The effect of residual stress on the non-linear behaviour of composite laminates Part II. Layer, laminate non-linear models and the effect of residual stress on the model parameters

2001 ◽  
Vol 61 (2) ◽  
pp. 177-190 ◽  
Author(s):  
D. Perreux ◽  
D. Lazuardi
Keyword(s):  
Residual Stress ◽  
Composite Laminates ◽  
Linear Models ◽  
Model Parameters ◽  
Non Linear ◽  
Linear Behaviour

Output feedback stabilization of hydraulic drives based on bilinear approximations and canonical observers

1998 ◽  
Vol 212 (2) ◽  
pp. 79-85 ◽  
Author(s):  
H Schwarz
Keyword(s):  
Output Feedback ◽  
Linear Models ◽  
Feedback Stabilization ◽  
Bilinear Models ◽  
Control Scheme ◽  
Non Linear ◽  
Linear Behaviour ◽  
Operating Points ◽  
Complete Operation ◽  
Model Approach

This paper deals with the control of hydrostatic drives on the basis of bilinear models. It is shown that by using bilinear models a considerably better approximation of the non-linear behaviour of hydraulic drives can be achieved compared with common linear models. The bilinear model approach gives rise to control results valid not only for fixed operating points but also for the complete operation range of the drives. In particular, an output feedback using a canonical observer and quadratic state feedback is proposed. A separation theorem for this non-linear control scheme similar to that for linear systems is proved, i.e. the dynamics of the observer and of the controlled plant are adjustable separately.

Modelling the non-linear behaviour of the pot bearings of railway bridge KW51

2021 ◽  
Author(s):  
Menno Van De Velde ◽  
Kristof Maes ◽  
Geert Lombaert
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Model Parameters ◽  
Railway Bridge ◽  
Digital Twin ◽  
Linear Finite Element ◽  
Non Linear ◽  
First Results ◽  
Linear Behaviour

<p>Railway bridge KW51 in Leuven, Belgium, has been monitored since October 2018 with the aim of constructing a digital twin, i.e. a virtual representation that mimics the behaviour of the actual struc- ture. A linear finite element model of the bridge was updated using measurements carried out on the bridge. The pot bearings of the bridge, however, are found to behave in a non-linear way. This paper describes a methodology to account for this non-linear behaviour in the model, where friction in the bearings is accounted for by means of non-linear Bouc-Wen elements. The first results are presented, showing that the overall non-linear behaviour of the bearings during a train passage is well captured but that further research is needed to calibrate the model parameters.</p>

scholarly journals Non-linear investigation of an asymmetric disk brake model

2011 ◽  
Vol 225 (10) ◽  
pp. 2325-2332 ◽  
Author(s):  
G Spelsberg-Korspeter ◽  
D Hochlenert ◽  
P Hagedorn
Keyword(s):  
Linear Models ◽  
Equations Of Motion ◽  
Symmetric Case ◽  
Point Of View ◽  
Disk Brake ◽  
Design Engineers ◽  
Brake Rotor ◽  
Non Linear ◽  
Linear Behaviour ◽  
Insight Into

Among design engineers, it is known that breaking symmetries of a brake rotor can help to prevent squeal. From a modelling point of view, in the literature brake squeal is almost exclusively treated using models with a symmetric brake rotor, which are capable of explaining the excitation mechanism but yield no insight into the relation between rotor asymmetry and stability. In previous work, it has been demonstrated with linear models that the breaking of symmetries of the brake rotor has a stabilizing effect. The equations of motion for this case have periodic coefficients with respect to time and are therefore more difficult to analyse than in the symmetric case. The goal of this article is to investigate whether due to the breaking of symmetries also, the non-linear behaviour of the brake changes qualitatively compared to the symmetric case.

G Optimal Design in Non linear Models to Increase Silicon Oxide Purity Levels and Electrical Conductivity

2018 ◽  
pp. 150-155
Author(s):  
Muklas Rivai
Keyword(s):  
Electrical Conductivity ◽  
Optimal Design ◽  
Linear Models ◽  
Silicon Oxide ◽  
Information Matrix ◽  
Relevant Information ◽  
Non Linear

Optimal design is a design which required in determining the points of variable factors that would be attempted to optimize the relevant information so that fulfilled the desired criteria. The optimal fulfillment criteria based on the information matrix of the selected model.

Adaptive control of time-varying non-linear plants by speed-gradient algorithms

2019 ◽  
pp. 37-44 ◽  
Author(s):  
O. P. Tomchina ◽  
D. N. Polyakhov ◽  
O. I. Tokareva ◽  
A. L. Fradkov
Keyword(s):  
Adaptive Control ◽  
Adaptive Systems ◽  
Reference Model ◽  
Maximum Deviation ◽  
Model Parameters ◽  
Time Varying ◽  
System Solution ◽  
Non Linear ◽  
Initial Uncertainty ◽  
Speed Gradient

Introduction: The motion of many real world systems is described by essentially non-linear and non-stationary models. A number of approaches to the control of such plants are based on constructing an internal model of non-stationarity. However, the non-stationarity model parameters can vary widely, leading to more errors. It is only assumed in this paper that the change rate of the object parameters is limited, while the initial uncertainty can be quite large.Purpose: Analysis of adaptive control algorithms for non-linear and time-varying systems with an explicit reference model, synthesized by the speed gradient method.Results: An estimate was obtained for the maximum deviation of a closed-loop system solution from the reference model solution. It is shown that with sufficiently slow changes in the parameters and a small initial uncertainty, the limit error in the system can be made arbitrarily small. Systems designed by the direct approach and systems based on the identification approach are both considered. The procedures for the synthesis of an adaptive regulator and analysis of the synthesized system are illustrated by an example.Practical relevance: The obtained results allow us to build and analyze a broad class of adaptive systems with reference models under non-stationary conditions.

Nearly Exact Bayesian Estimation of Non-linear No-Arbitrage Term-Structure Models*

2021 ◽  
Author(s):  
Marcello Pericoli ◽  
Marco Taboga
Keyword(s):  
Bayesian Estimation ◽  
Term Structure ◽  
Broad Class ◽  
Model Parameters ◽  
State Variables ◽  
Computationally Efficient ◽  
Macroeconomic Factors ◽  
No Arbitrage ◽  
Term Structure Models ◽  
Non Linear

Abstract We propose a general method for the Bayesian estimation of a very broad class of non-linear no-arbitrage term-structure models. The main innovation we introduce is a computationally efficient method, based on deep learning techniques, for approximating no-arbitrage model-implied bond yields to any desired degree of accuracy. Once the pricing function is approximated, the posterior distribution of model parameters and unobservable state variables can be estimated by standard Markov Chain Monte Carlo methods. As an illustrative example, we apply the proposed techniques to the estimation of a shadow-rate model with a time-varying lower bound and unspanned macroeconomic factors.

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