Finite Element Analysis of the non Linear Behavior of a Multilayer Piezoelectric Actuator

2005 ◽  
Vol 881 ◽  
Author(s):  
M. Elhadrouz ◽  
T. Ben Zineb ◽  
E. Patoor
Keyword(s):  
Degrees Of Freedom ◽  
Constitutive Law ◽  
Element Analysis ◽  
Linear Behavior ◽  
Time Element ◽  
Non Linear ◽  
Multilayer Actuator ◽  
Element Type ◽  
Definition Of ◽  
The Right

AbstractA constitutive law for ferroelectric and ferroelastic piezoceramics is implemented in ABAQUS Standard using the subroutine user element. A linear solid element is defined: it is an eight-node hexahedron having the mechanical displacement components and the electric potential as degrees of freedom for each node. The element is formulated for static analysis and it needs the definition of the contribution of this element to the Jacobian (stiffness) and the definition of an array containing the contributions of this element to the right-hand-side vectors of the overall system of equations The subroutine is called for each element that is of a user-defined element type each time element calculations are required. As an example, the element is used for the simulation of a multilayer actuator made of piezoceramics. In this case, the piezoelectric equations are not valid since the electric loading induces non linear phenomena, which are captured through the constitutive law implemented in the user element.

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.

An XYZ Parallel Kinematic Flexure Mechanism With Geometrically Decoupled Degrees of Freedom

2011 ◽  
Author(s):  
Shorya Awtar ◽  
John Ustick ◽  
Shiladitya Sen
Keyword(s):  
Degrees Of Freedom ◽  
Element Analysis ◽  
Motion Direction ◽  
Form Analysis ◽  
Flexure Mechanism ◽  
Non Linear ◽  
Decoupled Motion ◽  
Motion Range ◽  
Parallel Kinematic ◽  
Cross Axis

We present the constraint-based design of a novel parallel kinematic flexure mechanism that provides highly decoupled motions along the three translational directions (X, Y, and Z) and high stiffness along the three rotational directions (θx, θy, and θz). The geometric decoupling ensures large motion range along each translational direction and enables integration with large-stroke ground-mounted linear actuators or generators, depending on the application. The proposed design, which is based on a systematic arrangement of multiple rigid stages and parallelogram flexure modules, is analyzed via non-linear finite element analysis. A proof-of-concept prototype of the flexure mechanism is fabricated to validate its large range and decoupled motion capability. The analyses as well as the hardware demonstrate an XYZ motion range of 10 mm × 10 mm × 10 mm. Over this motion range, the non-linear FEA predicts a cross-axis error of less than 3%, parasitic rotations less than 2 mrad, less than 4% lost motion, actuator isolation less than 1.5%, and no perceptible motion direction stiffness variation. Ongoing work includes non-linear closed-form analysis and experimental measurement of these error motion and stiffness characteristics.

scholarly journals Heat Engines of Extraordinary Efficiency and the General Principle of their Operation

2017 ◽  
Author(s):  
Remi Cornwall
Keyword(s):  
Kinetic Theory ◽  
Degrees Of Freedom ◽  
Classification Scheme ◽  
Chemical Potential ◽  
Information Theoretic ◽  
Heat Engines ◽  
Magnetic Remanence ◽  
Maxwell Demon ◽  
Definition Of ◽  
The Right

The intention of this paper is to elucidate new types of heat engines with extraordinary efficiency, more specifically to eventually focus on the author’s research into a temporary magnetic remanence device. First we extend the definition of heat engines through a diagrammatic classification scheme and note a paradoxical non-coincidence between the Carnot, Kelvin-Planck and other forms of the 2nd Law, between sectors of the diagram. It is then seen, between the diagram sectors, how super-efficient heat engines are able to reduce the degrees of freedom resulting from change in chemical potential, over mere generation of heat; until in the right sector of the diagram, the conventional wisdom for the need of two reservoirs is refuted. A brief survey of the Maxwell Demon problem finds no problem with information theoretic constructs. Our ongoing experimental enquiry into a temporary magnetic remanence cycle using standard kinetic theory, thermodynamics and electrodynamics is presented – yet a contradiction results with the 2nd law placing it in the right sector of the classification diagram.

A Multi-Level Approach for the Numerical Modelling of Complex Monumental Buildings

2015 ◽  
pp. 546-575
Author(s):  
Siro Casolo ◽  
Andrea Fiore ◽  
Francesco Porco ◽  
Domenico Raffaele ◽  
Carlo Alberto Sanjust ◽  
...  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Numerical Models ◽  
3D Finite Element ◽  
Computational Approaches ◽  
Linear Behavior ◽  
Significant Damage ◽  
Non Linear ◽  
Multi Level

Monumental buildings are characterized by elements (such as columns, vaults, arches …) that can suffer significant damage even under moderate earthquakes. Unfortunately, the available modeling approaches require a huge amount of computing resources. The chapter presents a multi-level strategy that is able to overcome these difficulties by a rational adoption of different computational approaches. As a case study, the non-linear seismic assessment of the medieval “Maniace Castle”, in Syracuse (Sicily, Italy) is developed, by using different numerical models. First, the linear behavior of the building is studied by means of two 3D Finite Element models. Then, results are used to calibrate a 2D plane Rigid Body and Spring Model (RBSM), specifically formulated for approximating the macroscopic behavior of masonry texture with a small number of degrees of freedom. In order to account for the variability of the material characteristics, parametric non-linear analyses have been performed and compared.

Understanding the Effects of Soil Characteristics on Mobility

2017 ◽  
Author(s):  
Paramsothy Jayakumar ◽  
Dave Mechergui ◽  
Tamer M. Wasfy
Keyword(s):  
Particle Size ◽  
Soft Soil ◽  
Soil Characteristics ◽  
Vehicle Speed ◽  
Soil Density ◽  
Ground Vehicles ◽  
Wheel Slip ◽  
Linear Behavior ◽  
Non Linear ◽  
The Right

The Army’s mission is to develop, integrate, and sustain the right technology solutions for all manned and unmanned ground vehicles, and mobility is a key requirement for all ground vehicles. Mobility focuses on ground vehicles’ capabilities that enable them to be deployable worldwide, operationally mobile in all environments, and protected from symmetrical and asymmetrical threats. In order for military ground vehicles to operate in any combat zone, mobility on off-road terrains should be extensively investigated. Mobility on off-road terrains is poorly understood because of the empirical and semi-empirical methods used in predicting the mobility map. These methods do not capture the soil deformation as well as its non-linear behavior. The discrete element method (DEM) was identified as a high-fidelity method that can capture the deformation of the soil and its non-linear behavior. The DEM method allows to simulate the vehicle on any off-road terrain and to generate an accurate mobility map. In this paper, a simulation study was undertaken to understand the influence of soil characteristics on mobility parameters such as wheel sinkage, wheel slip, vehicle speed, and tractive force. The interaction of the vehicle wheels with soft soil is poorly understood, this study helps understand this interaction. A nominal wheeled vehicle model was built in the DIS/IVRESS software and simulated over different cohesive and non-cohesive soils modeled using DEM. Some characteristics of these soils were varied namely, the soil inter-particle cohesion, the soil inter-particle friction, the soil particle size, and the soil density. The mobility parameters were measured and correlated to the soil characteristics. This study showed that the vehicle speed increased with cohesion, friction, soil density, and particle size, while wheel sinkage and wheel slip decreased with those parameters. The influence of these characteristics combined is more complex; extensive studies of other soil characteristics need to be carried out in the future to understand their effect on vehicle mobility.

scholarly journals Tie Rod-Equivalent Non-Linear Constitutive Law for Uniformly Loaded Cables

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5502
Author(s):  
Pietro Croce
Keyword(s):  
Virtual Work ◽  
Electrical Power ◽  
Constitutive Law ◽  
Suspension Bridges ◽  
General Validity ◽  
Simplified Approach ◽  
Closed Form Solutions ◽  
Linear Behavior ◽  
Non Linear ◽  
Main Cables

Cables are typically used in engineering applications as tensile members. Relevant examples are the main cables of suspension bridges, the stays of cable-stayed bridges, the load-bearing and stabilizing cables of tensile structures, the anchor cables of floating mooring structures, the guy-ropes for ship masts, towers, and wind turbines, the copper cables of electrical power lines. Since cables are characterized by non-linear behavior, analysis of cable structures often requires advanced techniques, like non-linear FEM, able to consider geometric non-linearity. Nevertheless, a traditional simplified approach consists in replacing the cable with an equivalent tie rod, characterized by a suitable non-linear constitutive law. Currently used equivalent constitutive laws have been derived by Dischinger, Ernst and Irvine. Since the equivalence is restricted to taut cables, characterized by small sag to chord ratios, these traditional formulae are not appropriate for uniformly loaded sagging cables: the main cables of suspension bridges are a particularly emblematic case. Despite some recent attempts to find more refined solutions, the problem is still open, since closed form solutions of general validity are not available. In the paper, general analytical formulae of the non-linear constitutive law of the equivalent tie rod are proposed, distinguishing two relevant cases, according as the length of the cable can vary or not. The expressions, derived by applying the general form of the theorem of virtual work, can be applied independently on the material, on the sag to chord ratio, on the load intensity and on the stress level, so allowing the replacement of the whole cable with a single equivalent tie rod. The expressions are critically discussed referring to a wide parametric study also in comparison with the existing formulae, stressing the influence of the most relevant parameters.

scholarly journals A Multi-Level Approach for the Numerical Modelling of Complex Monumental Buildings

2016 ◽  
pp. 1352-1378
Author(s):  
Siro Casolo ◽  
Andrea Fiore ◽  
Francesco Porco ◽  
Domenico Raffaele ◽  
Carlo Alberto Sanjust ◽  
...  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Numerical Models ◽  
3D Finite Element ◽  
Computational Approaches ◽  
Linear Behavior ◽  
Significant Damage ◽  
Non Linear ◽  
Multi Level

Monumental buildings are characterized by elements (such as columns, vaults, arches …) that can suffer significant damage even under moderate earthquakes. Unfortunately, the available modeling approaches require a huge amount of computing resources. The chapter presents a multi-level strategy that is able to overcome these difficulties by a rational adoption of different computational approaches. As a case study, the non-linear seismic assessment of the medieval “Maniace Castle”, in Syracuse (Sicily, Italy) is developed, by using different numerical models. First, the linear behavior of the building is studied by means of two 3D Finite Element models. Then, results are used to calibrate a 2D plane Rigid Body and Spring Model (RBSM), specifically formulated for approximating the macroscopic behavior of masonry texture with a small number of degrees of freedom. In order to account for the variability of the material characteristics, parametric non-linear analyses have been performed and compared.

THE CONCEPT OF CONSTITUTIONAL AND LEGAL GUARANTEES OF ELECTORAL RIGHTS

2020 ◽  
Vol 10 (4) ◽  
pp. 85-90
Author(s):  
VLADIMIR TROYAN ◽  
Keyword(s):  
Scientific Research ◽  
Formal Aspect ◽  
Universal Approach ◽  
Right To Vote ◽  
Definition Of ◽  
The Right

The relevance of the interpretation of constitutional and legal guarantees of the right to vote is mediated by isolated scientific research in this area, as well as the lack of a universal approach to legal guarantees. In this regard, the purpose of the article is to argue and disclose the author’s definitive aspect of the claimed guarantees. In the work, the author named and characterized the normative (based exclusively on legal means) with the perspective of a branch of legal and technical; regulatory and institutional (combines the formal aspect with the activities of authorized entities) and associated legal (including a set of legal and other aspects) approaches to the definition of legal guarantees. Based on the second approach, as well as combining the guarantees of the right to vote directly guarantees of the subjective right itself and guarantees of its implementation, the author offers a definition of constitutional and legal guarantees of the right to vote.

A two degrees of freedom comb capacitive-type accelerometer with low cross-axis sensitivity

2019 ◽  
Vol 13 (3) ◽  
pp. 5334-5346
Author(s):  
M. N. Nguyen ◽  
L. Q. Nguyen ◽  
H. M. Chu ◽  
H. N. Vu
Keyword(s):  
Degrees Of Freedom ◽  
Proof Mass ◽  
Vibration Modes ◽  
Electrode Structure ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Fully Differential ◽  
Mode Effects ◽  
The Finite Element Analysis ◽  
Cross Axis

In this paper, we report on a SOI-based comb capacitive-type accelerometer that senses acceleration in two lateral directions. The structure of the accelerometer was designed using a proof mass connected by four folded-beam springs, which are compliant to inertial displacement causing by attached acceleration in the two lateral directions. At the same time, the folded-beam springs enabled to suppress cross-talk causing by mechanical coupling from parasitic vibration modes. The differential capacitor sense structure was employed to eliminate common mode effects. The design of gap between comb fingers was also analyzed to find an optimally sensing comb electrode structure. The design of the accelerometer was carried out using the finite element analysis. The fabrication of the device was based on SOI-micromachining. The characteristics of the accelerometer have been investigated by a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit. The sensitivities of the accelerometer in the two lateral directions were determined to be 6 and 5.5 fF/g, respectively. The cross-axis sensitivities of the accelerometer were less than 5%, which shows that the accelerometer can be used for measuring precisely acceleration in the two lateral directions. The accelerometer operates linearly in the range of investigated acceleration from 0 to 4g. The proposed accelerometer is expected for low-g applications.

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