Finite-element analysis of second-harmonic generation in AlGaAs waveguides

2000 ◽  
Vol 36 (3) ◽  
pp. 282-289 ◽  
Author(s):  
F.A. Katsriku ◽  
B.M.A. Rahman ◽  
K.T.V. Grattan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Element Analysis

Time-Domain Spectral Finite Element Method for Modeling Second Harmonic Generation of Guided Waves Induced by Material, Geometric and Contact Nonlinearities in Beams

2020 ◽  
Vol 20 (10) ◽  
pp. 2042005
Author(s):  
Shuai He ◽  
Ching-Tai Ng ◽  
Carman Yeung
Keyword(s):  
Finite Element ◽  
Second Harmonic Generation ◽  
Damage Detection ◽  
Harmonic Generation ◽  
Time Domain ◽  
Second Harmonic ◽  
Breathing Crack ◽  
Geometric Nonlinearities ◽  
Contact Nonlinearity ◽  
Spectral Finite Element

This study proposes a time-domain spectral finite element (SFE) method for simulating the second harmonic generation (SHG) of nonlinear guided wave due to material, geometric and contact nonlinearities in beams. The time-domain SFE method is developed based on the Mindlin–Hermann rod and Timoshenko beam theory. The material and geometric nonlinearities are modeled by adapting the constitutive relation between stress and strain using a second-order approximation. The contact nonlinearity induced by breathing crack is simulated by bilinear crack mechanism. The material and geometric nonlinearities of the SFE model are validated analytically and the contact nonlinearity is verified numerically using three-dimensional (3D) finite element (FE) simulation. There is good agreement between the analytical, numerical and SFE results, demonstrating the accuracy of the proposed method. Numerical case studies are conducted to investigate the influence of number of cycles and amplitude of the excitation signal on the SHG and its performance in damage detection. The results show that the amplitude of the SHG increases with the numbers of cycles and amplitude of the excitation signal. The amplitudes of the SHG due to material and geometric nonlinearities are also compared with the contact nonlinearity when a breathing crack exists in the beam. It shows that the material and geometric nonlinearities have much less contribution to the SHG than the contact nonlinearity. In addition, the SHG can accurately determine the crack location without using the reference data. Overall, the findings of this study help further advance the use of SHG for damage detection.

scholarly journals Finite Element Analysis of Energy-Trapped Second Harmonic Thickness Extensional Vibration

1988 ◽  
Vol 27 (S1) ◽  
pp. 105
Author(s):  
Tsutomu Okada ◽  
Toshihiko Kittaka ◽  
Akira Ando ◽  
Yukio Sakabe
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Second Harmonic ◽  
Element Analysis

scholarly journals Galerkin Finite-Element Method for the Analysis of the Second Harmonic Generation in Wagon Wheel Fibers

2017 ◽  
Vol 11 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Motaharesadat Hosseinian ◽  
Ali Reza Ahmadi ◽  
Maryam Alvanforoush ◽  
Ali Asghar Zakerifar ◽  
Mohammad Bolorizadeh ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Galerkin Finite Element Method ◽  
Galerkin Finite Element ◽  
Wagon Wheel ◽  
Element Method

Continuation Finite Element Simulation of Second Harmonic Generation in Photonic Crystals

2011 ◽  
Vol 10 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Gang Bao ◽  
Zhengfu Xu ◽  
Jianhua Yuan
Keyword(s):  
Finite Element ◽  
Photonic Crystals ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Conversion Efficiency ◽  
Computational Study ◽  
Second Harmonic ◽  
Continuation Method ◽  
One Dimensional ◽  
Photonic Band

AbstractA computational study on the enhancement of the second harmonic generation (SHG) in one-dimensional (1D) photonic crystals is presented. The mathematical model is derived from a nonlinear system of Maxwell’s equations, which partly overcomes the shortcoming of some existing models based on the undepleted pump approximation. We designed an iterative scheme coupled with the finite element method which can be applied to simulate the SHG in one dimensional nonlinear photonic band gap structures in our previous work. For the case that the nonlinearity is strong which is desirable to enhance the conversion efficiency, a continuation method is introduced to ensure the convergence of the iterative procedure. The convergence of our method is fast. Numerical experiments also indicate the conversion efficiency of SHG can be significantly enhanced when the frequencies of the fundamental and the second harmonic wave are tuned at the photonic band edges. The maximum total conversion efficiency available reaches more than 50% in all the cases studied.

scholarly journals Bolted joint integrity monitoring with second harmonic generated by guided waves

2018 ◽  
Vol 18 (1) ◽  
pp. 193-204 ◽  
Author(s):  
Yi Yang ◽  
Ching-Tai Ng ◽  
Andrei Kotousov
Keyword(s):  
Finite Element ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Guided Waves ◽  
Second Harmonic ◽  
Fatigue Cracks ◽  
Bolted Joint ◽  
Contact Nonlinearity ◽  
Bolt Loosening ◽  
Joint Integrity

In this study, the second harmonic generation due to the contact nonlinearity caused by bolt loosening is studied experimentally and numerically using three-dimensional explicit finite element simulations. In particular, it is demonstrated that the magnitude of the second harmonic generation normally increases with the loosening of the bolted joint, and there is a reasonable agreement between the numerical simulations and experimental results. The finite element model, which was validated against the experimentally measured data, is further utilized to investigate an important practical situation when a loosened bolt is weakened by fatigue cracks located at the edge of the hole. The numerical case studies show that the contact nonlinearity and the change of the behaviour of the second harmonic generation with the tightening level are very different to the corresponding results with the fatigue cracks. This identified difference in the second harmonic generation behaviour can serve as an indicator of the bolted joint integrity and thus provide early warning for engineers to make decision on the necessity of carrying out further safety inspections. Overall, the findings of this study provide improved physical insights into second harmonic generation for bolt loosening, which can be used to further advance damage detection techniques using nonlinear guided waves.

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