Development and validation of a non-linear k-ε model for flow over a full-scale building

2001 ◽  
Vol 4 (3) ◽  
pp. 177-196 ◽  
Author(s):  
N.G. Wright ◽  
G.J. Easom ◽  
R.J. Hoxey
Keyword(s):  
Full Scale ◽  
Non Linear ◽  
Development And Validation

Paper 16. Measurement of Steering Derivatives on Full-Scale Ship Trials

1972 ◽  
Vol 14 (7) ◽  
pp. 115-122
Author(s):  
G. R. G. Lewison
Keyword(s):  
Drift Velocity ◽  
Full Scale ◽  
Small Vessel ◽  
Numerical Example ◽  
Non Linear

The track of a ship executing manoeuvres may be recorded relative to a floating buoy and analysed to give speed and drift velocity. A new oscillating turn manoeuvre is described. The results of this, together with turning circles and pull-outs, may be used to calculate six linear and two non-linear derivatives in the equations of sway and yaw. A numerical example is given, based upon full-scale trials on a small vessel.

Viscoelastic Behavior of Carbon Nanotube Yarns and Twisted Coils

2018 ◽  
Author(s):  
Pouria Khanbolouki ◽  
Mehran Tehrani
Keyword(s):  
Carbon Nanotube ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Energy Harvesters ◽  
Linear Behavior ◽  
Non Linear ◽  
Stretchable Conductors ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Development And Validation

Coiled structures made from polymer and Carbon Nanotube (CNT) yarns are used as artificial muscles, stretchable conductors, and energy harvesters. The purpose of this work is to present our latest understanding of the mechanical behavior of these CNT-based structures. CNT yarns are fabricated by inserting twists in sheets spun from CNT forests. Over twisting the CNT yarns results in coiled CNT yarns, similar to a spring where the spring radius is comparable to the diameter of the CNT yarn. In this study, we explain the development and validation of a viscoelastic model, to capture damping and hysteresis in CNT yarns under quasi-static and dynamic loads. Confirmation of linear viscoelastic behavior of CNT yarns can lead us to the development of a model for coiled CNT yarns. Coiled CNT yarns, on the other hand, show a complex non-linear viscoelastic behavior. Possible mechanisms responsible for this non-linear behavior are discussed.

Development and Validation of a Non-Linear Viscoelastic Viscoplastic Stress Model for a PFCB/PVDF Fuel Cell Membrane

2012 ◽  
Author(s):  
Jessica A. Wright ◽  
Michael W. Ellis ◽  
David A. Dillard ◽  
Scott W. Case ◽  
Robert B. Moore ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Numerical Models ◽  
Proton Exchange ◽  
Mechanical Degradation ◽  
Stress Model ◽  
Uniaxial Creep ◽  
Non Linear ◽  
Viscoelastic Modulus ◽  
Linear Viscoelastic ◽  
Development And Validation

Proton exchange membranes (PEMs) in operating fuel cells are subjected to varying thermal and hygral loads while under mechanical constraint imposed within the compressed stack. Swelling during hygrothermal cycles can result in residual in-plane tensile stresses in the membrane and lead to mechanical degradation or failure through thinning or pinhole development. Numerical models can predict the stresses resulting from applied loads based on material characteristics, thus helping to guide the development of more durable membrane materials. In this work, a non-linear viscoelastic stress model based on the Schapery constitutive formulation is used with a Zapas-Crissman viscoplastic term to describe the response of a novel membrane material comprised of a blend of perfluorocyclobutane (PFCB) ionomer and polyvinylidene fluoride (PVDF). Uniaxial creep and recovery tests are used to establish the time dependent linear viscoelastic modulus as well as the fitting parameters for the non-linear viscoelastic viscoplastic model. The stress model is implemented in a commercial finite element code, Abaqus®, to predict the response of a membrane subjected to mechanical loads. The stress model is validated by comparing predicted and experimental responses for membranes subjected to stress relaxation and multiple step creep loads in uniaxial tension.

Development and validation of multi-axis substructure testing system for full-scale experiments

2015 ◽  
Vol 16 (4) ◽  
pp. 302-315 ◽  
Author(s):  
M. Javad Hashemi ◽  
Riadh Al-Mahaidi ◽  
Robin Kalfat ◽  
Graeme Burnett
Keyword(s):  
Full Scale ◽  
Testing System ◽  
Development And Validation

Paper 15. Some Aspects of Prediction and Simulation of Manoeuvres

1972 ◽  
Vol 14 (7) ◽  
pp. 108-114
Author(s):  
G. van Leeuwen
Keyword(s):  
Mathematical Models ◽  
Linear Models ◽  
Empirical Models ◽  
Model Tests ◽  
Full Scale ◽  
Non Linear ◽  
Free Running ◽  
Horizontal Oscillation ◽  
Prediction And Simulation

Prediction and simulation are dependent on the knowledge gained from mathematical models. The choice and the form of the model is determined by the specific application and the accuracy required. Model techniques, such as horizontal oscillation tests, provide the means of finding the coefficients of extensive non-linear models, though for other purposes, such as simulation, there is also a need for simpler, empirical models. To determine the coefficients of such models, free-running full-scale or model tests are necessary.

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