Experimental characterisation of sloshing tank dissipative behaviour in vertical harmonic excitation

2022 ◽  
Vol 109 ◽  
pp. 103478
Author(s):  
Francesco Saltari ◽  
Marco Pizzoli ◽  
Giuliano Coppotelli ◽  
Francesco Gambioli ◽  
Jonathan E. Cooper ◽  
...  
Keyword(s):  
Harmonic Excitation ◽  
Experimental Characterisation

Localization of a harmonic excitation load in a bi-clamped beam using finite element method and artificial neural network

2019 ◽  
Author(s):  
Otavio Duarte Zotelli Boaventura ◽  
Daniel Henrique de Sousa Obata ◽  
Matheus Proença ◽  
Amarildo Tabone Paschoalini
Keyword(s):  
Neural Network ◽  
Finite Element Method ◽  
Artificial Neural Network ◽  
Finite Element ◽  
Harmonic Excitation ◽  
Artificial Neural ◽  
Element Method

scholarly journals Experimental characterisation of a diesel engine running on polypropylene oils produced at different pyrolysis temperatures

Fuel ◽  
2018 ◽  
Vol 211 ◽  
pp. 797-803 ◽  
Author(s):  
Ioannis Kalargaris ◽  
Guohong Tian ◽  
Sai Gu
Keyword(s):  
Diesel Engine ◽  
Experimental Characterisation

scholarly journals Nonlinear vibration of knitted spacer fabric under harmonic excitation

2020 ◽  
Vol 15 ◽  
pp. 155892502098356
Author(s):  
Fuxing Chen ◽  
Hong Hu
Keyword(s):  
Nonlinear Vibration ◽  
Harmonic Balance Method ◽  
Harmonic Excitation ◽  
Polyurethane Foams ◽  
Excitation Level ◽  
Harmonic Amplitude ◽  
Damping Force ◽  
Spacer Fabric ◽  
Fabric System ◽  
Quadratic Stiffness

Knitted spacer fabrics can be an alternative material to typical rubber sponges and polyurethane foams for the protection of the human body from vibration exposure, such as automotive seat cushions and anti-vibration gloves. To provide a theoretical basis for the understanding of the nonlinear vibration behavior of the mass-spacer fabric system under harmonic excitation, experimental, analytical and numerical methods are used. Different from a linear mass-spring-damper vibration model, this study builds a phenomenological model with the asymmetric elastic force and the fractional derivative damping force to describe the periodic solution of the mass-spacer fabric system under harmonic excitation. Mathematical expression of the harmonic amplitude versus frequency response curve (FRC) is obtained using the harmonic balance method (HBM) to solve the equation of motion of the system. Parameter values in the model are estimated by performing curve fit between the modeled FRC and the experimental data of acceleration transmissibility. Theoretical analysis concerning the influence of varying excitation level on the FRCs is carried out, showing that nonlinear softening resonance turns into nonlinear hardening resonance with the increase of excitation level, due to the quadratic stiffness term and the cubic stiffness term in the model, respectively. The quadratic stiffness term also results in biased vibration response and causes an even order harmonic distortion. Besides, the increase of excitation level also results in elevated peak transmissibility at resonance.

Experimental characterisation of irradiance and spectral non-uniformity and its impact on multi-junction solar cells: Refractive vs. reflective optics

2021 ◽  
Vol 225 ◽  
pp. 111061
Author(s):  
Jose M. Saura ◽  
Pedro M. Rodrigo ◽  
Florencia M. Almonacid ◽  
Daniel Chemisana ◽  
Eduardo F. Fernández
Keyword(s):  
Solar Cells ◽  
Reflective Optics ◽  
Experimental Characterisation

scholarly journals Vibration Equation of Fractional Order Describing Viscoelasticity and Viscous Inertia

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 850-856 ◽  
Author(s):  
Jun-Sheng Duan ◽  
Yun-Yun Xu
Keyword(s):  
Fractional Derivative ◽  
Fractional Order ◽  
Fractional Derivatives ◽  
Harmonic Excitation ◽  
Steady State Response ◽  
Vibration System ◽  
Derivative Operator ◽  
Vibration Equation ◽  
State Response ◽  
Frequency Relation

Abstract The steady state response of a fractional order vibration system subject to harmonic excitation was studied by using the fractional derivative operator ${}_{-\infty} D_t^\beta,$where the order β is a real number satisfying 0 ≤ β ≤ 2. We derived that the fractional derivative contributes to the viscoelasticity if 0 < β < 1, while it contributes to the viscous inertia if 1 < β < 2. Thus the fractional derivative can represent the “spring-pot” element and also the “inerterpot” element proposed in the present article. The viscosity contribution coefficient, elasticity contribution coefficient, inertia contribution coefficient, amplitude-frequency relation, phase-frequency relation, and influence of the order are discussed in detail. The results show that fractional derivatives are applicable for characterizing the viscoelasticity and viscous inertia of materials.

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