Article
Engineering, Aerospace
Lokanna Hoskoti, Shakti S. Gupta, Mahesh M. Sucheendran
Summary: A linear geometric stiffening model is developed for a rotating beam undergoing coupled motion. The model describes the deformation of the beam using different coordinate systems and derives the kinetic and strain energy expressions. The equations of motion are derived using Lagrange's equations and dimensionless parameters are identified. A complex modal analysis method is used to determine the modal characteristics and the results are verified with existing literature and finite element method. The effect of dimensionless parameters on the modal characteristics is studied.
Article
Mechanics
Slavisa Salinic, Aleksandar Obradovic, Aleksandar Tomovic, Dragan Trifkovic, Aleksandar Grbovic
Summary: The paper investigates the coupled axial-bending vibration problem of an axially functionally graded Timoshenko cantilever beam with non-uniform cross-section. The coupling phenomenon arises from the transverse eccentricity of the mass center of a rigid body attached to the beam's free end. An approach based on the symbolic-numeric method of initial parameters is proposed to study the coupling phenomenon. The influence of transverse eccentricity on the natural frequencies and mode shapes of the cantilever beam is examined. This approach also has the potential to be applied to vibration problems of systems composed of rigid bodies interconnected by non-uniform non-homogeneous beams.
Article
Mechanics
Zhu Su, Xingxing Xiong
Summary: In this paper, a nonlinear dynamic model is established for rotating beams with elastic boundary, considering factors such as pre-twisted, setting angle, thermal gradient, and geometric nonlinearity. The linear part of the model is solved using a modified Fourier series method to determine the modal function with elastic boundary. The nonlinear dynamic equations of a rotating pre-twisted beam with elastic boundary are obtained using the modal expansion of the displacements and Lagrange equation. The multi-scale method is then employed to solve the nonlinear problem and study the vibration response of the rotating beam with elastic constraints.
Article
Engineering, Mechanical
Qihang Li, Can Chen, Shuai Gao, Yinglin Ren, Weimin Wang
Summary: This paper investigates the nonlinear coupling between bending and torsional vibrations in rotor systems and proposes a method to improve the efficiency of transient numerical simulation. Through numerical simulations and experimental validation, it is found that torsional excitation generates sideband frequency components in CBT models and the effect of gravity is significant.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Mechanics
Hesheng Han, Dengqing Cao, Lun Liu, Jingbo Gao, Youxia Li
Summary: The free vibration of rotating bending-torsional composite Timoshenko beams is analyzed with consideration of composite material coupled rigidity, Coriolis effects and the separation of the cross-section's mass and shear centers. A new method, differential transform matrix method (DTMM), is proposed to deal with the governing matrix equation. The study investigates mode shapes, natural frequencies, and dynamic characteristics of the rotating CTB beams, with the results consistent with literature and COMSOL calculations. The influences of composite material rigidity, rotation speed, hub radius, and axial load on natural frequencies and mode shapes are studied, observing frequency veering and mode shift phenomena, as well as determining the beam's critical buckling loads corresponding to axial load.
Article
Energy & Fuels
Amna Algolfat, Weizhuo Wang, Alhussein Albarbar
Summary: This study investigates the influence of centrifugal stiffening on the free vibrations and dynamic response of offshore wind turbine blades. The results demonstrate that the angular speed directly affects the modal features, which directly impacts the dynamic response.
Article
Engineering, Civil
Zijian Yang, Wenbing Wu, Hao Liu, Yunpeng Zhang, Rongzhu Liang
Summary: A coupled vibration model of unsaturated soil-pile system under Rayleigh waves was established, and the dynamic response of the pile body was analyzed. The results of this study are of great significance for the seismic design of pile foundations under Rayleigh waves.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2023)
Article
Mechanics
Ufuk Gul, Metin Aydogdu
Summary: In this study, a micro-nano-scale Timoshenko-Ehrenfest beam model was analyzed using doublet mechanics theory, with governing equations and boundary conditions obtained. The static bending, buckling, and vibration problems of Timoshenko microbeams were examined in detail, and the results were compared to other classical and non-classical continuum theories. The influence of thickness to length scale parameter ratio and slenderness ratio on the static bending, buckling, and vibration problems were investigated to demonstrate the doublet mechanics model.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2021)
Article
Construction & Building Technology
Sourav Das, M. Mohamed Sajeer, Arunasis Chakraborty, Saptarshi Sarkar
Summary: This study aims to reduce the deformation of large horizontal axis wind turbine blades using SMA-based centrifugal stiffening, with a developed discrete model demonstrating the proposed strategy's performance. Numerical results clearly show the significance of the proposed SMA-based stiffening in reducing blade vibration, with sensitivity analysis showcasing its performance over the operational range. The study highlights performance enhancement in terms of deformation and design, ultimately improving the serviceability of the blade.
STRUCTURAL CONTROL & HEALTH MONITORING
(2021)
Article
Mechanics
Hedi Hamdi, Adel Hamdi, Rachid Nasri
Summary: This paper presents a simplex finite element model for studying the dynamics of rotating cantilever beams subjected to distributed external loads. The model combines the finite element method and Timoshenko's beam theory, and uses Euler's three-angle sequence to parameterize the 3D motion of the beam. The results show that the dynamic centrifugal effect decreases the natural frequencies of the beam, and the gyroscopic coupling induces rapid extension and torsion beatings when the beam undergoes a step bending load.
MECHANICS RESEARCH COMMUNICATIONS
(2023)
Article
Engineering, Multidisciplinary
Y. X. Hao, Y. Y. Liu, W. Zhang, L. T. Liu, K. C. Sun, S. W. Yang
Summary: This paper investigates the natural vibrations of a variable thickness cantilever twisted plate made of metal porous material. Using classical thin shell theory, the first and second fundamental forms of a surface, and von Karman geometric relationship, the total potential energy and kinetic energy of the cantilever twisted plate are derived. The dynamic system is then reduced to an eigenvalue problem using the Rayleigh-Ritz procedure. Numerical simulations are conducted to obtain frequency curves and mode shapes, revealing the internal connection between natural vibration and the parameters.
DEFENCE TECHNOLOGY
(2023)
Article
Construction & Building Technology
Hao Luo, Zhiyang Cao, Xun Zhang, Cong Li, Derui Kong
Summary: Due to the complex structure and limitations of classical SEA, a combined SEA approach is used to study the dynamic response of a steel box girder. The results show that indirect coupling caused by the periodicity of the structure has a significant impact on high-frequency vibrations. This study is important for understanding the dynamic response of steel box girders and provides guidance for vibration and noise control.
STEEL AND COMPOSITE STRUCTURES
(2022)
Article
Mechanics
Jiang Xu, Zhichun Yang, Jie Yang, Yinghui Li
Summary: This paper investigates the influence of boundary relaxation on the free vibration characteristics of a rotating composite laminated Timoshenko beam. Artificial springs are used to simulate the relaxed boundary conditions, adjusting the stiffness of the springs to obtain various relaxation conditions, with relaxation parameters introduced to evaluate the extent of boundary relaxation.
COMPOSITE STRUCTURES
(2021)
Article
Mechanics
Souvik Singh Rathore, Vishesh Ranjan Kar, Sanjay Sanjay
Summary: The nonlinear frequency responses of functionally graded (ceramic/metal/ceramic) straight/curved blade-type structures are investigated considering rotation and thermal effects. Geometrical nonlinearity is incorporated using Green-Lagrange's strain and higher-order shear deformation theory. The constituent materials are temperature-dependent, and the overall material properties are evaluated using Voigt's homogenization scheme with a modified power-law function. The linear and nonlinear frequency responses are computed using a nonlinear finite element method and Picard's successive iteration scheme, considering various geometric and material parameters.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Acoustics
G. Deepak Kumar, B. Panigrahi
Summary: The dynamic attributes of rotating cracked tapered cantilever functionally graded material (FGM) beams are investigated using energy method. Nonlinear governing equations are generated and solved using an iterative algorithm. The effects of crack location and depth on the nonlinear frequency ratios are studied.
JOURNAL OF VIBRATION AND CONTROL
(2023)
Article
Acoustics
Sandip Chajjed, Mohammad Khalil, Dominique Poirel, Chris Pettit, Abhijit Sarkar
Summary: This paper reports the generalization of the Bayesian formulation of the flutter margin method, which improves the predictive performance by incorporating the joint prior of aeroelastic modal parameters. The improved algorithm reduces uncertainties in predicting flutter speed and can cut cost by reducing the number of flight tests.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Pascal Zeise, Bernhard Schweizer
Summary: Air ring bearings are an improved version of classical air bearings, providing better damping behavior and allowing operation above the linear threshold speed of instability. However, there is a risk of dangerous vibrations in certain rotor systems, which can be addressed by considering ring tilting effects.
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
Kai Li, Yufeng Liu, Yuntong Dai, Yong Yu
Summary: This paper presents a novel light-powered self-oscillating liquid crystal elastomer (LCE) bow that can self-oscillate continuously and periodically under steady illumination. The dynamics of the LCE bow are theoretically investigated and numerical calculations predict its motion regimes. The suggested LCE bow offers potential advantages in terms of simple structure, customizable size, flexible regulation, and easy assembly.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Carmelo Rosario Vindigni, Giuseppe Mantegna, Calogero Orlando, Andrea Alaimo
Summary: In this study, a simple adaptive flutter suppression system is designed to increase the operative speed range of a wing-aileron aeroelastic plant. The system achieves almost strictly passivity by using a parallel feed-forward compensator implementation and the controller parameters are optimized using a population decline swarm optimization algorithm. Numerical simulations prove the effectiveness of the proposed simple adaptive flutter suppression architecture in different flight scenarios.
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
Shahram Hadian Jazi, Mostafa Hadian, Keivan Torabi
Summary: Non-uniformity and damage are the main focus in studying vibrations of beam elements. An exact closed-form explicit solution for the transverse displacement of a nonuniform multi-cracked beam is introduced using generalized functions and distributional derivative concepts. By introducing non-dimensional parameters, the motion equation and its closed-form solution are obtained based on four fundamental functions. The impact of crack count, location, intensity, and boundary conditions on natural frequency and mode shape is evaluated through numerical study.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Acoustics
Eugenio Tramacere, Marius Pakstys, Renato Galluzzi, Nicola Amati, Andrea Tonoli, Torbjoern A. Lembke
Summary: This paper proposes the experimental stabilization of electrodynamic maglev systems by means of passive components, providing key technological support for the Hyperloop concept of high-speed and sustainable transportation.
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
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
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
Guanfu Lin, Zhong-Rong Lu, Jike Liu, Li Wang
Summary: Vision-based measurement is an emerging method that enables full-field measurement with non-contact and high spatial resolution capabilities. This paper presents a single-camera method for measuring out-of-plane vibration of plate structures using motion-parametric homography to capture image variation and displacement response.
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
Justine Carpentier, Jean-Hugh Thomas, Charles Pezerat
Summary: This paper proposes an improved method for the identification of vibration sources on a car window using the corrected force analysis technique. By redefining inverse methods in polar coordinates, more accurate results can be obtained.
JOURNAL OF SOUND AND VIBRATION
(2024)