Analysis of the Non-Linear Behavior of ECLIPSE Actuators

Aerospace ◽  
2005 ◽  
Author(s):  
Kyle G. Webber ◽  
Christopher S. Lynch
Keyword(s):  
Residual Stress ◽  
Lead Zirconate Titanate ◽  
Epoxy Composite ◽  
Plane Deformation ◽  
Stress Gradient ◽  
Curing Temperature ◽  
Classical Lamination Theory ◽  
Linear Behavior ◽  
Non Linear ◽  
Lamination Theory

This work discusses the development and characterization of rectangular shaped Epoxy Composite Laminated Piezoelectric Stress-Enhanced actuators (ECLIPSE). ECLIPSE actuators are unimorph type d31 actuators that are manufactured with a lead zirconate titanate (PZT) plate sandwiched between unidirectional Kevlar 49/epoxy composite layers with dissimilar coefficients of thermal expansion in orthogonal directions. Cooling the actuator from an elevated curing temperature resulted in a residual stress gradient through the actuator, a compressive stress on the brittle piezoelectric plate, and a large out-of-plane deformation. Extended classical lamination theory (ECLT) is used to model the residual stress state and curvature of the actuator. The model results are compared to the classical lamination theory. The ECLT was developed by Hyer to explain the non-linear behavior of unsymmetric cross-ply laminates [1-3]. Three actuator layups were fabricated and characterized: [90/PZT/90/0], [90/90/PZT/90/0/0], and [90/90/90/PZT/90/0/0/0]. It is shown that geometric non-linearity is important to consider when modeling ECLIPSE actuators.

Thermally Induced Twist in Graphite-Epoxy Tubes

1988 ◽  
Vol 110 (2) ◽  
pp. 83-88 ◽  
Author(s):  
M. W. Hyer ◽  
C. Q. Rousseau ◽  
S. S. Tompkins
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Plane Deformation ◽  
Radial Position ◽  
Elasticity Analysis ◽  
Thermally Induced ◽  
Classical Lamination Theory ◽  
Experimental Apparatus ◽  
Lamination Theory

This paper discusses an analytical and experimental study to investigate the thermally induced twist in laminated angle-ply graphite-epoxy tubes. Attention is focused on balanced laminates which, contrary to intuition, exhibit twist when the temperature is changed. The twisting is due to the fact that in tube a lamina with a + Φ orientation and a lamina with a − Φ orientation must be at slightly different radial positions. The lamina with the greater radial position determines the sense of the twist. Classical lamination theory does not predict this phenomenon and so a more sophisticated theory must be employed. This paper outlines such a theory, which is based on a generalized plane deformation elasticity analysis, and presents experimental data to confirm the predictions of the theory. A brief description of the experimental apparatus and procedure used to measure twist is presented.

Out-of-plane deformation and pull-in voltage of cantilevers with residual stress gradient: experiment and modelling

2018 ◽  
Vol 25 (9) ◽  
pp. 3581-3588 ◽  
Author(s):  
Anna Persano ◽  
Jacopo Iannacci ◽  
Pietro Siciliano ◽  
Fabio Quaranta
Keyword(s):  
Residual Stress ◽  
Plane Deformation ◽  
Stress Gradient ◽  
Out Of Plane ◽  
Residual Stress Gradient

The Influence of Stress Gradient on X-ray Stress Measurement

1994 ◽  
Vol 38 ◽  
pp. 463-470
Author(s):  
Masaaki Ohtsuka ◽  
Hideaki Matsuoka ◽  
Yukio Hirose ◽  
Hitoshi Ishii
Keyword(s):  
Stress Measurement ◽  
Stress Gradient ◽  
Measurement Data ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Linear Behavior ◽  
Non Linear ◽  
Machine Parts ◽  
Fine Ceramics

The various machine parts made of fine ceramics are usually finished by grinding. The X-ray elastic constants in ground ceramics are measured by the X-ray diffraction method, as a result a measurement error can occur. The cause of the error is the stress gradient in the material produced by the grinding. In the case of material in which a stress gradient is present, X-ray stress measurement data show non-linear 2θφψ- sin2 ψ diagrams. Until now, the X-ray stress measurement by the sin2ψ method makes use of effectively linear 2θφψ - sin2 ψ diagrams. In the case of 2θφψ - sin2 ψ diagrams showing non-linear behavior, however, good analysis method are generally not available.

Measurement of X-Ray Elastic Constants From Ground Ceramic Showing Non-Linear Sin2ϕ Diagrams

1993 ◽  
Vol 37 ◽  
pp. 305-315 ◽  
Author(s):  
Masaaki Ohtsuka ◽  
Hideaki Matsuoka ◽  
Yukio Hirose ◽  
Hitoshi Ishii
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Ray Method ◽  
X Ray ◽  
The Past ◽  
Linear Behavior ◽  
Non Linear ◽  
Machined Parts ◽  
Stress Measuring ◽  
Fine Ceramics

Machined parts made of fine ceramics are usually finished by grinding (Yajima et al.,1990, Mishima et al.,1987). The residual stress introduced by grinding will influence the fracture strength and the function of ceramics, and needs further consideration. Over the past few years, a considerable number of studies have evaluated ground ceramics by means of the X-ray method. However, it is well known that X-ray stress measuring data, 2 θ φ φ-sin2 φ curves of the surface layer of the unidirectionally machined ceramics are showing non-linear behavior (Kishimoto et al.,1987) . In this case, the sin2 φ method is inadequate for the evaluation of the stress (Sasaki et al.,1989).

Nonlinear Time Series Analysis with R

2018 ◽  
Author(s):  
Ray Huffaker ◽  
Marco Bittelli ◽  
Rodolfo Rosa
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Particle Physics ◽  
Linear Time ◽  
Nonlinear Time Series ◽  
Nonlinear Time Series Analysis ◽  
Series Analysis ◽  
Linear Behavior ◽  
Non Linear ◽  
Scientific Principles

In the process of data analysis, the investigator is often facing highly-volatile and random-appearing observed data. A vast body of literature shows that the assumption of underlying stochastic processes was not necessarily representing the nature of the processes under investigation and, when other tools were used, deterministic features emerged. Non Linear Time Series Analysis (NLTS) allows researchers to test whether observed volatility conceals systematic non linear behavior, and to rigorously characterize governing dynamics. Behavioral patterns detected by non linear time series analysis, along with scientific principles and other expert information, guide the specification of mechanistic models that serve to explain real-world behavior rather than merely reproducing it. Often there is a misconception regarding the complexity of the level of mathematics needed to understand and utilize the tools of NLTS (for instance Chaos theory). However, mathematics used in NLTS is much simpler than many other subjects of science, such as mathematical topology, relativity or particle physics. For this reason, the tools of NLTS have been confined and utilized mostly in the fields of mathematics and physics. However, many natural phenomena investigated I many fields have been revealing deterministic non linear structures. In this book we aim at presenting the theory and the empirical of NLTS to a broader audience, to make this very powerful area of science available to many scientific areas. This book targets students and professionals in physics, engineering, biology, agriculture, economy and social sciences as a textbook in Nonlinear Time Series Analysis (NLTS) using the R computer language.

Behaviour of Axially Loaded Composite Wall Panel by Using Finite Element Analysis

2015 ◽  
Vol 815 ◽  
pp. 49-53
Author(s):  
Nur Fitriah Isa ◽  
Mohd Zulham Affandi Mohd Zahid ◽  
Liyana Ahmad Sofri ◽  
Norrazman Zaiha Zainol ◽  
Muhammad Azizi Azizan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Element Analysis ◽  
Steel Sheets ◽  
Linear Behavior ◽  
Non Linear ◽  
Composite Wall ◽  
Experimental Values ◽  
Civil Engineering Infrastructure

In order to promote the efficient use of composite materials in civil engineering infrastructure, effort is being directed at the development of design criteria for composite structures. Insofar as design with regard to behavior is concerned, it is well known that a key step is to investigate the influence of geometric differences on the non-linear behavior of the panels. One possible approach is to use the validated numerical model based on the non-linear finite element analysis (FEA). The validation of the composite panel’s element using Trim-deck and Span-deck steel sheets under axial load shows that the present results have very good agreement with experimental references. The developed finite element (FE) models are found to reasonably simulate load-displacement response, stress condition, giving percentage of differences below than 15% compared to the experimental values. Trim-deck design provides better axial resistance than Span-deck. More concrete in between due to larger area of contact is the factor that contributes to its resistance.

Mitigating the Effects of Non-Linear Distortion Using Polarizers in Microwave Photonic Link

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarika Singh ◽  
Sandeep K. Arya ◽  
Shelly Singla
Keyword(s):  
Dynamic Range ◽  
Extinction Ratio ◽  
Polarization Angle ◽  
Third Order ◽  
Microwave Photonic ◽  
Linear Behavior ◽  
Spurious Free Dynamic Range ◽  
Non Linear ◽  
Intermodulation Distortions ◽  
Insertion Losses

AbstractA scheme to suppress nonlinear intermodulation distortion in microwave photonic (MWP) link is proposed by using polarizers to compensate inherent non-linear behavior of dual-electrode Mach-Zehnder modulator (DE-MZM). Insertion losses and extinction ratio have also been considered. Simulation results depict that spurious free dynamic range (SFDR) of proposed link reaches to 130.743 dB.Hz2/3. A suppression of 41 dB in third order intermodulation distortions and an improvement of 15.3 dB is reported when compared with the conventional link. In addition, an electrical spectrum at different polarization angles is extracted and 79^\circ is found to be optimum value of polarization angle.

scholarly journals Early Detection of Defects through the Identification of Distortion Characteristics in Ultrasonic Responses

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 850
Author(s):  
Pietro Burrascano ◽  
Matteo Ciuffetti
Keyword(s):  
Early Detection ◽  
Additive Noise ◽  
Linear Models ◽  
High Stress ◽  
Damage Index ◽  
Hammerstein Model ◽  
Linear Behavior ◽  
Non Linear ◽  
Ultrasonic Techniques ◽  
Detection Of Defects

Ultrasonic techniques are widely used for the detection of defects in solid structures. They are mainly based on estimating the impulse response of the system and most often refer to linear models. High-stress conditions of the structures may reveal non-linear aspects of their behavior caused by even small defects due to ageing or previous severe loading: consequently, models suitable to identify the existence of a non-linear input-output characteristic of the system allow to improve the sensitivity of the detection procedure, making it possible to observe the onset of fatigue-induced cracks and/or defects by highlighting the early stages of their formation. This paper starts from an analysis of the characteristics of a damage index that has proved effective for the early detection of defects based on their non-linear behavior: it is based on the Hammerstein model of the non-linear physical system. The availability of this mathematical model makes it possible to derive from it a number of different global parameters, all of which are suitable for highlighting the onset of defects in the structure under examination, but whose characteristics can be very different from each other. In this work, an original damage index based on the same Hammerstein model is proposed. We report the results of several experiments showing that our proposed damage index has a much higher sensitivity even for small defects. Moreover, extensive tests conducted in the presence of different levels of additive noise show that the new proposed estimator adds to this sensitivity feature a better estimation stability in the presence of additive noise.

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