Mechanical Design of Antichiral-Reentrant Hybrid Intravascular Stent

2018 ◽  
Vol 10 (10) ◽  
pp. 1850105 ◽  
Author(s):  
Xiao Li Ruan ◽  
Jie Jie Li ◽  
Xiao Ke Song ◽  
Hong Jian Zhou ◽  
Wei Xing Yuan ◽  
...  
Keyword(s):  
Large Scale ◽  
Mechanical Design ◽  
Experimental Tests ◽  
Building Blocks ◽  
Industrial Applications ◽  
Mechanical Effect ◽  
Parametric Models ◽  
Element Analysis ◽  
Specific Strength ◽  
Intravascular Stents

Chiral and reentrant metastructures with auxetic deformation abilities can serve as the building blocks in many industrial applications because of their light weight, high specific strength, energy absorption properties. In this paper, we report an innovative tubular-like structure by a combined mechanical effect of antichiral and reentrant. 2D antichiral-reentrant hybrid structures consisting of circular nodes and tangentially-connected ligaments are predesigned and fabricated using laser cutting technology with high-resolution. The elastic properties and auxeticity of the plane structure are analyzed and compared based on finite element analysis (FEA) and experimental results. For the first time, the antichiral-reentrant hybrid intravascular stents with the auxetic feature are proposed and parametric models are devised with good geometrical structure demonstrated. A series of large-scale stents are manufactured with stereolithography apparatus (SLA) additive manufacturing technique, and their mechanical behaviors are investigated in both experimental tests and FEA. As the selected antichiral-reentrant hybrid stents with tailored expansion ability are subjected to radial loading by the dilation of the balloon, stents undergo identifiable deformation mechanism due to the beam-like ligaments and circular node elements in the varied geometrical design, resulting in the distinct stress outcomes in plaque. It is also demonstrated that the antichiral-reentrant hybrid stents with tunable auxeticity possess robust mechanical properties through implantation inside the obstructed lesion.

scholarly journals Flat-Top Cylinder Indenter for Mechanical Characterization: A Report of Industrial Applications

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1742
Author(s):  
Roberto Montanari ◽  
Alessandra Varone
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Case Studies ◽  
Large Scale ◽  
Complex Geometry ◽  
Indentation Test ◽  
Experimental Tests ◽  
Industrial Applications ◽  
Heat Sinks ◽  
Deep Indentation

FIMEC (flat-top cylinder indenter for mechanical characterisation) is an instrumented indentation test employing a cylindrical punch. It has been used to determine the mechanical properties of metallic materials in several applications of industrial interest. This work briefly describes the technique and the theory of indentation with a flat-ended punch. The flat indentation of metals has been investigated through experimental tests, and an equation has been derived to calculate the yield stress from the experimental data in deep indentation. The approach is supported by many data on various metals and alloys. Some selected case studies are presented in the paper: (i) crank manufacturing through pin squeeze casting; (ii) the evaluation of the local mechanical properties in a carter of complex geometry; (iii) the qualification of Al billets for extrusion; (iv) stress–relaxation tests on CuCrZr heat sinks; (v) the characterization of thick W coatings on CuCrZr alloy; (vi) the measure of the local mechanical properties of the molten-zone (MZ) and the heat-affected zone (HAZ) in welded joints. The case studies demonstrate the great versatility of the FIMEC test which provides information not available by employing conventional experimental techniques such as tensile, bending, and hardness tests. On the basis of theoretical knowledge and large amount of experimental data, FIMEC has become a mature technique for application on a large scale in industrial practice.

scholarly journals Biocatalysis in the Swiss Manufacturing Environment

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1420
Author(s):  
Katrin Hecht ◽  
Hans-Peter Meyer ◽  
Roland Wohlgemuth ◽  
Rebecca Buller
Keyword(s):  
Large Scale ◽  
Success Factors ◽  
Building Blocks ◽  
Industrial Applications ◽  
Manufacturing Environment ◽  
Industrial Landscape ◽  
Societal Challenges ◽  
Relevant Role ◽  
Biocatalytic Process

Biocatalysis has undergone a remarkable transition in the last two decades, from being considered a niche technology to playing a much more relevant role in organic synthesis today. Advances in molecular biology and bioinformatics, and the decreasing costs for gene synthesis and sequencing contribute to the growing success of engineered biocatalysts in industrial applications. However, the incorporation of biocatalytic process steps in new or established manufacturing routes is not always straightforward. To realize the full synthetic potential of biocatalysis for the sustainable manufacture of chemical building blocks, it is therefore important to regularly analyze the success factors and existing hurdles for the implementation of enzymes in large scale small molecule synthesis. Building on our previous analysis of biocatalysis in the Swiss manufacturing environment, we present a follow-up study on how the industrial biocatalysis situation in Switzerland has evolved in the last four years. Considering the current industrial landscape, we record recent advances in biocatalysis in Switzerland as well as give suggestions where enzymatic transformations may be valuably employed to address some of the societal challenges we face today, particularly in the context of the current Coronavirus disease 2019 (COVID-19) pandemic.

Multi-Scale Approach towards Groningen Masonry and Induced Seismicity

2017 ◽  
Vol 747 ◽  
pp. 653-661 ◽  
Author(s):  
Jan G. Rots ◽  
Francesco Messali ◽  
Rita Esposito ◽  
Valentina Mariani ◽  
Samira Jafari
Keyword(s):  
Induced Seismicity ◽  
Large Scale ◽  
Numerical Models ◽  
Experimental Tests ◽  
Lessons Learned ◽  
Analytical Models ◽  
Structural Level ◽  
Building Stock ◽  
Element Analysis ◽  
Existing Building

In the last years, the induced seismicity in the northern part of the Netherlands has considerably increased. The existing building stock was not designed for seismic loading, and it is characterised by very slender walls, limited cooperation between walls and floors, and use of cavity walls. As a consequence, the validation of analytical and numerical models for the assessment of unreinforced masonry buildings and the characterisation of the masonry at both material and structural level have become of great importance. An extensive large-scale testing program was performed at the Delft University of Technology in 2015 to create benchmarks for the validation of the numerical and analytical models. The attention was mainly devoted to a terraced house typology, which was widely adopted for housing in the period 1960-1980, and focused on the characterisation of the typology at various levels: material, connection, component and assemblage level. The experimental tests at component and assemblage levels were also reproduced by nonlinear finite element analysis, validated and calibrated against the data available from the testing campaign at material level. In this paper, an overview description of performed experiments and numerical analyses is provided; specific devotion is given to the main outcomes of the campaign and to the lessons learned by the experimental evidences for improving the numerical models.

scholarly journals Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2760
Author(s):  
Ruiye Li ◽  
Peng Cheng ◽  
Hai Lan ◽  
Weili Li ◽  
David Gerada ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Large Scale ◽  
Synchronous Generator ◽  
Axial Direction ◽  
Scale Model ◽  
Element Analysis ◽  
Axial Temperature ◽  
Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

scholarly journals A New Approach of Soft Joint Based on a Cable-Driven Parallel Mechanism for Robotic Applications

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1468
Author(s):  
Luis Nagua ◽  
Carlos Relaño ◽  
Concepción A. Monje ◽  
Carlos Balaguer
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Experimental Tests ◽  
Humanoid Robots ◽  
Inverse Kinematic ◽  
Element Analysis ◽  
New Approach ◽  
Flexible Polymer ◽  
The Mathematical Model

A soft joint has been designed and modeled to perform as a robotic joint with 2 Degrees of Freedom (DOF) (inclination and orientation). The joint actuation is based on a Cable-Driven Parallel Mechanism (CDPM). To study its performance in more detail, a test platform has been developed using components that can be manufactured in a 3D printer using a flexible polymer. The mathematical model of the kinematics of the soft joint is developed, which includes a blocking mechanism and the morphology workspace. The model is validated using Finite Element Analysis (FEA) (CAD software). Experimental tests are performed to validate the inverse kinematic model and to show the potential use of the prototype in robotic platforms such as manipulators and humanoid robots.

scholarly journals Mechanical design and finite element analysis of live working robot for 10kV distribution power systems

2021 ◽  
Vol 183 ◽  
pp. 331-336
Author(s):  
Zhang Liming ◽  
He Yulong ◽  
Xu Shanjun ◽  
Zhang Tong ◽  
Guo Junlong ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Power Systems ◽  
Mechanical Design ◽  
Element Analysis

scholarly journals Time-resolved PIV measurements of a deflected submerged jet interacting with liquid-gas and liquid-liquid interfaces

2021 ◽  
Author(s):  
Stefan Puttinger ◽  
Mahdi Saeedipour
Keyword(s):  
Liquid Layer ◽  
Large Scale ◽  
Free Surface Flow ◽  
Industrial Applications ◽  
Liquid Pool ◽  
Surface Flow ◽  
Two Phase ◽  
Time Resolved ◽  
Submerged Jet ◽  
Major Interest

AbstractThis paper presents an experimental investigation on the interactions of a deflected submerged jet into a liquid pool with its above interface in the absence and presence of an additional lighter liquid. Whereas the former is a free surface flow, the latter mimics a situation of two stratified liquids where the liquid-liquid interface is disturbed by large-scale motions in the liquid pool. Such configurations are encountered in various industrial applications and, in most cases, it is of major interest to avoid the entrainment of droplets from the lighter liquid into the main flow. Therefore, it is important to understand the fluid dynamics in such configurations and to analyze the differences between the cases with and without the additional liquid layer. To study this problem, we applied time-resolved particle image velocimetry experiments with high spatial resolution. A detailed data analysis of a small layer beneath the interface shows that although the presence of an additional liquid layer stabilizes the oscillations of the submerged jet significantly, the amount of kinetic energy, enstrophy, and velocity fluctuations concentrated in the proximity of the interface is higher when the oil layer is present. In addition, we analyze the energy distribution across the eigenmodes of a proper orthogonal distribution and the distribution of strain and vortex dominated regions. As the main objective of this study, these high-resolution time-resolved experimental data provide a validation platform for the development of new models in the context of the volume of fluid-based large eddy simulation of turbulent two-phase flows.

scholarly journals Study on the High-Speed Milling Performance of High-Volume Fraction SiCp/Al Composites

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4143
Author(s):  
Youzheng Cui ◽  
Shenrou Gao ◽  
Fengjuan Wang ◽  
Qingming Hu ◽  
Cheng Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Volume Fraction ◽  
Simulation Analysis ◽  
Cutting Temperature ◽  
High Volume ◽  
Cutting Parameters ◽  
High Volume Fraction ◽  
High Wear Resistance ◽  
Element Analysis

Compared with other materials, high-volume fraction aluminum-based silicon carbide composites (hereinafter referred to as SiCp/Al) have many advantages, including high strength, small change in the expansion coefficient due to temperature, high wear resistance, high corrosion resistance, high fatigue resistance, low density, good dimensional stability, and thermal conductivity. SiCp/Al composites have been widely used in aerospace, ordnance, transportation service, precision instruments, and in many other fields. In this study, the ABAQUS/explicit large-scale finite element analysis platform was used to simulate the milling process of SiCp/Al composites. By changing the parameters of the tool angle, milling depth, and milling speed, the influence of these parameters on the cutting force, cutting temperature, cutting stress, and cutting chips was studied. Optimization of the parameters was based on the above change rules to obtain the best processing combination of parameters. Then, the causes of surface machining defects, such as deep pits, shallow pits, and bulges, were simulated and discussed. Finally, the best cutting parameters obtained through simulation analysis was the tool rake angle γ0 = 5°, tool clearance angle α0 = 5°, corner radius r = 0.4 mm, milling depth ap = 50 mm, and milling speed vc= 300 m/min. The optimal combination of milling parameters provides a theoretical basis for subsequent cutting.

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