scholarly journals Quantitative measures and 3D shell models reveal interactions between bands and their position on growing snail shells

2021 ◽  
Author(s):  
Hannah J. Jackson ◽  
Jenny Larsson ◽  
Angus Davison
Keyword(s):  
Shell Models

Influence of fasteners and connections flexibility on deflections of steel building including the stressed skin effect

2018 ◽  
Vol 2 (21) ◽  
pp. 131-148 ◽  
Author(s):  
Natalia Korcz ◽  
Elżbieta Urbańska-Galewska
Keyword(s):  
Finite Elements ◽  
Skin Effect ◽  
Numerical Models ◽  
Orthotropic Shell ◽  
3D Structure ◽  
Negligible Effect ◽  
Transverse Stiffness ◽  
Shell Models ◽  
Steel Building ◽  
Two Sides

The paper presents the analysis of the influence of fasteners and connections flexibility on displacements of symmetrical single-bay pitched-roof steel building, including trapezoidal cladding acting as a diaphragm. The purpose of the article was to compare numerical models with and without taking into consideration fasteners and connections flexibility in order to observe the differences in transverse stiffness of the building during modifying model from the simple one to more complex and precise. The analyses were carried out for the 3D structure. Fasteners and connections were substituted by equivalent beam finite elements. Corrugated sheets were replaced by three types of equivalent orthotropic shell models and the influence of the choice of the model on the stiffness of the building was observed. The results showed that in the analysed structure the flexibility of fasteners and connections has negligible effect on transverse displacements of the building in the case of four sides fastening of the sheeting, however in the case of two sides fastening the influence significantly increases.

Multiple particle tracking

2018 ◽  
Author(s):  
Eric M. Furst ◽  
Todd M. Squires
Keyword(s):  
Brownian Motion ◽  
Best Practices ◽  
Particle Tracking ◽  
Heterogeneous Material ◽  
Quantitative Measurements ◽  
Particle Tracking Microrheology ◽  
Shell Models ◽  
Multiple Particle Tracking ◽  
Microscopy Data ◽  
Multiple Particle

The fundamentals and best practices of multiple particle tracking microrheology are discussed, including methods for producing video microscopy data, analyzing data to obtain mean-squared displacements and displacement correlations, and, critically, the accuracy and errors (static and dynamic) associated with particle tracking. Applications presented include two-point microrheology, methods for characterizing heterogeneous material rheology, and shell models of local (non-continuum) heterogeneity. Particle tracking has a long history. The earliest descriptions of Brownian motion relied on precise observations, and later quantitative measurements, using light microscopy.

scholarly journals Ergodicity of Stochastic Shell Models Driven by Pure Jump Noise

2016 ◽  
Vol 48 (2) ◽  
pp. 1423-1458 ◽  
Author(s):  
Hakima Bessaih ◽  
Erika Hausenblas ◽  
Paul A. Razafimandimby
Keyword(s):  
Shell Models ◽  
Jump Noise

scholarly journals Exact periodic solutions of shell models of turbulence

Nonlinearity ◽  
2007 ◽  
Vol 20 (10) ◽  
pp. 2333-2352
Author(s):  
Poul Olesen ◽  
Mogens H Jensen
Keyword(s):  
Periodic Solutions ◽  
Shell Models ◽  
Shell Models Of Turbulence

Vibronic Spectra and the Shell Models

1969 ◽  
Vol 185 (3) ◽  
pp. 1163-1167 ◽  
Author(s):  
W. E. Bron
Keyword(s):  
Vibronic Spectra ◽  
Shell Models

Some new results and current challenges in the finite element analysis of shells

Acta Numerica ◽  
2001 ◽  
Vol 10 ◽  
pp. 215-250 ◽  
Author(s):  
Dominique Chapelle
Keyword(s):  
Finite Element ◽  
Shell Theory ◽  
Shell Structures ◽  
Engineering Practice ◽  
Element Analysis ◽  
Shell Elements ◽  
Shell Models ◽  
The Finite Element Analysis ◽  
Shell Finite Element ◽  
Mathematical Analyses

This article, a companion to the article by Philippe G. Ciarlet on the mathematical modelling of shells also in this issue of Acta Numerica, focuses on numerical issues raised by the analysis of shells.Finite element procedures are widely used in engineering practice to analyse the behaviour of shell structures. However, the concept of ‘shell finite element’ is still somewhat fuzzy, as it may correspond to very different ideas and techniques in various actual implementations. In particular, a significant distinction can be made between shell elements that are obtained via the discretization of shell models, and shell elements – such as the general shell elements – derived from 3D formulations using some kinematic assumptions, without the use of any shell theory. Our first objective in this paper is to give a unified perspective of these two families of shell elements. This is expected to be very useful as it paves the way for further thorough mathematical analyses of shell elements. A particularly important motivation for this is the understanding and treatment of the deficiencies associated with the analysis of thin shells (among which is the locking phenomenon). We then survey these deficiencies, in the framework of the asymptotic behaviour of shell models. We conclude the article by giving some detailed guidelines to numerically assess the performance of shell finite elements when faced with these pathological phenomena, which is essential for the design of improved procedures.

Analytical higher-order-theories for noise reduction analysis of viscoelastic composite multilayered shells

2021 ◽  
pp. 095440622098233
Author(s):  
A Alaimo ◽  
C Orlando ◽  
S Valvano
Keyword(s):  
Sound Transmission ◽  
Higher Order ◽  
Sound Insulation ◽  
Viscoelastic Layer ◽  
Multilayered Structures ◽  
Viscoelastic Composite ◽  
Damping Behavior ◽  
Shell Models ◽  
Composite Layers ◽  
Insulation Effect

The noise transmission of aeronautical panels is an important phase of the design process of an airplane. In this work an analytical Navier-type solution, based on higher-order layer-wise shell models, is proposed for the analysis of the sound insulation of laminated panels. The considered multilayered structures are laminated with cross-ply composite layers embedded with interlaminar viscoelastic sheets. The use of the soft interlayers permits to have a passive insulation effect in the study of the sound transmission. In order to take into account the frequency depedent properties of a realistic viscoelastic layer, the damping behavior is modeled through a fractional derivative Zener model. The Rayleigh integral method is used to extrapolate the acoustic indicators for the sound transmission analysis. Some results are presented to validate the efficiency of the present approach, comparing the present solutions with others taken from the literature.

Relativistic shell models and meson-exchange currents

1987 ◽  
Vol 475 (4) ◽  
pp. 720-742 ◽  
Author(s):  
J. Delorme ◽  
I.S. Towner
Keyword(s):  
Meson Exchange ◽  
Shell Models ◽  
Meson Exchange Currents
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