Qifa Lang, Yuqiao Zheng^*, Tiancai Cui, Chenglong Shi, Heyu Zhang

Energy Engineering, Vol.121, No.2, pp. 483-498, 2024, DOI:10.32604/ee.2023.042437

Abstract This work presents a novel approach to achieve nonlinear vibration response based on the Hamilton principle. We chose the 5-MW reference wind turbine which was established by the National Renewable Energy Laboratory (NREL), to research the effects of the nonlinear flap-wise vibration characteristics. The turbine wheel is simplified by treating the blade of a wind turbine as an Euler-Bernoulli beam, and the nonlinear flap-wise vibration characteristics of the wind turbine blades are discussed based on the simplification first. Then, the blade’s large-deflection flap-wise vibration governing equation is established by considering the nonlinear term involving the centrifugal force. Lastly, it is… More >

Ayumi Takahashi^1,*, Kenya Kashiwagi², Tomoyuki Tsuchiya², Kazuhito Misaji¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.24, No.1, pp. 1-1, 2022, DOI:10.32604/icces.2022.08705

Abstract As a characteristic of seismic isolated laminated rubber, the rubber is torsional deformed when it was loaded in horizontal bi-direction, and breaks with less force than when loaded in unidirectional. It is necessary to extend the model which has been used for unidirectional analysis to the model which can be analyzed in bi-direction. As a previous study, Igarashi applied the Multiple Shear Springs (MSS) model which is a horizontal bi-directional model, and compared them with measured values to verify their validity [1]. The authors extended PFT-ELS method to MSS model which can analyze bidirection [2]. The ELS method is a… More >

Ayumi Takahashi^1,*, Tomoyuki Tsuchiya², Keiichi Motoyama³, Kazuhito Misaji¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.23, No.1, pp. 15-15, 2021, DOI:10.32604/icces.2021.08354

Abstract The seismic-isolation laminated rubber is used as a means of suppressing damage to the structures caused by an earthquake. To design the seismically isolated structure, it is important to calculate the dynamic response reflecting the rubbers characteristics accurately. The authors have applied the nonlinear vibration analysis method using the restoring force model of the power function type to the seismic response analysis of seismic isolation rubber in horizontal unidirectional [1-3]. However, when seismic isolation laminated rubber is loaded in horizontal bi-direction, the seismic isolation laminated rubber is torsional deformed and breaks with less force than when loaded in unidirectional. It… More >

S. Sivakumar^1,*, L. Jayakumar²

Sound & Vibration, Vol.53, No.6, pp. 277-296, 2019, DOI:10.32604/sv.2019.08099

Abstract This paper elaborates a nonlinear fluidic low frequency vibration isolator designed with the characteristics of quasi-zero stiffness (QZS). The existing model of QZS vibration isolator enhances amplitude of vibration and attenuating vibration frequencies. This concern with displacement plays a vital role in the performance and instability of oblique spring setup reduces the isolator performance in horizontal non-nominal loads, in this accordance; this paper associates double acting hydraulic cylinder (fluidic actuators in short) in oblique and helical coil spring. An approximate expression of unique analytical relationship between the stiffness of vertical spring and bulk modulus of the fluid is derived for… More >

T-P. Chang¹, M-F. Liu²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.1, pp. 35-40, 2008, DOI:10.3970/icces.2008.005.035

Abstract In the present study, we perform the non-linear vibration analysis of an elastic plate subjected to weak fluid loading in an inclined magnetic field. The structural nonlinearity, fluid nonlinearity, and the effects of magnetic field are all incorporated in the formulations to derive the governing equation of the plate. The method of multiple scales is adopted to determine the eigenvalues and mode shapes of the linear vibration, and then the amplitude of the nonlinear vibration response of the plate is calculated. Based on the assumptions of ordering and formulations of multiple scales, it can be concluded that the non-linear dynamics… More >

S. Lentzen¹, R. Schmidt¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 201-206, 2008, DOI:10.3970/icces.2008.006.201

Abstract In the present work the significance of considering geometrical nonlinearity in the application of piezoelectric materials in order to improve the dynamic and stability characteristics of thin structures is shown. For the numerical investigations a finite shell element has been used which employs strain displacement relations based on the first-order shear deformation moderate rotation theory. An ANS formulation has been used to overcome membrane and shear locking. Two numerical examples are shown. The first example deals with increasing the critical buckling load by incorporating piezoelectric layers into the structure. In the second example the nonlinear vibrations of a cantilevered beam… More >

A. Takahashi¹, T. Shibata², K. Motoyama³, K. Misaji⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.1, pp. 1-15, 2017, DOI:10.3970/cmes.2017.113.001

Abstract A method for reducing the damage to a structure caused by an earthquake namely, using laminated rubber for seismic isolation is proposed, and the vibration characteristics of the rubber (which minimizes the seismic response of the structure during an earthquake) is optimized. A method called “Equivalent Linear System using Restoring Force Model of Power Function Type” (PFT-ELS) is applied to nonlinear vibration analysis of the rubber. In that analysis, a building with 15 layers of the laminated rubber is modeled. The seismic response of the building is analyzed, and the usefulness of the laminated rubber is demonstrated by comparing the… More >

Shueei-Muh Lin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.60, No.1, pp. 95-114, 2010, DOI:10.3970/cmes.2010.060.095

Abstract In this study, the mathematical model of double-beams assembly subjected to the a.c. electrostatic force is established. This is helpful for designing sensors and actuators. The boundary condition of this system is nonlinear and time-dependent. Obviously, this system is very complicated. A new solution method is here developed to derive the analytical solution. Because the a.c. electrostatic force includes the static and harmonic forces, the system is divided into the nonlinear static and dynamic subsystems. The exact static solution is presented. In the other hand, the boundary conditions of the dynamic subsystem are nonlinear and time-dependent. First, using the balanced… More >

Priyankar Datta¹, Manas C. Ray¹

CMC-Computers, Materials & Continua, Vol.49-50, No.1, pp. 47-80, 2015, DOI:10.3970/cmc.2015.049.047

Abstract This paper deals with the implementation of the one dimensional form of the fractional order derivative constitutive relation for three dimensional analysis of active constrained layer damping (ACLD) of geometrically nonlinear laminated composite plates. The constraining layer of the ACLD treatment is composed of the vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs). The von Kármán type nonlinear strain displacement relations are used to account for the geometric nonlinearity of the plates. A nonlinear smart finite element model (FEM) has been developed. Thin laminated substrate composite plates with various boundary conditions and stacking sequences are analyzed to verify the effectiveness of the… More >

Da-Guang Zhang^1,*, Hao-Miao Zhou¹

CMC-Computers, Materials & Continua, Vol.40, No.1, pp. 21-34, 2014, DOI:10.3970/cmc.2014.040.021

Abstract Nonlinear symmetric free vibration analyses are first presented for super elliptical isotropic thin plates with simply supported edge and clamped edge based on classical plate theory. Approximate solutions of super elliptical thin plates are obtained by Ritz method, and the validity can be confirmed by comparison with related researchers’ results. Numerical results confirm that the characteristics of nonlinear vibration behaviors are significantly influenced by different boundary conditions, vibration amplitudes, the power of the super ellipse, as well as ratio of major to minor axis. More >