Article
Mechanics
Habib Ahmadi, Aliakbar Bayat, Nguyen Dinh Duc
Summary: This study investigates the non-linear vibrations of stiffened imperfect functionally graded double-curved shallow shells, as rested on nonlinear elastic foundations. The shells are exposed to external harmonic excitation and thermal situations. The modeling of shells is derived according to the classical shell theory and the non-linear geometric von Karman relationships, considering material properties changes along the thickness direction based on a power law index. The study uses analytical and numerical methods to analyze the resonance behavior and nonlinear dynamic behaviors of the shells under various conditions.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Mechanical
Tianjun Yu, Yong Cheng, Sha Zhou
Summary: A novel autoparametric modulated periodic structure utilizing asymmetric architecture of nonlinear chiral microstructures is proposed and analyzed for its non-reciprocal wave behavior and band topology through numerical calculations. The structure may serve as a building block for realizing one-way propagation and mechanical logic gate.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Astronomy & Astrophysics
Yonadav Barry Ginat
Summary: This paper discusses the consideration of small-scale inhomogeneities in modeling the universe on a cosmic scale, introducing a multiple-scales method based on singular perturbation theory and deriving an effective Einstein equation. Conditions are established to ensure that deviations from the large-scale space-time metric do not grow unboundedly, and it is shown that these conditions are satisfied in the case of non-relativistic matter.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Engineering, Mechanical
Ting Tan, Zhemin Wang, Liang Zhang, Wei-Hsin Liao, Zhimiao Yan
Summary: A new autoparametric vibration energy harvester coupled by a nonlinear energy sink is proposed to extend the working bandwidth for piezoelectric vibration energy harvesting. The study demonstrates that increasing the stiffness and damping of the nonlinear energy sink enhances the average power of the lower boundary of the harvesting band, while increasing the mass of the energy sink and substructural natural frequency ratio improves the average power of the upper boundary. The proposed harvester shows a significant 200% increase in maximum average power compared to a system without the nonlinear energy sink, providing a method for stable broadband vibration energy harvesting with chaos control.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Engineering, Mechanical
Wei Liu, Zhongguo Guan, Shichun Zhang, Yuchun Li
Summary: In this paper, a novel method called the dynamic axial force transfer coefficient (DTC) method is proposed to investigate the spatial dynamic instability characteristics of complex frame structures. The proposed method, in conjunction with the harmonic balance method and the finite element method (FEM), can accurately determine the unstable boundary of multi-system frame structures and predict the strong coupling effect of practical structures.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Mechanics
N. A. Saeed, G. M. Moatimid, F. M. F. Elsabaa, Y. Y. Ellabban
Summary: This work investigates the nonlinear transversal oscillations of a cantilever beam system at various resonance cases and proposes a time-delayed position-velocity controller to suppress the vibrations. The controlled nonlinear model is analyzed using the multiple scales homotopy approach, and the amplitude-phase modulating equations governing the system dynamics at different resonance cases are extracted. The study explores the influence of different controller parameters on the system vibration behaviors and demonstrates the significant impact of loop-delay on the controller efficiency.
ARCHIVE OF APPLIED MECHANICS
(2021)
Article
Mechanics
Chandan Kumar, Akshay Prakash
Summary: Nonlinear interaction among resonance waves in a high-speed boundary layer, where a wave triad is composed of second mode waves, has been observed. With an increase in Mach number, disturbances shift towards the boundary layer edge, and a significant increase in amplification factor due to wave interaction has been observed.
Article
Meteorology & Atmospheric Sciences
Qiuyan Zhang, Yang Zhang, Zhaohua Wu
Summary: Using the ensemble empirical mode decomposition method, this study investigates the multiple timescales of the southern annular mode (SAM) and identifies the importance of longer-timescale variabilities, especially the cross-seasonal variability, for the persistence of SAM. The study also shows that the cross-seasonal variability of SAM is associated with extratropical air-sea interaction.
Article
Engineering, Civil
Hai-En Du, Li-Juan Li, Guo-Kang Er, Vai Pan Iu
Summary: In this paper, the constrained parameter-splitting-multiple-scales (C-PSMS) method is used to obtain approximate analytical solutions for the primary and 1/3 sub-harmonic resonances of a cantilever-type energy harvester. The C-PSMS method combines multiple-scales (MS) method with the harmonic balance (HB) method. Accurate stability results are obtained, unlike the erroneous stability results obtained using the Floquet theory and classical HB method. The C-PSMS method gives improved results compared to the Floquet theory and HB method.
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(2023)
Article
Automation & Control Systems
Miguel Picallo, Saverio Bolognani, Florian Dorfler
Summary: A classical approach to design controllers for interconnected systems is to assume different time scales for each subsystem. In this work, we propose an alternative approach by adding a feed-forward term to modify the dynamics of faster systems to anticipate slower ones. We provide examples in bilevel optimization and cascade control design, where our approach improves the performance of existing methods.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Engineering, Electrical & Electronic
Lijia Zhang, Cao Xia, Jiayang Chen, Wei Zhang, Jiajia Xiang, Dong F. Wang, Zhuqing Wang
Summary: An ultrasensitive mass detection scheme is proposed via the frequency superposition phenomena of AVSs. This work not only opens a new avenue for applications of AVSs but also provides a new metrological scheme for mass sensitivity amplification.
IEEE SENSORS JOURNAL
(2023)
Article
Computer Science, Interdisciplinary Applications
Ji-Huan He, Man-Li Jiao, Khaled A. Gepreel, Yasir Khan
Summary: This paper reveals the effectiveness of the homotopy perturbation method for strongly nonlinear oscillators. A generalized Duffing oscillator is adopted to illustrate the solving process step by step. A nonlinear frequency-amplitude relationship with a relative error of 0.91% is obtained, and the solution morphology is discussed along with the improvement of accuracy.
MATHEMATICS AND COMPUTERS IN SIMULATION
(2023)
Article
Mathematics, Applied
Xiaochun Nie, Ting Tan, Zhimiao Yan, Zhitao Yan, Lingzhi Wang
Summary: The piezoelectric vibration energy harvester based on 1:2 internal resonance has the advantages of wide-band and high-efficiency energy harvesting. The method of equivalent forced load is proposed to decouple the voltage frequency and improve the accuracy of the output response. The amplitude-frequency response curve exhibits nonlinear hardening and softening in the whole excitation frequency range.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Mechanics
Yuji Harata, Takashi Ikeda
Summary: This study aims to investigate the reason behind the localization of harmonic oscillations in a system of nonlinear pendulums connected by linear torsion springs and subjected to sinusoidal displacement excitation in the horizontal direction. The modal analysis and Van der Pol's method are used to derive the frequency response curves (FRCs) of the harmonic oscillations. The effects of array imperfection on the FRCs are also briefly discussed.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2023)
Article
Engineering, Mechanical
Steven W. Shaw, Sahar Rosenberg, Oriel Shoshani
Summary: Models for nonlinear vibrations often use polynomial terms to simulate nonlinear phenomena. The analysis of symmetric systems with cubic stiffness terms is common, and the inclusion of asymmetric quadratic terms is known to modify the effect of cubic nonlinearity in weakly nonlinear systems. However, in many cases, a monotonic dependence is not observed, requiring the use of techniques for strongly nonlinear systems or higher-order terms and perturbation methods.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Civil
M. Shabdin, Nader Khajeh Ahmad Attari, M. Zargaran
Summary: This study conducted in-plane cyclic tests on unreinforced brick masonry walls and found that the proposed technique of strengthening the boundaries on both sides significantly improved the behavior of the retrofitted walls.
JOURNAL OF EARTHQUAKE ENGINEERING
(2021)
Article
Engineering, Civil
Zakariya Waezi, Nader K. A. Attari, Fayaz R. Rofooei
Summary: This paper investigates the effectiveness of using nonlinear fluid/structure interaction to control the seismic response of structures under near-field earthquakes. The dynamic response of a SDOF structure equipped with a circular cylindrical liquid tank is studied, focusing on the resonance between the first unsymmetrical sloshing mode and the SDOF structural mode. The results show that the appended liquid tanks can effectively reduce the dynamic response of the structural system under pulse-like earthquakes.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2022)
Article
Engineering, Civil
Saheb Ali Asadzadeh, Majid Mohammadi, Nader K. A. Attari, Seyed Alireza Zareei
Summary: This study investigates the effect of wall-to-frame connectors on the behavior of steel frames infilled with autoclave-cured aerated concrete walls. The results show that V-shaped and T-shaped connectors can maintain the stability of the wall and keep it intact after 2.5% in-plane drift.
JOURNAL OF EARTHQUAKE ENGINEERING
(2022)
Article
Engineering, Civil
Nahid Attarchian, Nader K. A. Attari, Zakariya Waezi
Summary: This study investigates the seismic behavior of rectangular reinforced concrete columns under pure flexure, pure torsion, and combined flexural-torsional loadings. The results show that under combined loading, the displacement capacity and moment capacity of the specimens decrease, compared to the pure-flexural case. An equation expressing the interaction between flexural and torsional moment strength capacity is proposed.
JOURNAL OF EARTHQUAKE ENGINEERING
(2022)
Article
Engineering, Civil
Zakariya Waezi, M. Javad Hashemi
Summary: This paper presents a novel method for stochastic simulation of the vertical components of near-field pulse-less earthquakes and verifies its effectiveness through simulating multiple different scenarios. The results show that the method can generate vertical earthquake records that are consistent with actual situations.
JOURNAL OF EARTHQUAKE ENGINEERING
(2022)
Article
Engineering, Civil
Amir Shahsahebi, Zakariya Waezi, M. Javad Hashemi
Article
Construction & Building Technology
M. Shabdin, M. Zargaran, Nader K. A. Attari
Summary: A new analytical model is proposed in this paper to evaluate the in-plane shear capacity of strengthened clay brick masonry walls using textile reinforced mortar, with accuracy calibrated with experimental data. Major parameters considered in the experimental investigations include the thickness of masonry wall, the thickness of reinforcement layer, the number of reinforcement layers, reinforcement configuration, and the type of textile reinforcements. The presented analytical model demonstrates a reasonable agreement with the experimental results.
MATERIALS AND STRUCTURES
(2021)
Article
Engineering, Civil
Sara Balzadeh, Zakariya Waezi
Summary: This study investigated the design parameters and efficiency of Arc-Surfaced Friction Dampers (ASFD) in seismic events. Results showed that implementing ASFD as a control device significantly reduced the collapse speed of structures compared to uncontrolled structures.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2022)
Article
Engineering, Civil
Mojdeh Zargaran, Nader K. A. Attari, Saeid Alizadeh
Summary: The flexural behavior of textile reinforced concrete (TRC) samples reinforced with different types of textile has been studied. It was found that increasing the number of fabric layers improves the flexural strength of TRC samples, while reducing the fabric mesh size enhances the bending strength of Aramid TRC samples.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2023)
Article
Engineering, Civil
Nader K. A. Attari, Zakariya Waezi, Kian Khalili Jahromi, Mohammadreza Bayat
Summary: Mechanical supports are crucial for the functionality of buildings, as they greatly impact the quality, durability, and performance of piping or ductwork, especially during earthquakes. This study investigates the structural performance of common mechanical supports with different sections when subjected to various shaking table tests. The experimental findings suggest that the prescribed equipment-to-structure acceleration ratio is generally too conservative except in cases of failure. Additionally, the dependence of the equipment-to-structure acceleration ratio is significantly higher in the perpendicular direction to the pipeline's orientation, emphasizing the need for its consideration in the design process. Moreover, the results demonstrate that the support system generally retains its stiffness and strength through re-locking after a failure in the connection due to sliding.
Article
Acoustics
Milad Amini, Zakariya Waezi, Mohammad Manthouri
Summary: This paper investigates the use of ATMD and VFOFPID controller to improve the performance of building structures during earthquakes. The results show that this controller can effectively reduce the displacement and absolute acceleration of the structures.
JOURNAL OF VIBRATION AND CONTROL
(2023)
Article
Engineering, Multidisciplinary
Z. Waezi, M. A. Raoof
Summary: This paper presents a semi-analytic procedure for deriving response spectrum of synthetic acceleration records generated using the Double-Frequency Model (DFM). The proposed method shows good accuracy in estimating elastic response of structures, especially in short-period ranges. Comparisons with previous models and approximations demonstrate the effectiveness of the semi-analytic model.
