Free vibration of three-dimensional multilayered magneto-electro-elastic plates under combined clamped/free boundary conditions

2014 ◽  
Vol 333 (17) ◽  
pp. 4017-4029 ◽  
Author(s):  
J.Y. Chen ◽  
P.R. Heyliger ◽  
E. Pan
Keyword(s):  
Free Boundary ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Elastic Plates ◽  
Free Boundary Conditions

Modelling the three-dimensional vibration of composite archery arrows under free–free boundary conditions

2012 ◽  
Vol 226 (2) ◽  
pp. 114-122
Author(s):  
Marianne Rieckmann ◽  
James L Park ◽  
John Codrington ◽  
Ben Cazzolato
Keyword(s):  
Free Boundary ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Laser Doppler Vibrometer ◽  
Theoretical Models ◽  
Free Boundary Conditions ◽  
Scanning Laser Doppler Vibrometer ◽  
Resonance Frequencies ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Archery performance has been shown to be dependent on the resonance frequencies and operational deflection shape of the arrows. This vibrational behaviour is influenced by the design and material of the arrow and the presence of damage in the arrow structure. In recent years arrow design has progressed to use lightweight and stiff composite materials. This paper investigates the vibration of composite archery arrows through a finite difference model based on Euler–Bernoulli theory, and a three-dimensional finite element modal analysis. Results from the numerical simulations are compared to experimental measurements using a Polytec scanning laser Doppler vibrometer (PSV-400). The experiments use an acoustically coupled vibration actuator to excite the composite arrow with free–free boundary conditions. Evaluation of the vibrational behaviour shows good agreement between the theoretical models and the experiments.

A Composite Sandwich Structure With Embedded MEMS-Based Vibration Sensing

1999 ◽  
Author(s):  
Kishore Pochiraju
Keyword(s):  
Free Boundary ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Sandwich Beam ◽  
Shear Deformation Theory ◽  
Vibration Response ◽  
Vibration Monitoring ◽  
Sandwich Composite ◽  
Free Boundary Conditions ◽  
Free Vibration Response

Abstract This paper presents a sandwich composite architecture suitable for embedding MEMS-based accelerometers for long-term vibration monitoring or to act as sensors in adaptive structures. The presented architecture is designed around multi-axis accelerometers and temperature sensors that are commercially available. These devices also integrate sophisticated sensor compensation and data acquisition hardware into a single integrated circuit chip package. The paper presents the stiffness modeling of a sandwich composite with embedded accelerometers based on classical lamination theory. The first order shear deformation theory is used to compute the free vibration response of the sandwich composite. Solutions are presented for the free-vibration response of the sandwich beam under fixed-free boundary conditions. Results presented also include the response obtained from the MEMS-accelerometer when coupled to a thick cross-ply laminate under fixed-free boundary conditions.

scholarly journals Local Well-Posedness for Free Boundary Problem of Viscous Incompressible Magnetohydrodynamics

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 461
Author(s):  
Kenta Oishi ◽  
Yoshihiro Shibata
Keyword(s):  
Free Surface ◽  
Free Boundary ◽  
Boundary Conditions ◽  
Stokes Equations ◽  
Mhd Flow ◽  
Transmission Conditions ◽  
Well Posedness ◽  
Anisotropic Space ◽  
Free Boundary Conditions ◽  
Incompressible Magnetohydrodynamics

In this paper, we consider the motion of incompressible magnetohydrodynamics (MHD) with resistivity in a domain bounded by a free surface. An electromagnetic field generated by some currents in an external domain keeps an MHD flow in a bounded domain. On the free surface, free boundary conditions for MHD flow and transmission conditions for electromagnetic fields are imposed. We proved the local well-posedness in the general setting of domains from a mathematical point of view. The solutions are obtained in an anisotropic space Hp1((0,T),Hq1)∩Lp((0,T),Hq3) for the velocity field and in an anisotropic space Hp1((0,T),Lq)∩Lp((0,T),Hq2) for the magnetic fields with 2<p<∞, N<q<∞ and 2/p+N/q<1. To prove our main result, we used the Lp-Lq maximal regularity theorem for the Stokes equations with free boundary conditions and for the magnetic field equations with transmission conditions, which have been obtained by Frolova and the second author.

scholarly journals Identification of Corrosion on a Hollow Tube Using Vibration

2014 ◽  
Vol 564 ◽  
pp. 176-181
Author(s):  
S.T. Cheng ◽  
Nawal Aswan Abdul Jalil ◽  
Zamir A. Zulkefli
Keyword(s):  
Free Boundary ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Impact Loading ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Localized Corrosion ◽  
Free Boundary Conditions ◽  
The Impact ◽  
Impact Vibration

Vibration based technique have so far been focused on the identification of structural damage. However, not many studies have been conducted on the corrosion identification on pipes. The objective of this paper is to identify corrosion on pipes from vibration measurements. A hollow pipe, 500 mm in length with 63.5 mm in diameter was subjected to impact loading using an impact hammer to identify the natural frequency of the tube in two conditions i) without any corrosion and ii) with an induced localized 40 mm by 40 mm corrosion at the middle of the pipe. The shift of natural frequencies of the structures under free boundary conditions was examined for each node of excitation. The results showed that there is a shift in natural frequency of the pipe, between 3 and 4 Hz near to the corrosion area. It can suggested that that the impact vibration is capable of identifying of localized corrosion on a hollow tube.

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