Modal analysis of a submerged spherical point absorber with asymmetric mass distribution

A method of modal analysis by a mass-weighted proper orthogonal decomposition for multi-degree-of-freedom and distributed-parameter systems of arbitrary mass distribution is outlined. The method involves reduced-order modeling of the system mass distribution so that the discretized mass matrix dimension matches the number of sensed quantities, and hence the dimension of the response ensemble and correlation matrix. In this case, the linear interpolation of unsensed displacements is used to reduce the size of the mass matrix. The idea is applied to the modal identification of a mass-spring system and an exponential rod.

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A sensitivity study on the effect of mass distribution of a single-tether spherical point absorber

Renewable Energy ◽

10.1016/j.renene.2019.03.149 ◽

2019 ◽

Vol 141 ◽

pp. 583-595 ◽

Cited By ~ 3

Author(s):

Fantai Meng ◽

Benjamin Cazzolato ◽

Ye Li ◽

Boyin Ding ◽

Natalia Sergiienko ◽

...

Keyword(s):

Mass Distribution ◽

Sensitivity Study ◽

Point Absorber

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Modal analysis and structure optimisation of vehicle seat frame based on mass distribution method

International Journal of Vehicle Design ◽

10.1504/ijvd.2018.100094 ◽

2018 ◽

Vol 78 (1/2/3/4) ◽

pp. 1

Author(s):

Zheng Zhang ◽

Dong Ye ◽

Congda Lu ◽

Feng Li ◽

Yi Huang ◽

...

Keyword(s):

Modal Analysis ◽

Mass Distribution ◽

Distribution Method ◽

Seat Frame ◽

Vehicle Seat

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Nonlinear hydrodynamics analysis of a submerged spherical point absorber with asymmetric mass distribution

Renewable Energy ◽

10.1016/j.renene.2019.09.101 ◽

2020 ◽

Vol 147 ◽

pp. 1895-1908 ◽

Cited By ~ 1

Author(s):

Fantai Meng ◽

Ashkan Rafiee ◽

Boyin Ding ◽

Benjamin Cazzolato ◽

Maziar Arjomandi

Keyword(s):

Mass Distribution ◽

Point Absorber ◽

Nonlinear Hydrodynamics

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Modal analysis and structure optimisation of vehicle seat frame based on mass distribution method

International Journal of Vehicle Design ◽

10.1504/ijvd.2018.10021745 ◽

2018 ◽

Vol 78 (1/2/3/4) ◽

pp. 1

Author(s):

Congda Lu ◽

Feng Li ◽

Yi Huang ◽

Huaping Wu ◽

Shaofei Jiang ◽

...

Keyword(s):

Modal Analysis ◽

Mass Distribution ◽

Distribution Method ◽

Seat Frame ◽

Vehicle Seat

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Scaling Mode Shapes in Output-Only Structure by a Mass-Change-Based Method

Shock and Vibration ◽

10.1155/2017/2617534 ◽

2017 ◽

Vol 2017 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Liangliang Yu ◽

Hanwen Song

Keyword(s):

Modal Analysis ◽

Mass Distribution ◽

Null Space ◽

Mass Matrix ◽

Small Mass ◽

Mass Change ◽

Mode Shapes ◽

Distribution Matrix ◽

Distribution Vector ◽

Output Only

A mass-change-based method based on output-only data for the rescaling of mode shapes in operational modal analysis (OMA) is introduced. The mass distribution matrix, which is defined as a diagonal matrix whose diagonal elements represent the ratios among the diagonal elements of the mass matrix, is calculated using the unscaled mode shapes. Based on the theory of null space, the mass distribution vector or mass distribution matrix is obtained. A small mass with calibrated weight is added to a certain location of the structure, and then the mass distribution vector of the modified structure is estimated. The mass matrix is identified according to the difference of the mass distribution vectors between the original and modified structures. Additionally, the universal set of modes is unnecessary when calculating the mass distribution matrix, indicating that modal truncation is allowed in the proposed method. The mass-scaled mode shapes estimated in OMA according to the proposed method are compared with those obtained by experimental modal analysis. A simulation is employed to validate the feasibility of the method. Finally, the method is tested on output-only data from an experiment on a five-storey structure, and the results confirm the effectiveness of the method.

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Modal analysis of an underwing search-light fairing

AUTOBUSY – Technika Eksploatacja Systemy Transportowe ◽

10.24136/atest.2019.025 ◽

2019 ◽

Vol 20 (1-2) ◽

pp. 147-150

Author(s):

Jarosław Bednarz ◽

Wojciech Lisowski

Keyword(s):

Numerical Analysis ◽

Modal Analysis ◽

Mass Distribution ◽

Structural Dynamics ◽

Experimental Modal Analysis ◽

Flight Tests ◽

Analysis Techniques ◽

Aerodynamic Properties ◽

Local Stiffness ◽

Attachment Place

Many applications of aircraft require using dedicated elements of equipment attached to the fuselage or wings. These elements change aerodynamic properties of the aircraft. They modify spatial mass distribution and local stiffness in the attachment place. Structural dynamics of the modified airframe is usually investigated with use of the numerical analysis techniques. Verification of results of such the analysis is carried out experimentally. The basic method of testing is the experimental modal analysis. In the paper, there is presented an exemplary application of the experimental modal analysis to testing of a modified airplane structure with a search-light covered by its fairing attached under a wing. The described experiments consisted of the ground as well as the in-flight tests. The paper reports description and results of the experiments.

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Analysis of the stiffness sensitivity of a sorting arm mechanism based on a generalized modal mass distributing matrix

Advances in Mechanical Engineering ◽

10.1177/1687814018810639 ◽

2018 ◽

Vol 10 (11) ◽

pp. 168781401881063

Author(s):

Xuchu Jiang ◽

Bin Li ◽

Hongqi Liu ◽

Songping He ◽

Xinyong Mao ◽

...

Keyword(s):

Modal Analysis ◽

Mass Distribution ◽

High Speed ◽

Degrees Of Freedom ◽

Light Emitting Diode ◽

Positional Accuracy ◽

Operation Conditions ◽

The Matrix ◽

Distribution Matrix ◽

Modal Mass

A light-emitting diode chip sorting machine, which operates at high frequencies, exhibits reciprocating motion with multiple degrees of freedom and is characterized by quick starts and stops over a short range at a high frequency. The stiffness sensitivity of the chip sorter directly influences the positional accuracy of the sorting arm. However, existing experimental modal analysis methods cannot effectively identify the structural stiffness sensitivity under high-speed operation conditions. In this article, a method based on the modal mass distribution matrix is used to analyze the stiffness sensitivity of the sorting arm system. This method retrieves the modal parameters by modal analysis, after which the modal mass distribution matrix is obtained. The size of each element in the column of the matrix represents the energy distribution and stiffness sensitivity of the system under the mode. The stiffness-sensitive components of the sorting arm machine are accurately and quickly identified, thereby providing the guiding principle and basis for the dynamic optimization of the sorting arm mechanism.

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The application of modal analysis to the design of multi-mode point absorber wave energy converters

Ocean Engineering ◽

10.1016/j.oceaneng.2018.11.058 ◽

2019 ◽

Vol 171 ◽

pp. 603-618 ◽

Cited By ~ 5

Author(s):

Boyin Ding ◽

Nataliia Sergiienko ◽

Fantai Meng ◽

Benjamin Cazzolato ◽

Peter Hardy ◽

...

Keyword(s):

Modal Analysis ◽

Wave Energy ◽

Point Absorber ◽

Wave Energy Converters ◽

Multi Mode ◽

Energy Converters

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Reduced Mass-Weighted Proper Decomposition for Modal Analysis

Smart Materials, Adaptive Structures and Intelligent Systems, Volume 2 ◽

10.1115/smasis2008-584 ◽

2008 ◽

Author(s):

Venkata K. Yadalam ◽

B. F. Feeny

Keyword(s):

Modal Analysis ◽

Mass Distribution ◽

Mass Matrix ◽

Linear Interpolation ◽

Modal Identification ◽

Lumped Mass ◽

Arbitrary Mass ◽

Spring System ◽

Mass Spring ◽

Proper Orthogonal

A method of modal analysis by proper orthogonal decomposition for large-order systems of arbitrary mass distribution is outlined. The method involves reduced-order modeling of the system mass distribution so that the discretized mass matrix dimension matches the number of sensed quantities, and hence the dimension of the response ensemble and correlation matrix. In this case, the linear interpolation of unsensed displacements is used to perform an effective lumped mass homogenization. The idea is applied to the modal identification of a mass-spring system and an exponential rod.

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