A Numerical and Experimental Study on an Interconnected Metamaterial for Flexural Vibration Control Based on Modal Strain Energy

In this study, an interconnected metamaterial was proposed to suppress flexural vibration. The interconnected metamaterial can improve the manufacturing and installation processes in terms of convenience because it can be fabricated in the form of a modular multi-celled structure with a single-phase material. To evaluate the vibration reduction performance of the metamaterial, stopband analysis was performed, as it solves an iterative eigenvalue problem for the wave vector domain. In order to identify the Bloch mode that contributes to flexural vibration, a concept to extract the Bloch mode based on the modal strain energy was proposed. The vibration-reduction performance of the interconnected metamaterial was numerically verified by using a frequency-response analysis of the multi-celled structure. The interconnected metamaterial proposed in this study was fabricated by using a 3D printer. Finally, the vibration-reduction performance of the multi-celled structure was experimentally verified by using impact testing.

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Analysis of Modal Parameters of Adhesively Bonded Double-Strap Joints by the Modal Strain Energy Method

14th Biennial Conference on Mechanical Vibration and Noise: Vibration Isolation, Acoustics, and Damping in Mechanical Systems ◽

10.1115/detc1993-0242 ◽

1993 ◽

Author(s):

Mohan D. Rao ◽

Krishna M. Gorrepati

Keyword(s):

Strain Energy ◽

Natural Frequencies ◽

Structural Parameters ◽

Flexural Vibration ◽

Mode Shapes ◽

Modal Parameters ◽

Adhesively Bonded ◽

Modal Strain Energy ◽

Joint System ◽

Damping Material

Abstract This paper presents the analysis of modal parameters (natural frequencies, damping ratios and mode shapes) of a simply supported beam with adhesively bonded double-strap joint by the finite-element based Modal Strain Energy (MSE) method using ANSYS 4.4A software. The results obtained by the MSE method are compared with closed form analytical solutions previously obtained by the first author for flexural vibration of the same system. Good agreement has been obtained between the two methods for both the natural frequencies and system loss factors. The effects of structural parameters and material properties of the adhesive on the modal properties of the joint system are also studied which are useful in the design of the joint system for passive vibration and noise control. In order to evaluate the MSE and analytical results, some experiments were conducted using aluminum double-strap joint with 3M ISD112 damping material. The experimental results agreed well with both analytical and MSE results indicating the validity of both analytical and MSE methods. Finally, a comparative study has been conducted using various commercially available damping materials to evaluate their relative merits for use in the design of these joints.

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Frequency Response Analysis Technique of Short Circuit Faults Detection in Photovoltaic Single-Phase Inverter Experimental Study

European Journal of Electrical Engineering ◽

10.18280/ejee.230407 ◽

2021 ◽

Vol 23 (4) ◽

pp. 337-343

Author(s):

Ouadfel Ghania ◽

Houassine Hamza ◽

Gacemi Abderzak ◽

Bensaid Samir

Keyword(s):

Frequency Response ◽

Fault Location ◽

Single Phase ◽

Short Circuit ◽

Response Analysis ◽

Frequency Response Analysis ◽

Phase Inverter ◽

Efficient Detection ◽

Healthy State ◽

Single Phase Inverter

The work proposed in this paper concerns the study of short circuit faults in a single-phase inverter dedicated to a photovoltaic application by applying the frequency response analysis (FRA) technique on this IGBT-based inverter controlled by a 18F2550 microcontroller, a prototype inverter was designed in the laboratory to be able to apply off-line short-circuit faults using an LRC meter. The FRA technique is based on the comparison of amplitude-frequency and phase-frequency signatures of healthy cases and fault situations. The experimental results also led to the conclusion that frequency response analysis can be used as an effective tool to detect faults in power electronic devices. This method allows for efficient detection and classification of faults with ease of implementation. For fault location, the fault branch is determined according to its position relative to its healthy state.

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Analysis of Modal Parameters of Adhesively Bonded Double-Strap Joints by the Modal Strain Energy Method

Journal of Vibration and Acoustics ◽

10.1115/1.2889631 ◽

1996 ◽

Vol 118 (1) ◽

pp. 28-35 ◽

Cited By ~ 9

Author(s):

K. M. Gorrepati ◽

M. D. Rao

Keyword(s):

Strain Energy ◽

Natural Frequencies ◽

Structural Parameters ◽

Flexural Vibration ◽

Mode Shapes ◽

Modal Parameters ◽

Adhesively Bonded ◽

Modal Strain Energy ◽

Joint System ◽

Damping Material

This paper presents the analysis of modal parameters (natural frequencies, damping and mode shapes) of a simply supported beam with adhesively bonded double-strap joint by the finite-element based Modal Strain Energy (MSE) method using ANSYS 4.4A software. The results obtained by the MSE method are compared with closed form analytical solutions previously obtained by the author for flexural vibration of the same system. Good agreement has been obtained between the two methods for both the natural frequencies and system loss factors. The effects of structural parameters and material properties of the adhesive on the modal properties of the joint system are also studied which are useful in the design of the joint system for passive vibration and noise control. In order to evaluate the MSE and analytical results, some experiments were conducted using aluminum double-strap joints with 3M ISD112 damping material. The experimental results agreed well with both analytical and MSE results indicating the validity of both analytical and MSE methods. Finally, a comparative study has been conducted using various commercially available damping materials to evaluate their relative merits for use in the design of these joints.

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High-Frequency Modeling of a Three-Winding Power Transformer Using Sweep Frequency Response Analysis

Energies ◽

10.3390/en14134009 ◽

2021 ◽

Vol 14 (13) ◽

pp. 4009

Author(s):

Yeunggurl Yoon ◽

Yongju Son ◽

Jintae Cho ◽

SuHyeong Jang ◽

Young-Geun Kim ◽

...

Keyword(s):

Frequency Response ◽

Single Phase ◽

Power Transformer ◽

Response Analysis ◽

Model Parameters ◽

Frequency Response Analysis ◽

Sweep Frequency ◽

Individual Parameter ◽

Simulation Based ◽

Transformer Model

A power transformer is an essential device for stable and reliable power transfer to customers. Therefore, accurate modeling of transformers is required for simulation-based analysis with the model. The paper proposes an efficient and straightforward parameter estimation of power transformers based on sweep frequency response analysis (SFRA) test data. The method first develops a transformer model consisting of repetitive RLC sections and mutual inductances and then aligns the simulated SFRA curve with the measured one by adjusting parameters. Note that this adjustment is based on individual parameter impacts on the SFRA curve. After aligning the two curves, the final transformer model can be obtained. In this paper, actual single-phase, three-winding transformer model parameters were estimated based on field SFRA data, showing that SFRA curves simulated from the estimated model are consistent with the measured data.

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