scholarly journals Identification of Engine Inertia Parameters and System Dynamic Stiffness via In Situ Method

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Chuanyan Xu ◽  
Xun Gong ◽  
Lixue Meng ◽  
Aijuan Li
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Dynamic Stiffness ◽  
System Dynamic ◽  
Response Functions ◽  
In Situ Method ◽  
Element Simulation ◽  
Good Consistency ◽  
Inertia Parameters

An in situ method is presented to identify ten engine inertia parameters and system dynamic stiffness from the frequency response functions. The ten engine inertia parameters and system dynamic stiffness are estimated from two distinct steps. The accuracy of the proposed technique is verified by finite element simulation, and then the generality is validated using an engine supported by a specially designed curved bar spring. The locations of the measure points on the results are also carefully investigated. The identification of system dynamic stiffness is validated comparing with the engine with an auxiliary plate, which shows good consistency with the results identified from the study.

scholarly journals Young’s Modulus of Polycrystalline Titania Microspheres Determined by In Situ Nanoindentation and Finite Element Modeling

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Peida Hao ◽  
Yanping Liu ◽  
Yuanming Du ◽  
Yuefei Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Deformation Mechanisms ◽  
Displacement Curve ◽  
Element Simulation ◽  
Nanoindentation Experiment ◽  
Force Displacement

In situ nanoindentation was employed to probe the mechanical properties of individual polycrystalline titania (TiO2) microspheres. The force-displacement curves captured by a hybrid scanning electron microscope/scanning probe microscope (SEM/SPM) system were analyzed based on Hertz’s theory of contact mechanics. However, the deformation mechanisms of the nano/microspheres in the nanoindentation tests are not very clear. Finite element simulation was employed to investigate the deformation of spheres at the nanoscale under the pressure of an AFM tip. Then a revised method for the calculation of Young’s modulus of the microspheres was presented based on the deformation mechanisms of the spheres and Hertz’s theory. Meanwhile, a new force-displacement curve was reproduced by finite element simulation with the new calculation, and it was compared with the curve obtained by the nanoindentation experiment. The results of the comparison show that utilization of this revised model produces more accurate results. The calculated results showed that Young’s modulus of a polycrystalline TiO2microsphere was approximately 30% larger than that of the bulk counterpart.

Finite Element Simulation of Frequency Response of MEMS-Microphone

2018 ◽  
Vol 47 (3) ◽  
pp. 211-216 ◽  
Author(s):  
D. M. Grigor’ev ◽  
I. V. Godovitsyn ◽  
V. V. Amelichev ◽  
S. S. Generalov
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Finite Element Simulation ◽  
Element Simulation ◽  
Mems Microphone

Change of modal parameters due to crack growth in a tripod tower platform

1993 ◽  
Vol 20 (5) ◽  
pp. 801-813 ◽  
Author(s):  
Yin Chen ◽  
A. S. J. Swamidas
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Experimental Results ◽  
Modal Testing ◽  
Modal Parameters ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Strain Frequency

Strain gauges, along with an accelerometer and a linear variable displacement transducer, were used in the modal testing to detect a crack in a tripod tower platform structure model. The experimental results showed that the frequency response function of the strain gauge located near the crack had the most sensitivity to cracking. It was observed that the amplitude of the strain frequency response function at resonant points had large changes (around 60% when the crack became a through-thickness crack) when the crack grew in size. By monitoring the change of modal parameters, especially the amplitude of the strain frequency response function near the critical area, it would be very easy to detect the damage that occurs in offshore structures. A numerical computation of the frequency response functions using finite element method was also performed and compared with the experimental results. A good consistency between these two sets of results has been found. All the calculations required for the experimental modal parameters and the finite element analysis were carried out using the computer program SDRC-IDEAS. Key words: modal testing, cracking, strain–displacement–acceleration frequency response functions, frequency–damping–amplitude changes.

Mesh Technique for the Finite Element Simulation of Acoustic Fluid-Solid Coupled Analysis

2014 ◽  
Vol 555 ◽  
pp. 452-457
Author(s):  
Marian Bogdan Neagoe ◽  
Sorin Cănănău ◽  
Lucian Mândrea
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Noise Level ◽  
Vibration Analysis ◽  
Fluid Model ◽  
Coupled Analysis ◽  
Vehicle Engineering ◽  
Element Simulation ◽  
Acoustic Fluid ◽  
Mesh Technique

Noise and vibration analysis has become thoroughly researched in vehicle engineering where is needed to keep the noise level low and affect the vehicle users. The analysis in the paper shows a frequency response study where we will determine the frequency response on a coupled structure-fluid model. The study will be made on a simplified “train wagon“ model to show in a better way the differences between a perfect coupled structure-fluid model and a non-conformal coupling. The analysis shows that the distribution of the nodes for the two cases influences the results.

scholarly journals Nonlinear oscillations of a sandwich plate with a 3D-printed honeycomb core

2021 ◽  
Vol 2021 (4) ◽  
pp. 104-117
Author(s):  
K.V. Avramov ◽  
◽  
B.V. Uspensky ◽  
I.I. Derevianko ◽  
◽  
...  
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Finite Element Simulation ◽  
Sandwich Plate ◽  
Nonlinear Oscillations ◽  
Ritz Method ◽  
Forced Oscillations ◽  
Homogeneous Layer ◽  
Honeycomb Core ◽  
Element Simulation

A three-layer sandwich plate with a FDM-printed honeycomb core made of polycarbonate is considered. The upper and lower faces of the sandwich are made of a carbon fiber-reinforced composite. To study the response of the sandwich plate, the honeycomb core is replaced with a homogeneous layer with appropriate mechanical properties. To verify the honeycomb core model, a finite-element simulation of the representative volume of the core was performed using the ANSYS software package. A modification of the high-order shear theory is used to describe the structure dynamics. The assumed-mode method is used to simulate nonlinear forced oscillations of the plate. The Rayleigh–Ritz method is used to calculate the eigenfrequencies and eigenmodes of the plate, in which the displacement of the plate points during nonlinear oscillations are expanded. This technique allows one to obtain a finite-degree-of-freedom nonlinear dynamic system, which describes the oscillations of the plate. The frequency response of the system is calculated using the continuation approach applied to a two-point boundary value problem for nonlinear ordinary differential equations and the Floquet multiplier method, which allows one to determine the stability and bifurcations of periodic solutions. The resonance behavior of the system is analyzed using its frequency response. The proposed technique is used to analyze the forced oscillations of a square three-layer plate clamped along the contour. The results of the analysis of the free oscillations of the plate are compared with those of ANSYS finite-element simulation, and the convergence of the results with increasing number of basis functions is analyzed. The comparison shows that the results are in close agreement. The analysis of the forced oscillations shows that the plate executes essentially nonlinear oscillations with two saddle-node bifurcations in the frequency response curve, in which the periodic motion stability of the system changes. The nonlinear oscillations of the plate near the first fundamental resonance are mostly monoharmonic. They may be calculated using the describing function method.

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