progress in soft composites, focusing on the design strategy, mechanical properties, toughening mechanisms, and relevant applications. Fundamental design strategies for soft composites that dissipate energy at different length scales are firstly described. By subsequently elucidating the synergistic effects of combining soft and hard phases, we show how a resulting composite can achieve unprecedented mechanical performance by optimizing the energy dissipation. Relevant toughening models are discussed to interpret the superior strength and fracture toughness of such soft composites. We also highlight relevant applications of these soft composites by taking advantage of their special mechanical responses.

A Multi-Scale Model for Bending Stiffness of CNT Strands in CNT Fibers

2017 ◽  
Author(s):  
Ali Imani Azad ◽  
Roozbeh Dargazany ◽  
Reza Mirzaeifar ◽  
Shankar Mall
Keyword(s):  
Carbon Nanotube ◽  
Electrical Properties ◽  
Load Transfer ◽  
Mechanical Performance ◽  
Scale Model ◽  
Length Scales ◽  
Multi Scale ◽  
Mechanical And Electrical Properties ◽  
Load Transfer Mechanism ◽  
Void Area

Carbon Nanotube (CNT) fibers are 3D-woven hierarchical assemblies of CNTs which show excellent mechanical and electrical properties. There is a tremendous loss of mechanical performance in the scale transition from individual CNT to fibers, over which we have limited understanding. Our knowledge of load transfer across different length scales is scarce and inconclusive. Here, the objective is to explore the load transfer mechanism (LTM) of CNT fibers, by identifying the contribution of defects on mechanical performance of fibers at various length scales. A micromechanical-based constitutive model is developed to describe bending-tensile properties of strands as an assembly of twisted yarns. The model associates the strand response to two states of deformation referred to as stick and slip states. Several inelastic features were considered in calculation of the response of strands, such as local jamming, evolution of the void area between yarns, and friction. The model is validated against different sets of experiments.

Enhancing the power generation of Rhodopseudomonas palustris-based MFC

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1261-1268
Author(s):  
Shu Otani ◽  
Dang-Trang Nguyen ◽  
Kozo Taguchi
Keyword(s):  
Activated Carbon ◽  
Rhodopseudomonas Palustris ◽  
Ozone Treatment ◽  
Maximum Power Density ◽  
On Demand ◽  
Long Time ◽  
Dry Conditions ◽  
Carbon Sheet ◽  
Uv Ozone

In this study, a portable and disposable paper-based microbial fuel cell (MFC) was fabricated. The MFC was powered by Rhodopseudomonas palustris bacteria (R. palustris). An activated carbon sheet-based anode pre-loaded organic matter (starch) and R. palustris was used. By using starch in the anode, R. palustris-loaded on the anode could be preserved for a long time in dry conditions. The MFC could generate electricity on-demand activated by adding water to the anode. The activated carbon sheet anode was treated by UV-ozone treatment to remove impurities and to improve its hydrophilicity before being loaded with R. palustris. The developed MFC could generate the maximum power density of 0.9 μW/cm2 and could be preserved for long-term usage with little performance degradation (10% after four weeks).

The Mechanical Performance of Carbon Fibres- Addressing the Role of Microstructure

2019 ◽  
Author(s):  
Peter Peter ◽  
Claudia Creighton ◽  
David Fox ◽  
Pablo Mota Santiago ◽  
Adrian Hawley ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Carbon Fibres

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

NUMERICAL STUDY ON THE MECHANICAL PERFORMANCE OF GRAPHENE BRIDGES ON SILLICON THIN FILM TRANSISTORS

2011 ◽  
Author(s):  
Byung-Jae Kim ◽  
Hyeon-Seok Seo ◽  
Won-Ho Lee ◽  
Jong-Hyun Ahn ◽  
Youn-Jea Kim
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Mechanical Performance ◽  
Numerical Study
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