Article
Engineering, Ocean
Sang Woo Kim, Svein Saevik, Jie Wu, Bent Johan Leira
Summary: One of the major uncertainties in the prediction of Vortex-Induced Vibrations (VIV) is the simplification of real multi-directional current profiles into uni-directional ones. This study examines the correlation between a time domain model and experimental data on VIV, using both two-dimensional (2D) and three-dimensional (3D) currents. The results show that the time domain VIV model can accurately describe VIV in 2D and low velocity 3D currents, but underestimates VIV displacement in high velocity 3D currents. The study also highlights the importance of considering drag reduction in 3D current cases for accurate predictions.
APPLIED OCEAN RESEARCH
(2022)
Article
Engineering, Marine
Dingxin Leng, Di Liu, Haiyang Li, Bei Jin, Guijie Liu
Summary: This work investigates the effect of internal flow on the vortex-induced vibration characteristics of a marine riser under different boundary conditions. The results show that the increase in internal flow velocity and density has a negative influence on the vortex-induced vibration of the riser.
Article
Engineering, Ocean
Wude Xie, Weiyan Xin, Hongqiang Zhang
Summary: The study establishes a nonlinear dynamic model of a top-tensioned riser conveying varying density flow and simultaneously undergoing VIV, to analyze the influence of internal varying density flow on the vibrations and fatigue damage of the riser. The results show that the vibrations and fatigue damage of the riser are strongly affected when the internal fluid density fluctuates, with larger fatigue damage as the mean fluid density or the fluctuation amplitude of the internal varying fluid density increases.
APPLIED OCEAN RESEARCH
(2021)
Article
Engineering, Marine
Adeshina S. Adegoke, Akinfenwa Fashanu, Olayinka Adewumi, Ayowole Oyediran
Summary: This paper analyzes the nonlinear dynamic response of a single hybrid riser pipe to wave excitations. The detailed nonlinear equations of motion for the riser pipe are derived and solved using the method of multiple scale perturbation. The theoretical results show the coupling of longitudinal and transverse responses and the occurrence of primary and super-harmonic resonance excitations.
Article
Engineering, Marine
Qiurui Cai, Zhengnong Li, Ricky W. K. Chan, Han Luo, Guodi Duan, Bin Huang, Honghua Wu
Summary: This study investigated vortex-induced vibrations of marine risers in Ocean Thermal Energy Conversion systems. Flume experiments were conducted to measure the cross-flow acceleration of the riser at different current velocities and analyze the corresponding vibration responses. Numerical simulations based on the flume experiments were used for validation. The results demonstrated vortex-induced resonance in the first condition and observed similar vibration responses in the second condition, indicating the excitation of higher-order modes at higher flow velocities.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Engineering, Mechanical
Stanislas Le Guisquet, Marco Amabili
Summary: A procedure is presented to identify the nonlinear damping and stiffness parameters of harmonically forced continuous systems using a two-degree-of-freedom model, introducing cubic nonlinear damping and relying on the harmonic balance method with a three-harmonic expansion and genetic algorithm. The proposed novel cascade procedure includes a single term harmonic balance parameter estimation used as initiation of a minimization of the distance between data and a three-term harmonic balance model. These procedures are validated by parameter identification on synthetic and experimentally measured frequency-responses.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Engineering, Marine
Yunxu Shi, Zhe Wu, Wei Liu, Jin Wei
Summary: This paper presents a reduced-order analytical model for an L-shaped multi-beam structure with nonlinear joints to investigate nonlinear responses under three-to-one internal resonance conditions. The first two natural frequencies are calculated to determine the specific tip mass resulting in internal resonance. An approximation of the dynamic model solution is derived using the multi-scale method, showing the significant influence of nonlinear joint stiffness on the system's nonlinear response.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Acoustics
Bo Zhu, Xuanling Zhang, Tianyu Zhao
Summary: This study investigates the nonlinear vibrations of a viscoelastic fluid-conveying pipe under in-plane and out-of-plane transverse excitations, focusing on external and internal resonances. A three-dimensional pipe model is developed based on the Euler-Bernoulli beam theory and Kelvin-Voigt viscoelasticity to couple the in-plane and out-of-plane vibrations. The Galerkin method is used to solve the nonlinear governing equations, and the dynamical responses are examined in different regions. The results show complex nonlinear dynamics and provide insights for safe design and novel applications of such structures.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Mechanics
Yue Gao, Hongjun Zhu, Quanhua Li, Jie Hu, Tongming Zhou, Yongbo Shao
Summary: The nonlinear dynamic response of catenary flexible risers to ocean currents was studied through a series of experiments. It was found that the in-plane and out-of-plane responses were strongly influenced by the reduced velocity, with four different coupling patterns identified. Strong coupling was observed when the reduced velocity was high enough, while partial coupling was observed at lower velocities.
Article
Acoustics
M. V. Shitikova, V. V. Kandu, A. I. Krusser
Summary: In this paper, the dynamic response of a nonlinear Kirchhoff-Love plate resting on a viscoelastic foundation in a viscoelastic medium is studied using the generalized method of multiple time scales. The damping features of the foundation are described by the Kelvin-Voigt fractional derivative model. Equations are derived for both free oscillations and forced oscillations, allowing control of the damping properties by changing the parameters of fractionality. This expands the applicability of the solution.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Materials Science, Multidisciplinary
Wenan Jiang, Ye Li, Xindong Ma, Yong Wang, Liqun Chen, Qinsheng Bi
Summary: This paper explores a novel internal resonance method to scavenge flow energy from vortex-induced vibrations and confirms the mechanism of synchronous oscillations through an energy function. By proposing an electromagnetic energy harvester with one-to-one internal resonance, the capturing performance is demonstrated. Results show that the internal resonance scheme can enhance flow energy capture compared to the noninternal resonance case.
JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
(2022)
Article
Mechanics
Jin Wei, Tao Yu, Dongping Jin, Mei Liu, Yishen Tian, Dengqing Cao
Summary: This study introduces a two-degree-of-freedom model for a two-beam structure with nonlinear joints, investigating the nonlinear responses of the system to primary resonance of its first two modes under three-to-one internal resonance. By incorporating linear and nonlinear joint dynamic characteristics, the method of multiple scales is utilized to derive governing equations and approximate solutions for the nonlinear dynamical system. Comparisons are made with numerical integration method to analyze the nonlinear dynamic behavior in the structure.
ARCHIVE OF APPLIED MECHANICS
(2021)
Article
Engineering, Marine
X. P. Chang, C. J. Qu, Q. Song, Y. H. Li, J. Liu
Summary: This paper studies the frequency locking characteristics of a marine composite riser in cross-flow and inline directions under the combined action of internal and external ocean currents. The study finds that the internal flow velocity, external current velocity, fiber orientation angle, and top axial tension greatly influence the vibration stability and frequency locking characteristics of the riser.
Article
Engineering, Marine
Yuchao Yuan, Mengtian Zheng, Hongxiang Xue, Wenyong Tang
Summary: Steel catenary riser (SCR) is a popular choice for deepwater oil and gas exploitation in harsh marine environments. This study investigates the riser-seabed interaction (RSI) of an SCR with vortex-induced vibration (VIV) by integrating a mathematical model into a numerical riser model. Results show that VIV affects the trench development and safety of the SCR, and the coupling effect between RSI and VIV should be considered in full-scale SCR design.
Article
Materials Science, Multidisciplinary
T. S. Amer, M. A. Bek, S. S. Hassan, Sherif Elbendary
Summary: This article investigates the motion of a double nonlinear damped spring pendulum system with three degrees of freedom, using Lagrange's equations and multiple scales technique. The study categorizes resonance cases, examines steady-state solutions for stability, and analyzes nonlinear stability to identify stability and instability regions. The obtained high accuracy solutions have a significant impact on the system's dynamic behavior.
RESULTS IN PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Nouha Alcheikh, Hassen M. Ouakad, Sofiane Ben Mbarek, Mohammad Younis
Summary: This study experimentally and theoretically investigates mode crossing and mode veering in a V-shaped micro-beam under different excitation conditions. Analytical results based on a reduced-order model are compared with experimental data, showing good agreement. The effects of the micro-beam shape profile and length on the vibration behavior are discussed.
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
(2022)
Review
Engineering, Electrical & Electronic
Fahimullah Khan, Mohammad Younis
Summary: This paper reviews the recent developments of MEMS-based electrostatically actuated tunable capacitors, discussing different designs, tuning mechanisms, and performance parameters. It provides quantitative comparisons in terms of tuning range, Q factor, and electrodes configurations to assist in selecting designs that best suit various applications. The paper also highlights the importance of tunable capacitors in modern applications such as mobile communication, IoT, communication sensors, and 5G antennas.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Article
Engineering, Electrical & Electronic
AlHammam Niyazi, Qiu Xu, Fahimullah Khan, Mohammad Younis
Summary: A MEMS inertial switch with multiple, non-latching acceleration thresholds is proposed, which operates without consuming power in its inactive state. The switch utilizes a suspended proof mass and stationary electrodes placed at different positions to enable contact/actuation corresponding to the applied acceleration levels. It acts as an automatic switch or binary sensor for acceleration categorization.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Review
Engineering, Electrical & Electronic
Qiu Xu, Mohammad Younis
Summary: This paper presents a comprehensive review of recent advances in micromachined inertial switches/triggers, focusing on their advantages and disadvantages, sensitive directions, mechanisms of contact-enhancement, threshold accuracy, and tunability of the acceleration threshold. The paper also highlights various applications in healthcare, structural health monitoring, internet of things, and military, and discusses the latest research directions including multi-directions/axis, multi-threshold sensors, and machine learning implementation.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Article
Engineering, Electrical & Electronic
Fehmi Najar, Hassen M. Ouakad, Abdallah Ramini, Nouha Alcheikh, Mohammad Younis
Summary: In this work, we investigated the parametric resonances of an in-plane clamped-guided shallow arch microresonator analytically and experimentally. The experimental data and theoretical model showed that the second parametric resonance has a higher amplitude, indicating the great potential of the arch microresonator in sensing applications.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Review
Engineering, Electrical & Electronic
Sofiane Ben Mbarek, Nouha Alcheikh, Mohammad I. Younis
Summary: This paper provides an overview of the recent advances in MEMS-based infrared detectors, discussing the concepts, designs, and materials processing of IR MEMS thermopiles. The performance of IR MEMS detectors is examined and summarized based on findings from the past decade. The study concludes that the latest developments in MEMS technology and thermoelectric materials show great potential for improving the performance of IR thermopiles.
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2022)
Article
Multidisciplinary Sciences
Usman Yaqoob, Nizar Jaber, Nouha Alcheikh, Mohammad Younis
Summary: This work explores highly selective multiple analyte detection using a single MEMS device that exploits absorption and thermal conductivity mechanisms. By utilizing different vibration modes of a resonator, the device successfully detects relative humidity and helium gas selectively. This mode-dependent selective detection method is of great significance for the development of miniature, low-powered, and selective smart sensors.
SCIENTIFIC REPORTS
(2022)
Article
Multidisciplinary Sciences
Rodrigo T. Rocha, Mohammad Younis
Summary: This study presents a comprehensive investigation of the nonlinear saturation phenomenon on a compound micromachined structure. Experimental data and analytical simulations confirm the presence of internal resonance and saturation. The results are promising for further exploration and in-depth studies of compound structures and other systems.
SCIENTIFIC REPORTS
(2022)
Article
Engineering, Electrical & Electronic
Wen Zhao, Fahimullah Khan, Nouha Alcheikh, Mohammad Younis
Summary: This paper presents a multi-mode excitation technique to amplify the amplitude signal of micro-resonators-based sensors operating at their higher-order modes. The results show that multi-mode excitation can reduce noise effects, elevate the dynamic response level, and amplify the total amplitude response. The efficiency of this technique is demonstrated through enhancing the performance of a gas sensor detecting Helium at the 2nd mode with a 24-times amplitude magnification.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Usman Yaqoob, Wagner B. Lenz, Nouha Alcheikh, Nizar Jaber, Mohammad Younis
Summary: This study proposes a highly selective multiple gases detection system using an electro-thermally heated silicon micro-resonator and machine-learning algorithms. By conducting principal component analysis and training algorithms, the proposed gas-sensing approach achieves high classification accuracy, making it promising for intelligent and highly selective compact size sensing platforms.
IEEE SENSORS JOURNAL
(2022)
Article
Physics, Applied
Wen Zhao, Nouha Alcheikh, Sofiane Ben Mbarek, Mohammad I. Younis
Summary: In this study, a highly sensitive multi-parameter sensor for magnetic and gas detection is presented. The device utilizes an in-plane doubly clamped micro-beam micro-resonator that is electrothermally heated. It demonstrates high sensitivity and good linearity for both magnetic and gas detection, specifically for carbon dioxide and methane. The sensor also enables simultaneous detection of magnetic fields and gas by tracking the frequency shift of symmetric and anti-symmetric modes.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Engineering, Mechanical
Hamed Farokhi, Rodrigo T. Rocha, Amal Z. Hajjaj, Mohammad Younis
Summary: This study presents a thorough investigation on the nonlinear damping of in-plane micromachined electromechanical resonators. The experimental and theoretical analysis reveals the strong nonlinear damping characteristics of the microresonator, and proposes calibration methods for the nonlinear damping models.
NONLINEAR DYNAMICS
(2023)
Article
Automation & Control Systems
Qiu Xu, Lvjun Wang, Mohammad Younis
Summary: In this article, an inertial switch with three threshold levels is presented, which enables quantitative acceleration measurements and detection of acceleration direction in the x-y plane. The switch consists of four movable electrodes and twelve flexible stationary electrodes. Activation of individual electrical switches determines the direction of acceleration. Simulation and experimental results show that increasing the number of electrical switches improves the accuracy and resolution of acceleration direction detection.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Automation & Control Systems
Qiu Xu, Raed Alahmdi, Lvjun Wang, Rodrigo T. Rocha, Mohammad I. Younis
Summary: In this article, a multithreshold microelectromechanical tunable inertial switch is introduced, aiming to provide quantitative information on acceleration while being energy-saving. The device is composed of serpentine springs, a suspended proof mass, and stationary electrodes, allowing for measurement of acceleration in different ranges. Experimental and simulation results validate the reliability and effectiveness of the device concept.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Wagner B. Lenz, Usman Yaqoob, Rodrigo T. Rocha, Mohammad Younis
Summary: This study demonstrates the identification of multiple gases using a heated MEMS resonator and machine learning. By measuring the cooling/heating effect of injected gases on the micro beam, the gases, including acetone and helium, can be accurately classified and their concentration levels determined using machine learning algorithms and Principal Component Analysis.
Article
Mechanics
E. Mubai, D. P. Mason
Summary: The two-dimensional turbulent thermal classical far wake is investigated in this study. The turbulence is described using the Boussinesq hypothesis for Reynolds stresses and Prandtl's mixing length model for eddy viscosity and eddy thermal conductivity. Two conservation laws are derived for the thermal boundary layer equations using the multiplier method, and two conserved quantities are obtained from the conserved vectors and boundary conditions. Lie point symmetry associated with the momentum and thermal conserved vectors is derived, showing that the momentum and thermal mixing lengths are proportional. An invariant solution is obtained numerically using a shooting method, and analytically when v = 0, kappa = 0.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Daniel J. Arrigo, Travis C. Chism
Summary: This paper investigates the governing equations for plane stress deformations of isotropic incompressible hyperelastic materials. The authors previously discovered a linearization method for the plane strain case of the Varga material, and in this paper, they further demonstrate that the governing equations for the plane stress case can also be linearized.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
A. P. Chugainova, R. R. Polekhina
Summary: This article numerically investigates the conditions for the decay of a nonlinear wave into a system of waves traveling at different velocities in a viscoelastic weakly anisotropic medium. Solutions of a hyperbolic system of equations are studied in the region of nonuniqueness of parameters, where a solution to the Riemann problem can be constructed with both a single wave and a system of waves corresponding to the same initial data.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Yu. N. Grigoriev, E. I. Kaptsov, S. V. Meleshko
Summary: This paper studies the mathematical properties of gasdynamics equations with thermochemical nonequilibrium and provides solutions for two different models. The results show that the solutions to the modified system of equations are physically consistent and can describe the effects of thermochemical nonequilibrium.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Y. Hao, X. Y. Guo, Y. B. Fu
Summary: This paper investigates the nonlinear stochastic dynamic response of a three-degree-of-freedom(3-DOF) airfoil with high substructural nonlinearity under vertical turbulent disturbances. The effects of parameters such as the incoming velocity, turbulence scale and intensity on the stochastic dynamics behavior of the system are clarified.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
T. Flament, J. -F. Deu, A. Placzek, M. Balmaseda, D. -M. Tran
Summary: This paper focuses on the numerical computation of vibrations in geometrically nonlinear structures induced by aeroelastic coupling with fluid flow using reduced order models (ROM). The proposed ROM formulation utilizes projection on a basis of reduced dimension enhanced with dual modes, allowing for the accurate capture of dynamic characteristics and adaptation to unsteady aerodynamic loads. The limitations of the classical Implicit Condensation method are highlighted, while the ROM proposed overcomes these limitations and accurately captures the dynamics.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Sidhartha Sankar Roy, Kishore Chandra Biswal
Summary: This study investigates the non-linear slosh dynamics of a sloped wall tank with a bottom-mounted object under seismic excitation. The potential flow theory is used to model the liquid domain using a mixed Eulerian-Lagrangian method. The study successfully quantifies the non-linear seismic response of the tank and the influence of the internal object on the hydrodynamic behavior. A parametric investigation is conducted by altering the object's height. Comparison with linear analysis justifies the necessity of non-linear analysis. The developed non-linear finite element model is found to be more effective and can be used in designing structure-coupled sloped wall TLDs.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Kapil Dev, Om P. Suthar
Summary: This study presents stability analyses of thermosolutal convection in a Newtonian fluid-saturated Darcy porous layer under non-uniform inclined heating, considering the presence of the Soret effect. The results reveal the destabilizing effect of the solutal Darcy-Rayleigh number and Lewis number on the system's stability, while the Soret parameter has a non-monotonic effect depending on the horizontal Rayleigh number.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Sandhya Maurya, Dia Zeidan, Manoj Pandey
Summary: This paper investigates a two-phase mass flow model governed by gravity, which involves solid particles and a viscous fluid. By utilizing the Lie symmetries admitted by the system, similarity solutions for the (2+1)-dimensional two-phase mass flow model are obtained. Through analytical solutions and numerical analysis, the physical behaviors of the resulting systems are successfully analyzed.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Longfei Tan, Wei Zhang, Zixun Wang, Bowen Hou, Wei Sun
Summary: This study investigates the factors influencing the stiffness variation characteristics of a bolted joint during service, including macro deviation, micro-topography, and hysteresis characteristics. Through experiments and finite element modeling analysis, it is found that macro deviations and micro-topography on the bearing surface can cause irregular dynamic changes in the stiffness of the bolted joint, significantly affecting the dynamic/static response of the entire structure.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
Article
Mechanics
Yu Xiao, Ze-Qi Lu, Nan Wu
Summary: This study investigates the characteristics of a magnet-engaged nonlinear piezoelectric energy generator stimulated by friction-induced vibration (FIV) in two distinct design configurations (in parallel and in-series). The results indicate that factors such as decay factor, dynamic friction coefficient, static friction coefficient, and normal force have an effect on the stability of the system and the generation of FIV. The in-parallel systems exhibit a higher charging power within the same operating range, while the in-series systems are more likely to excite FIV with a wider operating range.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2024)
