Acoustic insulation characteristics of sandwich composite shell systems with double curvature: The effect of nature of viscoelastic core

Seilsepour, Hasan; Zarastvand, M.R.; Talebitooti, Roohollah

doi:10.1177/10775463211056758

Cited by 40 publications

(7 citation statements)

References 27 publications

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“…The pipe is a viscoelastic material subject to Kelvin-Voigt [41,42]-type internal dissipation and follows the following stress-strain relationship.…”

Section: Analytical Simulationmentioning

confidence: 99%

Investigation of Dynamic Behavior of Ultra-Large Cold-Water Pipes for Ocean Thermal Energy Conversion

Zhang,

Zheng,

Zhang

et al. 2023

Dynamics

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Ocean Thermal Energy Conversion (OTEC) is a process that can produce electricity by utilizing the temperature difference between deep cold water and surface warm water. The cold-water pipe (CWP) is a key component of OTEC systems, which transports deep cold water to the floating platform. The CWP is subjected to various environmental and operational loads, such as waves, currents, internal flow, and platform motion, which can affect its dynamic response and stability. In this paper, we establish a computational model of the mechanical performance of the CWP based on the Euler–Bernoulli beam theory and the Morrison equation, considering the effects of internal flow, sea current, and wave excitation. We use the differential quadrature method (DQM) to obtain a semi-analytical solution of the lateral displacement and bending moment of the CWP. We verify the correctness and validity of our model by comparing it with the finite element simulation results using OrcaFlex software. We also analyze the effects of operating conditions—such as wave intensity, clump weight at the bottom, and internal flow velocity—on the dynamic response of the CWP using numerical simulation and the orthogonal experimental method. The results show that changing the wave strength and internal flow velocity has little effect on the lateral displacement of the CWP but increasing the current velocity can significantly increase the lateral displacement of the CWP, which can lead to instability. The effects of waves, clump weight, internal flow, and sea current on the maximum bending moment of the CWP are similar; all of them increase sharply at first and then decrease gradually until they level off. The differences in the effects are mainly reflected in the different locations of the pipe sections. This paper suggests some design guidance for CWP in terms of dynamic responses depending on the operating conditions. This paper contributes to the journal’s scope by providing a novel and efficient method for analyzing the mechanical performance of CWP for OTEC systems, which is an important ocean energy resource.

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“…The pipe is a viscoelastic material subject to Kelvin-Voigt [41,42]-type internal dissipation and follows the following stress-strain relationship.…”

Section: Analytical Simulationmentioning

confidence: 99%

Investigation of Dynamic Behavior of Ultra-Large Cold-Water Pipes for Ocean Thermal Energy Conversion

Zhang,

Zheng,

Zhang

et al. 2023

Dynamics

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“…The wave propagation characteristics of nanobeams using a high-order nonlocal strain gradient elasticity theory considering thickness stretching effect under the influence of hygrothermal environment was investigated (Karami et al, 2021). It is to be pointed out that there are some important works in the field of wave characteristics of the plates and shells can be addressed as radiated sound control from a smart cylinder with finite length using patches as sensors and actuators (Gohari et al, 2020), acoustically power transmission of stimulated and thermally loaded composite shells with double curvature surrounded by a rigid baffle (Rahmatnezhad et al, 2021), a review on prediction of acoustic wave transmission features of the multilayered plate constructions (Zarastvand et al, 2021) and an investigation on the effect of nature of viscoelastic core on the acoustic insulation characteristics of sandwich composite shell with double curvature (Seilsepour et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Nonlocal wave propagation analysis of a rotating nanobeam on a Pasternak foundation

Farhadipour

Mamandi

2023

Journal of Vibration and Control

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In this paper, the wave propagation analysis of a cantilever rotating nanobeam modeled as a thin beam based on the Euler–Bernoulli theory on a Pasternak foundation has been investigated using the nonlocal theory of elasticity. The governing partial differential equation of motion for a uniform rotating nanobeam is derived using the Hamilton principle considering the nonlocal parameter of small scale effect. The Spectrum and dispersion relations of non-dimensional wave number are obtained analytically. The effect of changes of different parameters including nonlocal scale parameter, non-dimensional rotational speed, non-dimensional rotational wave frequency ratio, and shear stiffness of the Pasternak foundation on the wave dispersion behavior of the non-dimensional wave number and phase and group speeds dispersions for the rotating nanotube have been studied. It is observed that the wave dispersion characteristics of the rotating nanobeam are extremely influenced by rotational speed, wave number, nonlocal length scale parameter, and shear stiffness of the Pasternak foundation. Moreover, the propagated flexural wave has been shown to exhibit non-dispersive behavior at very high rotational speeds.

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“…However, these methods are not used in aircraft hydraulic systems. In a real aircraft hydraulic system working environment, noises exist on a wide frequency range, which may result in violent changes, and this situation makes it difficult to conduct fault diagnosis [22,23]. Therefore, the proposed methods cannot be effective in such a noisy environment.…”

Section: Introductionmentioning

confidence: 99%

An EMD-LSTM Deep Learning Method for Aircraft Hydraulic System Fault Diagnosis under Different Environmental Noises

Shen

Zhao

2023

Aerospace

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Aircraft hydraulic fault diagnosis is an important technique in aircraft systems, as the hydraulic system is one of the key components of an aircraft. In aircraft hydraulic system fault diagnosis, complex environmental noises will lead to inaccurate results. To address the above problem, hydraulic system fault detection methods should be capable of noise resistance. Previous research has mainly focused on noise-free conditions and many effective approaches have been proposed; however, in real-world aircraft flying conditions, the aircraft hydraulic system often has strong and complex noises. The methods proposed may not have good fault detection results in such a noisy environment. According to the situation, this work focuses on aircraft hydraulic system fault classification under the influence of a hydraulic working environment with Gaussian white noise. In order to eliminate the noise interference and adapt to the actual noisy environment, a new aircraft hydraulic fault diagnostic method based on empirical mode deposition (EMD) and long short-term memory (LSTM) is presented. First, the hydraulic system is constructed by AMESIM. One normal state and five fault states are considered in this paper. Eight-channel signals of different states are collected for network training and testing. Second, the EMD method is used to obtain the different intrinsic mode functions (IMFs) of the signals. Third, principal component analysis (PCA) is used to obtain the main component of the IMFs. Fourth, three different LSTM methods are chosen to compare and the best structure that is chosen is the gate recurrent unit (GRU). After that, the network parameters are optimized. The results under different noise environments are given. Then, a comparison between the EMD-GRU with several different machine learning methods is considered, and the result shows that the method in this paper has a better anti-noise effect. Therefore, the proposed method is demonstrated to have a strong ability of fault diagnosis and classification under the working noises based on the simulation results.

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Acoustic insulation characteristics of sandwich composite shell systems with double curvature: The effect of nature of viscoelastic core

Cited by 40 publications

References 27 publications

Investigation of Dynamic Behavior of Ultra-Large Cold-Water Pipes for Ocean Thermal Energy Conversion

Investigation of Dynamic Behavior of Ultra-Large Cold-Water Pipes for Ocean Thermal Energy Conversion

Nonlocal wave propagation analysis of a rotating nanobeam on a Pasternak foundation

An EMD-LSTM Deep Learning Method for Aircraft Hydraulic System Fault Diagnosis under Different Environmental Noises

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