Shock transmission in a coupled beam system

Vijayan, Kiran; Woodhouse, J.

doi:10.1016/j.jsv.2013.02.024

Cited by 17 publications

(6 citation statements)

References 3 publications

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“…In the case of periodic structures, the perfect symmetry yields repeated eigenvalues, for example k 1 ¼ k 2 . However, in the presence of parametric uncertainties the symmetry is broken and the repeating eigenvalues are split into distinct values [30][31][32]. This change in the eigenvector, due to some variation of the mass and stiffness matrices in the system, is what has to be quantified.…”

Section: Background Of Mode Veeringmentioning

confidence: 99%

Quantification of Vibration Localization in Periodic Structures

Chandrashaker

Adhikari

Friswell

2016

Journal of Vibration and Acoustics

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The phenomenon of vibration mode localization in periodic and near periodic structures has been well documented over the past four decades. In spite of its long history, and presence in a wide range of engineering structures, the approach to detect mode localization remains rather rudimentary in nature. The primary way is via a visual inspection of the mode shapes. For systems with complex geometry, the judgment of mode localization can become subjective as it would depend on visual ability and interpretation of the analyst. This paper suggests a numerical approach using the modal data to quantify mode localization by utilizing the modal assurance criterion (MAC) across all the modes due to changes in some system parameters. The proposed MAC localization factor (MACLF) gives a value between 0 and 1 and therefore gives an explicit value for the degree of mode localization. First-order sensitivity based approaches are proposed to reduce the computational effort. A two-degree-of-freedom system is first used to demonstrate the applicability of the proposed approach. The finite element method (FEM) was used to study two progressively complex systems, namely, a coupled two-cantilever beam system and an idealized turbine blade. Modal data is corrupted by random noise to simulate robustness when applying the MACLF to experimental data to quantify the degree of localization. Extensive numerical results have been given to illustrate the applicability of the proposed approach.

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Section: Background Of Mode Veeringmentioning

confidence: 99%

Quantification of Vibration Localization in Periodic Structures

Chandrashaker

Adhikari

Friswell

2016

Journal of Vibration and Acoustics

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“…, where in the presence of parametric uncertainties the symmetry is broken and the repeating eigenvalues are split into distinct values [8][9][10]. Examining the derivative of the eigenvector expressed by [11] can provide an insight into the curve veering phenomena…”

Section: Background Of Mode Veeringmentioning

confidence: 99%

Vibration Localization of Rotationally Periodic Structures

Chandrashaker

Adhikari

2014

Mechanisms and Machine Science

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Structures with uniform periodic spacing and repeated geometry are found in complex engineering systems. Examples include turbine blades, ship hull, aircraft fuselage and oil pipelines with periodic supports. The vibration characteristics of these periodic structures are highly sensitive to its mass distribution, stiffness distribution and geometrical properties. Parametric uncertainties in structures which arise out of material defects, structural damage or variations in material properties can break the symmetry of periodic structures. These uncertainties can drastically change and localize the vibration modes. Identification of severe mode localization in the design process can help prevent failure due to high cycle fatigue in periodic structures such as turbine blades. A 2-DOF system is used to demonstrate the effect of parametric uncertainties on eigenvalue veering and mode localization phenomenon. The Finite Element Method (FEM) was developed to study the free vibrations of two linearly un-damped systems, namely, two cantilever beams coupled system and an idealized turbine blade. The effect of parametric uncertainties on eigenvalue veering and mode localization is demonstrated and a novel numerical method using the Modal Assurance Criterion (MAC) to quantify mode localization in complex systems is proposed.

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“…Dynamic characteristics (stiffness and damping matrices) can provide insights into the fatigue life of the structure. The stiffened structure was modeled as a coupled system comprising of two subsystems along with a coupling element [27,28,42,43]. For an assembly of welding joints having the same dimension, the joint parameters could be different for each case due to uncertainties.…”

Section: Introductionmentioning

confidence: 99%