An elastic phenomenological material law of technical textile with a nonlinear shear behaviour

2021 ◽  
pp. 073168442110058
Author(s):  
Dániel T Karádi ◽  
András A Sipos ◽  
Marianna Halász ◽  
Viktor Hliva ◽  
Dezső Hegyi
Keyword(s):  
Service Level ◽  
Shear Behaviour ◽  
Nonlinear Behaviour ◽  
Exponential Functions ◽  
Normal Stiffness ◽  
Material Parameters ◽  
Fitting Method ◽  
Highly Nonlinear ◽  
Nonlinear Shear ◽  
Magnitude Difference

In technical textile engineering, macro-level phenomenological modelling effectively describes the material’s highly nonlinear behaviour. However, existing material laws concentrate on the normal stiffness in the orthotropic yarns and simplify the shear effect because of the two orders of magnitude difference between shear and normal stiffness. This article introduces an improved phenomenological model that includes nonlinear shear behaviour, and it determines the material parameters with a previously applied data fitting method for exponential functions. The nonlinear shear behaviour is valid for the elastic state, that is, at the service level of the loads. Time-dependent, cyclic loading or plastic behaviour is not considered.

scholarly journals Design analysis of four-wave-mixing in SiN nanowires integrated with graphene oxide films

2020 ◽  
Author(s):  
David Moss
Keyword(s):  
Graphene Oxide ◽  
Kerr Nonlinearity ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Trade Off ◽  
Material Parameters ◽  
Highly Nonlinear ◽  
Thermal Changes ◽  
Strong Mode ◽  
Good Agreement

<p>We theoretically investigate and optimize four-wave mixing (FWM) in silicon nitride (SiN) waveguides integrated with two-dimensional (2D) layered graphene oxide (GO) films. Based on extensive previous measurements of the material parameters of the GO films, we perform detailed analysis for the influence of device parameters including waveguide geometry, GO film thickness, length, and coating position on the FWM conversion efficiency (CE) and conversion bandwidth (CB). The influence of dispersion and photo-thermal changes in the GO films is also discussed. Owing to the strong mode overlap between the SiN waveguides and the highly nonlinear GO films, FWM in the hybrid waveguides can be significantly enhanced. We obtain good agreement with previous experimental results and show that by optimizing the device parameters to balance the trade-off between Kerr nonlinearity and loss, the FWM CE can be improved by as much as ~20.7 dB and the FWM CB can be increased by ~4.4 folds, relative to the uncoated waveguides. These results highlight the significantly enhanced FWM performance that can be achieved in SiN waveguides by integrating 2D layered GO films.<i></i></p>

Simulation and Experimental Study in Position Control of Servo Hydraulic System With Flexible Load Using Adaptive Neural Network and Differential Evolution Strategy

2006 ◽  
Author(s):  
Hassan Yousefi ◽  
Heikki Handroos
Keyword(s):  
Neural Network ◽  
Differential Evolution ◽  
Position Control ◽  
Differential Evolution Algorithm ◽  
System Stability ◽  
Minimum Problem ◽  
Nonlinear Behaviour ◽  
Neural Network Controller ◽  
Highly Nonlinear ◽  
Flexible Load

Hydraulic position servos with an asymmetrical cylinder are commonly used in industry. These kinds of systems are nonlinear in nature and generally difficult to control. Because of parameters changing during extending and retracting, using constant gain will cause overshoot, poor performance or even loss of system stability. The highly nonlinear behaviour of these devices makes them ideal subjects for applying different types of sophisticated controllers. This paper is concerned with a second order adaptive model reference and an artificial neural network controller to position tracking of a servo hydraulic with a flexible load. In present study, a neural network with two outputs is presented. One of the outputs of neural network is used for system’s dynamic compensator and another one for gain scheduling controller. To avoid the local minimum problem, Differential Evolution Algorithm (DEA) is used to find the weights and biases of neural network. The proposed controller is verified with a common used p-controller. The simulation and experimental results suggest that if the neural network is chosen and trained well, it improves all performance evaluation criteria such as stability, fast response, and accurate reference model tracking in servo hydraulic systems.

scholarly journals A double-layer Boussinesq-type model for highly nonlinear and dispersive waves

2009 ◽  
Vol 465 (2108) ◽  
pp. 2319-2346 ◽  
Author(s):  
F. Chazel ◽  
M. Benoit ◽  
A. Ern ◽  
S. Piperno
Keyword(s):  
Double Layer ◽  
Deep Water ◽  
Type Model ◽  
Nonlinear Behaviour ◽  
Approximate Inverse ◽  
Dispersive Waves ◽  
Final Model ◽  
Water Value ◽  
Highly Nonlinear ◽  
Model Derivation

We derive and analyse, in the framework of the mild-slope approximation, a new double-layer Boussinesq-type model that is linearly and nonlinearly accurate up to deep water. Assuming the flow to be irrotational, we formulate the problem in terms of the velocity potential, thereby lowering the number of unknowns. The model derivation combines two approaches, namely the method proposed by Agnon et al. ( Agnon et al. 1999 J. Fluid Mech. 399 , 319–333) and enhanced by Madsen et al. ( Madsen et al. 2003 Proc. R. Soc. Lond. A 459 , 1075–1104), which consists of constructing infinite-series Taylor solutions to the Laplace equation, to truncate them at a finite order and to use Padé approximants, and the double-layer approach of Lynett & Liu ( Lynett & Liu 2004 a Proc. R. Soc. Lond. A 460 , 2637–2669), which allows lowering the order of derivatives. We formulate the model in terms of a static Dirichlet–Neumann operator translated from the free surface to the still-water level, and we derive an approximate inverse of this operator that can be built once and for all. The final model consists of only four equations both in one and two horizontal dimensions, and includes only second-order derivatives, which is a major improvement in comparison with so-called high-order Boussinesq models. A linear analysis of the model is performed, and its properties are optimized using a free parameter determining the position of the interface between the two layers. Excellent dispersion and shoaling properties are obtained, allowing the model to be applied up to the deep-water value k h =10. Finally, numerical simulations are performed to quantify the nonlinear behaviour of the model, and the results exhibit a nonlinear range of validity reaching at least k h =3π.

scholarly journals Exponential Polynomial Fitting for Fibre Spectrum CCD Profiles

2010 ◽  
Vol 27 (3) ◽  
pp. 290-295 ◽  
Author(s):  
Zhangqin Zhu ◽  
Jia Zhu ◽  
Hanqin Qin ◽  
Chong Wang ◽  
Zhongfu Ye
Keyword(s):  
Least Squares ◽  
Spatial Orientation ◽  
Least Squares Method ◽  
Exponential Polynomial ◽  
Exponential Functions ◽  
Polynomial Fitting ◽  
Gaussian Functions ◽  
Profile Fitting ◽  
Fitting Method

AbstractA fibre spectrum profile fitting method based on the least-squares method is presented in this article. For each spectrum of one fibre in spatial orientation, two exponential functions are employed to approximate the profile. Experiments are performed with both simulated profiles and observed profiles to demonstrate the effectiveness of the algorithm. Specially, the proposed method has a better performance for profiles that are asymmetric or composed of multi-Gaussian functions.

Determination of Material Parameters for Nonlinear Analysis of Reinforced Concrete

2017 ◽  
Vol 738 ◽  
pp. 140-150
Author(s):  
Jan Kubosek ◽  
Jana Vaskova
Keyword(s):  
Tensile Strength ◽  
Nonlinear Analysis ◽  
Unknown Input ◽  
Nonlinear Behaviour ◽  
Material Parameters ◽  
Model Code ◽  
Input Parameters ◽  
Loading Case ◽  
Compressive Strength Of Concrete

The aim of the paper is a nonlinear analysis of concrete structures. For these type of tasks is an important suitable choice of model input parameters and concrete. Especially if the analysis is preceding the results of an experiment, which can determine the exact properties of concrete. The following properties of concrete are needed for nonlinear analysis: tensile strength and compressive strength of concrete. There are more procedures how to determine some unknown input parameters. The paper presents some approaches to calculating and selecting parameters, which are based primarily on the recommendations of the Model Code and professional articles. Specifically, the numerical analysis performed in our developed program which allows observing a nonlinear behaviour of concrete at loading case.

Design analysis of four-wave-mixing in SiN nanowires integrated with graphene oxide films

2020 ◽  
Author(s):  
David Moss
Keyword(s):  
Graphene Oxide ◽  
Kerr Nonlinearity ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Trade Off ◽  
Material Parameters ◽  
Highly Nonlinear ◽  
Thermal Changes ◽  
Strong Mode ◽  
Good Agreement

<p>We theoretically investigate and optimize four-wave mixing (FWM) in silicon nitride (SiN) waveguides integrated with two-dimensional (2D) layered graphene oxide (GO) films. Based on extensive previous measurements of the material parameters of the GO films, we perform detailed analysis for the influence of device parameters including waveguide geometry, GO film thickness, length, and coating position on the FWM conversion efficiency (CE) and conversion bandwidth (CB). The influence of dispersion and photo-thermal changes in the GO films is also discussed. Owing to the strong mode overlap between the SiN waveguides and the highly nonlinear GO films, FWM in the hybrid waveguides can be significantly enhanced. We obtain good agreement with previous experimental results and show that by optimizing the device parameters to balance the trade-off between Kerr nonlinearity and loss, the FWM CE can be improved by as much as ~20.7 dB and the FWM CB can be increased by ~4.4 folds, relative to the uncoated waveguides. These results highlight the significantly enhanced FWM performance that can be achieved in SiN waveguides by integrating 2D layered GO films.<i></i></p>

Sign in / Sign up

Export Citation Format

Share Document