Search

• A symplectic analytical wave propagation model is proposed for the forced vibration of ABH indentation plate. • ABH indentation can significantly reduce vibration of plates in the whole frequency range. • Embedding plates with multiple ABH indentations can increase stiffness without losing the ABH effect. • The ABH indentation plate with reinforcing stiffeners is proposed to alleviate the stiffness loss. • The quantity of stiffener has significant impact on the ABH effect. In recent years, acoustic black holes (ABHs) have been revealed as an effective bending wave control technology and widely used to regulate the vibration and noise reduction performance of plate structure. However, the isolation effect of most traditional ABH plate can only be aroused at frequencies above the cut-off frequency. In order to widen the frequency range of the ABH effect, this paper embedded single and multiple ABH indentations at the end of plate. For the forced vibration response of the ABH indentation plate, an analytical wave propagation model was proposed based on the symplectic method. The governing equations of bending vibration of thin plate was first introduced into the symplectic dual system, then the symplectic analytical solution of wave propagation parameters and waveforms were obtained. A Gaussian-discretization scheme was used to discretize the ABH indentation, whereas the proposed method was used to evaluate the wave amplitude. The vibration response was finally obtained using the superposition principle and wave propagation, reflection, and transmission relationships. The effectiveness of the proposed method was verified using the finite element results. The results showed that the ABH indentation plate, especially the plate with multiple ABH indentations, had significant vibration reduction performance. Considering that embedding ABH indentation can weaken the structural rigidity of the plate, the ABH indentation plate with reinforcing stiffeners was then proposed to alleviate this limitation, and the influence of the width and quantity of reinforcing stiffeners on the vibration response was studied. The results indicated that the increase of width will to some extent weaken the ABH effect, and the quantity of stiffeners had a significant impact on the ABH effect. [ABSTRACT FROM AUTHOR]

• The mechanism of the action of corrugated plates on solitary waves was studied. • A predicted model for the film thickness under turbulent conditions is proposed. • The prediction model considers wall structural parameters and Re l. The effect of wall distortion of the scrubbing-cooling tube on turbulent falling film is significant. The wall distortion was simplified by using corrugated plates; the effect of structural parameters (amplitude and wavelength) of corrugated plates on the action mechanism of solitary waves and the axial distribution of liquid film thickness were investigated. The results show that the Coanda effect decelerates and accelerates the flowing liquid film attached to the wall, which leads to the generation and extinction of solitary waves on the liquid film. The intensification of the local perturbation easily promotes the solitary waves to form slender water columns. Under the effect of Plateau-Rayleigh instability, the tails of the slender water columns break up to form tiny droplets. The mean liquid film thickness prediction model can accurately predict the mean liquid film thickness on corrugated plates (amplitude/wavelength = 0.02 ∼ 0.08) and the relative errors within ± 15%. [ABSTRACT FROM AUTHOR]

• We proposed a method to measure dispersion curves base on clustering algorithms. • The method could realize more accurate and reliable measurement results with less measured data. • This method was experimentally verified with an isotropic aluminum plate and an anisotropic CFRP plate. • We obtain A 0 mode phase-velocity dispersion curves for CFRP plate with various braiding angles. Due to the large detection range and high sensitivity to damages, Lamb waves are widely used in the localization and quantification of structural damages in a plate structure. The dispersion curve measurement is significant in the applications of Lamb waves, especially in a material with unknown properties. In the study, a method was proposed to measure dispersion curves based on clustering. Compared with traditional methods, the proposed method could realize more accurate and reliable measurement results with less measured data. This method was experimentally verified with an isotropic aluminum plate and an anisotropic CFRP plate. The relative error between measured and real values in an aluminum plate was less than 1%. With this method, A 0 mode phase-velocity dispersion curves in CFRP plate with various braiding angles were experimentally obtained. This method facilitated Lamb wave defect detection and material parameter inversion. [ABSTRACT FROM AUTHOR]