Article
Acoustics
Salvador Rodriguez-Blanco, Javier Gonzalez-Monge, Carlos Martel
Summary: In modern LPT designs, the simultaneous presence of forced response and flutter in different operation regimes is unavoidable. Recent evidence suggests that the traditional linear superposition method may be overly conservative. This study examines the flutter and forced response interaction in a realistic low pressure turbine rotor and confirms that the actual response is much smaller than that predicted by linear superposition.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Kabilan Baskaran, Nur Syafiqah Jamaluddin, Alper Celik, Djamel Rezgui, Mahdi Azarpeyvand
Summary: This study investigates the impact of the number of blades on the aeroacoustic characteristics and aerodynamic performance of propellers used in urban air mobility vehicles. The results show that different blade numbers exhibit distinct noise levels, providing valuable insights for further research on propeller noise and aerodynamic performance.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Nicco Ulbricht, Alain Boldini, Peng Zhang, Maurizio Porfiri
Summary: The quantification of fluid-structure interactions in marine structures is crucial for their design and optimization. In this study, an analytical solution for the free vibration of a bidirectional composite in contact with a fluid is proposed. By imposing continuity conditions and boundary conditions, the coupled fluid-structure problem is solved and applied to sandwich structures in naval construction, offering insights into the effects of water on mode shapes and through-the-thickness profiles of displacement and stress.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Yongbo Peng, Peifang Sun
Summary: This study focuses on the reliability-based design optimization (RBDO) of the tuned mass-damper-inerter (TMDI) system under non-stationary excitations. The performance of the optimized TMDI system is evaluated using probability density evolution analysis. The results demonstrate the technical advantages of TMDI, including high vibration mitigation performance, considerable mass reduction, and less stroke demand.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Pengfei Deng, Xing Tan, He Li
Summary: In this paper, the authors improve the surface morphology method and study the bit-rock interaction model between the rock and the PDC bit, taking into account the impact of blade shape and cutter arrangement. They establish a dynamic model for a deep drilling system equipped with an arbitrary shape PDC bit and propose a stability prediction method. The results show that the shape of the blades and arrangement of the cutters on the PDC bit significantly affect the nonlinear vibration of the drilling system.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Bronislaw Czaplewski, Mateusz Bocian, John H. G. Macdonald
Summary: Despite two decades of study, there is currently no model that can quantitatively explain pedestrian-generated lateral forces. This research proposes a foot placement control law based on empirical data to calibrate and generalize the rigid-leg inverted pendulum model (IPM) for predicting lateral structural stability.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Ata Jafarzadeh, Peter D. Folkow, Anders Bostrom
Summary: This study investigates the scattering of elastic waves by an anisotropic sphere with orthorhombic symmetry inside an isotropic medium, and applies it to the characterization of polycrystalline materials with anisotropic grains. The expansion coefficients of the wave and displacement field are determined inside the sphere using recursion relations and boundary conditions. The T matrix elements are then obtained and used to analyze the attenuation and phase velocity of polycrystalline materials, particularly at low frequencies. The proposed approach shows good agreement with previous results and finite element method for strongly anisotropic materials.
Article
Acoustics
Shuling Gao, Rui Zhang, Zheng Fan, Ning Li, Yanan Yue, Lili Xie
Summary: In this study, a novel method is proposed to monitor fatigue damage in welded joints by computing the energy density in the diffuse ultrasonic signal. The results indicate that the correlation coefficient of the energy density exhibits a significant decreasing trend when crack initiation occurs, providing a unique signal to indicate crack initiation in welded joints.
Article
Acoustics
Jiahui Peng, Liang Wang, Bochen Wang, Minjuan Yuan, Wei Xu
Summary: A new path integration method is proposed for stochastic dynamical systems excited by Poisson white noise. It constructs an efficient one-step transition probability density function matrix based on a decoupling probability mapping. The method can handle multiple impulses occurring in a one-step transition time interval and considers the randomness of the impulse instant.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Yuhong Li, Zhida Ma, Peng Zhou, Siyang Zhong, Xin Zhang
Summary: In this study, we numerically investigate the aerodynamic and aeroacoustic performance of a hexacopter for urban air mobility. The results show that close placement of rotors leads to thrust fluctuations and increased sound pressure level. The presence of connecting arms generates additional noise, while the fuselage has little impact on total thrust and noise generation.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Longkai Zheng, Fengming Li, Zhijing Wu, Shurui Wen
Summary: A novel strategy is proposed for the dynamic modelling and quality factor evaluation of hemispherical shell resonators (HSR) considering the coupling of hemispherical shell and support rod. The artificial spring technique is introduced to simulate arbitrary boundary conditions. Hamilton's principle with the Rayleigh-Ritz method is employed to establish the equation of motion and obtain the natural frequencies of the HSR. The thermal energy method is applied to evaluate the thermoelastic damping (TED) of the HSR. The model of anchor loss is based on a separation and transfer method. The present theoretical model is validated through comparisons with published literature and finite element method (FEM). The effects of boundary conditions, geometrical parameters, and material properties on the vibration behaviors and quality factors of the HSR are analyzed.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
N. Aberkane-Gauthier, V. Romero-Garcia, D. Lecoq, M. Moleron, C. Lagarrigue, C. Pezerat
Summary: The dispersion and scattering properties of a soft solid plate with solid cylindrical inclusions embedded in it are investigated theoretically and numerically in this study. The system takes into account both the vibroacoustic coupling and the presence of viscoelastic losses. The presence of the inclusions introduces resonant and antiresonant phenomena, leading to an elastic band-gap and destructive modal interference in the soft solid plate.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Alexander N. Carr, Joel B. Lonzaga, Steven A. E. Miller
Summary: This study examines the effects of atmospheric boundary layer turbulence on the loudness variability of a sonic boom. The results show that the standard deviations of loudness metrics collapse across different convection levels of turbulence for small propagation distances. Additionally, the distribution of loudness metrics can be well approximated by a normal distribution for a given range of propagation distances and becomes increasingly skewed as distance increases.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
M. Amabili, H. R. Moghaddasi
Summary: Studies on nonlinear vibrations of circular cylindrical shells containing fluid have focused mostly on thin simply supported shells, leaving a lack of research on the behavior of thick cantilevered shells with shear and thickness deformations. This article presents, for the first time, models of thin and thick circular cylindrical shells with clamped-free boundary conditions based on the third-order shear deformation theory with thickness stretch. The derived governing differential equations describe the shell-fluid interaction. Results show that increasing the fluid level and decreasing the shell thickness in linear free vibration analysis significantly raise the fluid free-surface wave elevation, limiting the application of linear sloshing theory. The presence of the fluid changes the nonlinear behavior from softening to hardening, and intensifies the shell thickness deformation. Additionally, the contained liquid reduces the circumferential dynamic contraction caused by large amplitude vibrations.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Chaoyang Jiang, Danielle Moreau, Charitha de Silva, Con Doolan
Summary: This study numerically investigates the noise generation and flow characteristics of a forced-transitioned NACA 0012 airfoil with a micro-tube porous trailing edge. The results show that the micro tube structure reduces low-frequency trailing-edge noise and induces additional high-frequency noise through flow permeation. The interaction between flow permeation and boundary layer turbulence is the main cause for the noise reduction.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Mohammad Amin Faghihi, Hossein Mohammadi, Ehsan Azadi Yazdi, Mohammad Eghtesad, Shabnam Tashakori
Summary: This paper presents an integrated model to study the axial-torsional dynamics of a distributed drill string. By mathematical modeling, the characteristics of the drill string dynamics are explored. The findings contribute to improving drilling efficiency and reducing failures.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Zbynek Sika, Jan Krivosej, Tomas Vyhlidal
Summary: This paper presents a novel design of a compact six degrees of freedom active vibration absorber with six identical eigenfrequencies. The objective is to completely suppress the vibration of a machine structure with six motion components. By utilizing a Stewart platform structure equipped with six active legs, a spatial unifrequency absorber with six identical eigenfrequencies is achieved. The design is optimized using a correction feedback and active delayed resonator feedback.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Zhuogeng Zhang, Hongli Ji, Chongcong Tao, Jinhao Qiu, Li Cheng
Summary: This study introduces a new method to suppress panel flutter in supersonic flow using an add-on acoustic black hole (AABH). Numerical simulations demonstrate that the AABH effectively increases the critical flutter velocity and stabilizes the panel, reducing flutter amplitude.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Jiajia Zhang, Shan Yin, Bingyong Guo, Yang Liu
Summary: This paper presents a theoretical and experimental study on a universal vibro-impact system with bidirectional drift. The system exhibits various bifurcations and unpredictable motions under different excitation frequencies and amplitudes.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Viktor Hruska, Jean-Philippe Groby, Michal Bednarik
Summary: This study numerically and experimentally analyzes the amount and practical source of losses required for rectangular sonic black holes in air to effectively absorb low-frequency sound. The results show that in the presence of solely viscothermal losses, only high-order Fabry-Perrot resonances are likely to be critically coupled in realistic rectangular sonic black holes, resulting in absorption peaks that do not reach unity at low frequencies. To solve this issue, slits of rectangular sonic black holes are partially filled with porous materials, which significantly improves the absorption coefficient, especially at frequencies below the viscous/inertial transition frequency of the porous material.
JOURNAL OF SOUND AND VIBRATION
(2024)
