Search results for "numerical [Methods]"
showing 10 items of 500 documents
Electromechanical behavior of carbon nanotubes under traction, bending, torsion and misalignment of the two ends
2011
Carbon nanotubes (CNTs) can be metallic or semiconductors depending simply on geometric characteristics [e.g., 1]. This peculiar electronic behavior, combined with high mechanical strength, make them potential building blocks of a new nano-electronic technology. Most discussions of the electronic structure of CNTs assume perfect cylindrical symmetry, but this is somewhat of an oversimplification. High resolution images of CNTs often disclose structural deformations such as bent, twisted, or collapsed tubes. These deformations may develop during growth, deposition, and processing, or upon interaction with other CNTs, and with surfaces and surface features such as electrodes. Deformations bre…
PROPAGAZIONE DI ONDE DI RAYLEIGH LUNGO SUPERFICI CURVE: UNO STUDIO NUMERICO E SPERIMENTALE
2014
Il fenomeno della propagazione delle onde di superficie lungo confini rettilinei (superfici piane) è stato studiato adeguatamente. Tuttavia le indagini riguardanti la loro propagazione in superfici cilindriche sono limitate e risultano insufficienti ai fini di un loro utilizzo nelle tecniche d’ispezione non distruttive (NDE), nonostante possano essere di grande interesse per svariate applicazioni. E’ stato dimostrato sperimentalmente che l’onda superficiale subisce un cambiamento di fase durante la sua propagazione lungo una superficie cilindrica. Un approccio numerico è stato sviluppato per studiare questi effetti per diversi materiali, curvature e frequenze. I risultati numerici e sperime…
Experimental and numerical method for nondestructive ultrasonic defect detection
2010
Ultrasonic methods are well known as powerful and reliable tool for defect detection. Conventional ultrasonic techniques rely generally on piezoelectric transducers where transmission of energy to the material is achieved with contact. In the last decades focus and interest have been directed to non-contact sensors and methods, showing many advantages over contact techniques where inspection depends on contact conditions (pressure, coupling medium, contact area). The growing interest is also due to the further development of air-coupled probes, thanks to new materials for acoustic devices and manufacturing technologies. The use of laser as tool for ultrasonic defect detection is also an eme…
Mixed Numerical-Analytical Model for Predicting the Elastic Properties of Nanocomposites with Random Distribution of CNTs
2009
Analysis of the Parameters Affecting the Stiffness of Short Sisal Fiber Biocomposites Manufactured by Compression-Molding
2021
The use of natural fiber-based composites is on the rise in many industries. Thanks to their eco-sustainability, these innovative materials make it possible to adapt the production of components, systems and machines to the increasingly stringent regulations on environmental protection, while at the same time reducing production costs, weight and operating costs. Optimizing the mechanical properties of biocomposites is an important goal of applied research. In this work, using a new numerical approach, the effects of the volume fraction, average length, distribution of orientation and curvature of fibers on the Young’s modulus of a biocomposite reinforced with short natural fibers were stud…
Reinforcing effect of carbon nanotubes (CNT) on polymer nanocomposites – A numerical-analytical study
2012
A mixed model, numerical-analytical, is presented that allows one to predict the elastic properties of carbon nanotube (CNT)/polymer composites containing a random distribution of CNTs, while taking account of the curvature that they show when immersed in the polymer. This hybrid approach is a significant advance over micromechanical modeling and can be applied to all nanostructured composites.
Numerical model for the electromechanical characterization of carbon nanotubes
2010
Carbon nanotubes (CNTs) can be metallic or semiconductors depending simply on geometric characteristics [e.g., 1]. This peculiar electronic behavior, combined with high mechanical strength, make them potential building blocks of a new nano-electronic technology. Most discussions of the electronic structure of CNTs assume perfect cylindrical symmetry, but this is somewhat of an oversimplification. High resolution images of CNTs often disclose structural deformations such as bent, twisted, or collapsed tubes. These deformations may develop during growth, deposition, and processing, or upon interaction with other CNTs, and with surfaces and surface features such as electrodes. Deformations bre…
A mixed finite element-tight binding technique for studying the electromechanical behavior of single and multiwall carbon nanotubes
2004
Fluid-structure interaction and flow redistribution in membrane-bounded channels
2019
The hydrodynamics of electrodialysis and reverse electrodialysis is commonly studied by neglecting membrane deformation caused by transmembrane pressure (TMP). However, large frictional pressure drops and differences in fluid velocity or physical properties in adjacent channels may lead to significant TMP values. In previous works, we conducted one-way coupled structural-CFD simulations at the scale of one periodic unit of a profiled membrane/channel assembly and computed its deformation and frictional characteristics as functions of TMP. In this work, a novel fluid&ndash
Investigation of heat transfer in spacer-filled channels by experiments and direct numerical simulations
2016
Abstract The analysis of flow fields and heat or mass transfer phenomena is of great importance in the optimum design of spacer-filled channel geometries for a variety of membrane-based processes. In the present work, models of spacer-filled channels often adopted in Membrane Distillation are simultaneously investigated by experiments and Computational Fluid Dynamics (CFD). Experiments rely on a non-intrusive technique, based on the use of Thermochromic Liquid Crystals (TLC) and digital image processing, and provide the local distribution of the convective heat transfer coefficient on a thermally active wall. CFD relies on steady-state (laminar flow) simulations in the lower end of the Reyn…