Dynamics and vibrations of structures with bonded piezoelectric strips subjected to mechanical and unsteady aerodynamic loads

2010 ◽  
Vol 225 (3) ◽  
pp. 625-638 ◽  
Author(s):  
D Mateescu ◽  
Y Han ◽  
A Misra
Keyword(s):  
Dynamic Analysis ◽  
Crack Detection ◽  
Piezoelectric Actuators ◽  
Element Formulation ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Wing Structures ◽  
Piezoelectric Strip ◽  
Wing Structure ◽  
The Time Domain

This article presents an analysis of the dynamics of damaged structures with bonded piezoelectric strips executing flexural oscillations generated by mechanical loads, piezoelectric actuators or unsteady aerodynamic loads. These oscillations can be used to detect the presence of cracks for structural health monitoring. The proposed method of crack detection uses pairs of piezoelectric strip sensors bonded on the opposite sides of the structure and is based on the fact that the presence of a crack causes a difference between the strains measured by the two sensors of a pair. The structural analysis presented in this article uses a non-linear model for the cracks and a finite-element formulation for the piezoelectric strips coupled with the structure. A panel method is used to determine the unsteady aerodynamic loads acting on the oscillating wing structure. This study includes the dynamic analysis in the frequency domain of a cracked plate undergoing forced flexural vibrations in a range of frequencies generated by a pair of piezoelectric actuators. The dynamic analysis in the time domain is also performed for the oscillating structures with piezoelectric strips subjected to mechanical or unsteady aerodynamic loads. It was found that this method is quite effective in detecting cracks in the wing structures subjected to oscillatory aerodynamic loads.

Analysis of the Dynamics and Vibrations of Structures Subjected to Unsteady Aerodynamic Loads for Crack Detection

2009 ◽  
Vol 417-418 ◽  
pp. 605-608
Author(s):  
Dan Mateescu ◽  
Yong Han ◽  
Arun Misra
Keyword(s):  
Crack Detection ◽  
Strain Sensors ◽  
Element Formulation ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Detection Strategy ◽  
Nonlinear Mechanical ◽  
Wing Structures ◽  
Wing Structure ◽  
Oscillatory Cycle

This paper is devoted to the analysis of the dynamics and vibrations of wing-like structures with bonded piezoelectric strips and subjected to unsteady aerodynamic loads for crack detection. Pairs of piezoelectric strips, acting as strain sensors, are bonded at the same locations on the opposite sides of a thin structure executing flexural oscillations. In this crack detection strategy, the measured voltage outputs of the two piezoelectric sensors forming a pair are conveniently subtracted in order to eliminate the voltage corresponding to the same level of strain on both sides. This differential voltage output is used to indicate the presence of a crack in the structure. The nonlinear mechanical behavior of the crack in the compression and extension phases of the oscillatory cycle increases substantially the sensitivity of this detection procedure. Furthermore, this crack detection method can take advantage of the aeroelastic oscillations of the wing structures, which are always present during normal flight evolutions of an aircraft. The numerical analysis of the dynamics of structure subjected to unsteady aerodynamic loads uses a finite element formulation for the structure and the piezoelectric strips and a panel method is used to compute the unsteady aerodynamic loads acting on the oscillating wing structure. Numerical simulation results are presented in the paper to explore the feasibility of this crack detection strategy by using the aeroelastic oscillations of the wing-like structures with bonded piezoelectric strips.

Study of Aerospace Structures With Bonded Piezoelectric Strips Subjected to Unsteady Aerodynamic Loads for Structural Health Monitoring

2012 ◽  
Author(s):  
Yong Han ◽  
Dan Mateescu ◽  
Arun K. Misra
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Crack Detection ◽  
Early Stage ◽  
Angle Of Attack ◽  
Piezoelectric Actuators ◽  
Piezoelectric Sensors ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Wing Structure

This paper studies the aeroelastic oscillations of wing-like structures with the aim to detect at an incipient stage the presence of structural cracks. Such oscillations occur normally in certain flight evolutions of aircraft or can be excited by piezoelectric actuators bonded on the wing structure. These oscillations can be used to detect at an early stage the presence of cracks by monitoring the response of several piezoelectric sensors bonded on both sides of the structure during the aeroelastic oscillations. The proposed method of crack detection uses pairs of piezoelectric strip sensors bonded on the opposite sides of the structure and is based on the fact that the presence of a crack causes a difference between the strains measured by the two sensors of a pair. The structural analysis presented in this paper uses a nonlinear model for the cracks and a finite element formulation for the piezoelectric strips coupled with the structure. A 3D panel method developed by the authors is used to determine the unsteady aerodynamic loads acting on the oscillating wing structure. The dynamic analysis in the time domain is performed for the oscillating structures with piezoelectric strips subjected to unsteady aerodynamic loads. In the present work, the efficiency of this crack detection method is studied in realistic situations, by considering the aeroelastic oscillations in flexion and torsion of a wing-like structure which are excited in one of the following modes: (i) the aeroelastic oscillations excited by a pair of piezoelectric actuators bonded on the opposite sides of the structure; (ii) the aeroelastic oscillations excited by the harmonic oscillation of the angle of attack corresponding to the flight in atmospheric turbulence (harmonic gust); (iii) the aeroelastic oscillations generated by a sudden change in the angle of attack or in the airplane velocity due to a pilot control input. The numerical simulations for these cases have been performed by the simultaneous solution of the coupled equations of unsteady fluid flow and of the structure deformation motion, by using a finite element method for the dynamic of the structures with cracks and bonded piezoelectric strips, and a 3D panel method developed by the authors for the calculation of the unsteady aerodynamic loads. These numerical simulations have shown that the presence of a crack in the structure can be efficiently detected at an early stage by monitoring the response of the pairs of piezoelectric sensors.

Dynamics of Structures with Piezoelectric Sensors and Actuators for Structural Health Monitoring

2007 ◽  
Vol 347 ◽  
pp. 493-498 ◽  
Author(s):  
Dan Mateescu ◽  
Yong Han ◽  
Arun Misra
Keyword(s):  
Dynamic Analysis ◽  
Crack Detection ◽  
Piezoelectric Sensors ◽  
Element Formulation ◽  
Sensors And Actuators ◽  
Cracked Plates ◽  
Piezoelectric Sensors And Actuators ◽  
Differential Voltage ◽  
Thin Structure ◽  
The Time Domain

The dynamic analysis of structures with piezoelectric sensors and actuators is used in this paper to establish a method for crack detection in aerospace structures. Piezoelectric strips used as sensors and actuators are bonded on both sides of a thin structure which executes flexural oscillations. The differential voltage outputs of the piezoelectric sensors are used to detect the presence of cracks in the structure. The structural analysis uses a finite element formulation for the piezoelectric strips coupled with the structure and a nonlinear model for the cracks. This paper presents first the results of the dynamic analysis in the frequency domain of healthy and cracked plates undergoing forced flexural vibrations generated by a pair of piezoelectric actuators submitted to an oscillatory voltage excitation. The peaks in the differential voltage output obtained in the case of a cracked plate at several frequencies during the frequency sweep were found to be indicative measures for the presence of a crack in the structure. The results of the dynamic analysis in the time domain have also shown that this method has a good sensitivity in detecting cracks in the structures.

Aerolelastic Analysis of a Thin-Walled Composite Aircraft Wing With an External Store Subjected to a Follower Force

2014 ◽  
Author(s):  
Alev Kacar Aksongur ◽  
Seher Eken ◽  
Metin O. Kaya
Keyword(s):  
Transverse Shear ◽  
Structural Model ◽  
Follower Force ◽  
Beam Model ◽  
Aircraft Wing ◽  
Sweep Angle ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Thin Walled ◽  
The Time Domain

This study reports dynamic aeroelastic analyses of an aircraft wing with an attached mass subjected a lateral follower force in an incompressible flow. A swept thin-walled composite beam with a biconvex cross-section is used as the structural model that incorporates a number of non-classical effects such as material anisotropy, transverse shear deformation and warping restraint. A symmetric lay-up configuration i.e. circumferentially asymmetric stiffness (CAS) is further adapted to this model to generate the coupled motion of flapwise bending-torsion-transverse shear. For this beam model, the unsteady aerodynamic loads are expressed using Wagners function in the time-domain as well as using Theodorsen function in the frequency-domain. The flutter speeds are evaluated for several ply angles and the effects of follower force, transverse shear, fiber-orientation and sweep angle on the aeroelastic instabilities are further discussed.

scholarly journals Time and Frequency Domain Dynamic Analysis of Offshore Mooring

2021 ◽  
Vol 9 (7) ◽  
pp. 781
Author(s):  
Shi He ◽  
Aijun Wang
Keyword(s):  
Dynamic Analysis ◽  
Frequency Domain ◽  
Time Domain ◽  
Linearization Method ◽  
Euler Method ◽  
Single Component ◽  
Hydrodynamic Drag ◽  
Lumped Mass ◽  
Mooring Lines ◽  
The Time Domain

The numerical procedures for dynamic analysis of mooring lines in the time domain and frequency domain were developed in this work. The lumped mass method was used to model the mooring lines. In the time domain dynamic analysis, the modified Euler method was used to solve the motion equation of mooring lines. The dynamic analyses of mooring lines under horizontal, vertical, and combined harmonic excitations were carried out. The cases of single-component and multicomponent mooring lines under these excitations were studied, respectively. The case considering the seabed contact was also included. The program was validated by comparing with the results from commercial software, Orcaflex. For the frequency domain dynamic analysis, an improved frame invariant stochastic linearization method was applied to the nonlinear hydrodynamic drag term. The cases of single-component and multicomponent mooring lines were studied. The comparison of results shows that frequency domain results agree well with nonlinear time domain results.

Theory of a Time Domain Boundary Element Development for the Dynamic Analysis of Coupled Multiphase Porous Media

2017 ◽  
Vol 08 (03n04) ◽  
pp. 1750007
Author(s):  
Pooneh Maghoul ◽  
Behrouz Gatmiri
Keyword(s):  
Boundary Element ◽  
Time Domain ◽  
Unsaturated Soils ◽  
Water Pressure ◽  
Domain Boundary ◽  
Fundamental Solutions ◽  
Element Formulation ◽  
Inertia Effects ◽  
Coupled Equations ◽  
The Time Domain

This paper presents an advanced formulation of the time-domain two-dimensional (2D) boundary element method (BEM) for an elastic, homogeneous unsaturated soil subjected to dynamic loadings. Unlike the usual time-domain BEM, the present formulation applies a convolution quadrature which requires only the Laplace-domain instead of the time-domain fundamental solutions. The coupled equations governing the dynamic behavior of unsaturated soils ignoring contributions of the inertia effects of the fluids (water and air) are derived based on the poromechanics theory within the framework of a suction-based mathematical model. In this formulation, the solid skeleton displacements [Formula: see text], water pressure [Formula: see text] and air pressure [Formula: see text] are presumed to be independent variables. The fundamental solutions in Laplace transformed-domain for such a dynamic [Formula: see text] theory have been obtained previously by authors. Then, the BE formulation in time is derived after regularization by partial integrations and time and spatial discretizations. Thereafter, the BE formulation is implemented in a 2D boundary element code (PORO-BEM) for the numerical solution. To verify the accuracy of this implementation, the displacement response obtained by the boundary element formulation is verified by comparison with the elastodynamics problem.

Experimental Validation of a Dynamic Simulation

1990 ◽  
Author(s):  
K. Harold Yae ◽  
Su-Tai Chern ◽  
Howyoung Hwang
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Time Domain ◽  
Experimental Validation ◽  
Initial Conditions ◽  
Hydraulic Cylinder ◽  
Force Output ◽  
Inverse Dynamic ◽  
Inverse Dynamic Analysis ◽  
The Time Domain

Abstract Using forward and inverse dynamic analysis, the dynamic simulation of a backhoe has been compared with experiments. In the experiment, recorded were the configuration and force histories; that is, velocity and position, and force output from the hydraulic cylinder-all were measured in the time domain. When the experimental force history is used as driving force in the simulation, forward dynamic analysis produces a corresponding motion history. And when the experimental motion history is used as if a prescribed trajectory, inverse dynamic analysis generates a corresponding force history. Therefore, these two sets of motion and force histories — one set from experiment, and the other from the simulation that is driven forward and backward with the experimental data — are compared in the time domain. The comparisons are discussed in regard to the effects of variations in initial conditions, friction, and viscous damping.

Full-scale tests of unsteady aerodynamic loads and pressure distribution on fast trains in crosswinds

Measurement ◽  
2021 ◽  
Vol 186 ◽  
pp. 110152
Author(s):  
Hongrui Gao ◽  
Tanghong Liu ◽  
Houyu Gu ◽  
Zhiwei Jiang ◽  
Xiaoshuai Huo ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Full Scale ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Full Scale Tests

Selection of the Optimal Structural Design of a Spar Composite Wing

2021 ◽  
pp. 90-99
Author(s):  
O.V. Tatarnikov ◽  
W.A. Phyo ◽  
Lin Aung Naing
Keyword(s):  
Optimal Design ◽  
Element Analysis ◽  
Minimal Weight ◽  
Wing Structures ◽  
Optimization Parameters ◽  
Nonlinear Static ◽  
Wing Structure ◽  
Pareto Method ◽  
Selection Of ◽  
Composite Wing

This paper describes a method for optimizing the design of a spar-type composite aircraft wing structure based on multi-criterion approach. Two types of composite wing structures such as two-spar and three-spar ones were considered. The optimal design of a wing frame was determined by the Pareto method basing on three criteria: minimal weight, minimal wing deflection, maximal safety factor and minimal weight. Positions of wing frame parts, i.e. spars and ribs, were considered as optimization parameters. As a result, an optimal design of a composite spar-type wing was proposed. All the calculations necessary to select the optimal structural and design of the spar composite wing were performed using nonlinear static finite element analysis in the FEMAP with NX Nastran software package.

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