scholarly journals Influence of Hole Localization on Local and Global Dynamic Response of Thin-Walled Laminated Cantilever Beam

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7409
Author(s):  
Marcin Bochenski ◽  
Jaroslaw Gawryluk ◽  
Andrzej Teter
Keyword(s):  
Dynamic Response ◽  
Cantilever Beam ◽  
The Finite Element Method ◽  
Local Modes ◽  
Numerical Tests ◽  
Global Dynamic ◽  
Eigen Frequencies ◽  
Thin Walled ◽  
Global And Local ◽  
Abaqus Software

In this study, we discuss the effects of the diameter and position of a hole on the dynamic response of a thin-walled cantilever beam made of carbon-epoxy laminate. Eigen-frequencies and corresponding global and local eigen-modes were considered, where deformations of the beam wall were dominant, without significant deformation of the beam axis. The study was focused on the circumferentially uniform stiffness (CUS) beam configuration. The laminate layers were arranged as [90/15(3)/90/15(3)/90]T. The finite element method was employed for numerical tests, using the Abaqus software package. Moreover, a few numerical results of the structure’s behaviour, with and without a hole, were verified experimentally. The experimental eigen-frequencies and the corresponding modes were obtained using an experimental modal analysis, comprising the LMS system with modal hammer. We found that the size and location of the hole affected the eigen-frequencies and corresponding modes. Furthermore, even a small hole in a beam could significantly change the shape of its local modes. The numerical and experimental results were observed to have high qualitative compliance.

scholarly journals Springing Analysis of a Passenger Ship in Waves

2020 ◽  
Vol 8 (7) ◽  
pp. 492 ◽  
Author(s):  
Jeremias Tilander ◽  
Matthew Patey ◽  
Spyros Hirdaris
Keyword(s):  
Dynamic Response ◽  
Direct Analysis ◽  
Medium Size ◽  
Global Dynamic ◽  
Passenger Ship ◽  
Passenger Ships ◽  
Wave Energy Spectrum ◽  
Global And Local ◽  
Wave Induced ◽  
Classification Society

Traditionally, the evaluation of global loads experienced by passenger ships has been based on closed-form Classification Society Rule formulae or quasi direct analysis procedures. These approaches do not account for the combined influence of hull flexibility, slenderness, and environmental actions on global dynamic response. This paper presents a procedure for the prediction of the global wave-induced loads of a medium-size passenger ship using a potential flow Flexible Fluid Structure Interaction (FFSI) model. The study compares results from direct long-term hydro-structural computations against Classification Society Rules. It is demonstrated that for the specific vessel under consideration: (a) the elastic contributions of the responses on loads are negligible as springing effects occur outside of the wave energy spectrum, (b) deviations of the order of 28% arise by way of amidships when comparing direct hydrodynamic analysis predictions encompassing IACS UR S11A hog/sag nonlinear correction factors and the longitudinal strength standard, and (c) the interpretation of the wave scatter diagram influences predictions by approximately 20%. Based on these indications, it is recommended that further parametric studies over a range of passenger ship designs could help draw unified conclusions on the total influence of global and local hydrodynamic actions on passenger ship loads and dynamic response.

Dynamic Mechanical Behaviour of Innovative Structures Incorporating Cork

2008 ◽  
Vol 587-588 ◽  
pp. 599-603 ◽  
Author(s):  
C.P. Gameiro ◽  
José Cirne
Keyword(s):  
Mechanical Behaviour ◽  
High Strain ◽  
Strain Rates ◽  
The Finite Element Method ◽  
Metallic Structures ◽  
Dynamic Mechanical ◽  
Numerical Tests ◽  
Absorbing Material ◽  
Thin Walled ◽  
Energy Absorbing

Cork is a natural cellular material which has been used for centuries, in natural and agglomerate forms, mainly for applications related to the wine, the automotive and the construction industries. It is a very durable and ecological material, used for thermal, acoustic and vibrating insulation as well as packaging, among others. This paper highlights some of the aspects of a topic of great interest, not much explored yet, which consists of the study of the dynamic mechanical behaviour of innovative structures incorporating cork, dedicated to energy-absorption. Experimental and numerical tests, using the finite element method software LS-DYNA™, were performed in order to evaluate the effects of filling agglomerate cork inside thin-walled metallic tubes, with variable geometries and thicknesses, impacted uniaxially at quasi-static and high strain rates. Some relevant comparisons were carried out and the results obtained allowed concluding that cork might be a viable energy-absorbing material for application in some metallic structures subjected to impact loadings.

Dynamic Response of Spiral Cantilever Undergoing Magnetic Coupling

2014 ◽  
Vol 14 (08) ◽  
pp. 1440021
Author(s):  
Xiaoling Bai ◽  
Yumei Wen ◽  
Ping Li ◽  
Jin Yang ◽  
Xiao Peng ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Cantilever Beam ◽  
Magnetic Force ◽  
Coupling Effect ◽  
Magnetic Coupling ◽  
Resonant Frequencies ◽  
Energy Harvesters ◽  
Magnetic Transducer ◽  
Underlying Mechanisms ◽  
Tip Mass

Cantilever beams have found intensive and extensive uses as underlying mechanisms for energy transduction in sensors as well as in energy harvesters. In magnetoelectric (ME) transduction, the underlying cantilever beam usually will undergo magnetic coupling effect. As the beam itself is either banded with magnetic transducer or magnets, the dynamic motion of the cantilever can be modified due to the magnetic force between the magnets and ME sensors. In this study, the dynamic response of a typical spiral cantilever beam with magnetic coupling is investigated. The spiral cantilever acts as the resonator of an energy harvester with a tip mass in the form of magnets, and a ME transducer is positioned in the air gap and interacts with the magnets. It is expected that this spiral configuration is capable of performing multiple vibration modes over a small frequency range and the response frequencies can be magnetically tunable. The experimental results show that the magnetic coupling between the magnets and the transducer plays a favorable role in achieving tunable resonant frequencies and reducing the frequency spacings. This will benefits the expansion of the response band of a device and is especially useful in energy harvesting.

Effect of payloads contact upon the coupled dynamic response of two cooperating robots

Robotica ◽  
1996 ◽  
Vol 14 (6) ◽  
pp. 659-665
Author(s):  
G. Shagal ◽  
S.A. Meguid
Keyword(s):  
Dynamic Response ◽  
Function Method ◽  
Search Algorithm ◽  
Contact Region ◽  
Dynamic Equations ◽  
Penalty Function Method ◽  
The Finite Element Method ◽  
Contact Search ◽  
Cooperating Robots ◽  
Lagrange’S Method

The coupled dynamic response of two cooperating robots handling two flexible payloads is treated using a new algorithm. In this algorithm, the dynamic equations describing the system are obtained using Lagrange's method for the rigid robot links and the finite element method for the flexible payloads. The contact between the flexible payloads is modelled using the penalty function method and a contact search algorithm is employed to identify the contact region.

Dynamic Behavior of Aircraft Wings Modeled as Doubly-Tapered Composite Thin-Walled Beams

1999 ◽  
Author(s):  
Sungsoo Na ◽  
Liviu Librescu
Keyword(s):  
Composite Materials ◽  
Free Vibration ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Transverse Shear ◽  
Dynamical Behavior ◽  
Time Dependent ◽  
Aircraft Wings ◽  
Helicopter Blades ◽  
Thin Walled

Abstract A study of the dynamical behavior of aircraft wings modeled as doubly-tapered thin-walled beams, made from advanced anisotropic composite materials, and incorporating a number of non-classical effects such as transverse shear, and warping inhibition is presented. The supplied numerical results illustrate the effects played by the taper ratio, anisotropy of constituent materials, transverse shear flexibility, and warping inhibition on free vibration and dynamic response to time-dependent external excitations. Although considered for aircraft wings, this analysis and results can be also applied to a large number of structures such as helicopter blades, robotic manipulator arms, space booms, tall cantilever chimneys, etc.

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