scholarly journals DEVELOPMENT OF A DESIGN METHOD FOR DETERMINING THE ATTACHMENT OF THE EXHAUST MOUNTING MOUNTS

Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 141-147
Author(s):  
Rakhmatjon Rakhmatov ◽  
Vitaliy Krutolapov ◽  
Valeriy Zuzov
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Energy ◽  
Natural Frequencies ◽  
Design Method ◽  
Exhaust System ◽  
Element Model ◽  
Vehicle Body ◽  
Vibration Modes ◽  
The Finite Element Model

The article presents the developed method of determining the attachment points of the mounts of the exhaust system to the vehicle body. The requirements for the construction of a finite element model of the exhaust system are presented, the finite element model of the exhaust system is created, the results of natural frequencies and vibration modes and the strain energy of the structure are shown.

Identification of cracks in an Euler–Bernoulli beam using Bayesian inference and closed-form solution of vibration modes

2020 ◽  
pp. 146442072096971
Author(s):  
Tianyu Wang ◽  
Mohammad Noori ◽  
Wael A. Altabey
Keyword(s):  
Finite Element ◽  
Bayesian Inference ◽  
Finite Element Model ◽  
Crack Detection ◽  
Closed Form Solution ◽  
Element Model ◽  
Form Solution ◽  
Vibration Modes ◽  
Vibration Data ◽  
The Finite Element Model

Over the past two decades, extensive research has been carried out in the field of structural health monitoring for damage detection in structural systems. Some crack detection methods are based on the finite element model of a beam and use vibration data are developed. These methods identify the crack by updating of the finite element model according to the vibration data of structure. This paper proposes a novel method for crack detection in Euler–Bernoulli beams based on the closed-form solution of mode shapes using Bayesian inference. The expression of vibration modes is derived analytically with the crack parameters as unknown variables. Subsequently, the Bayesian inference is used to obtain the probability density function of crack parameters and to evaluate the uncertainty of the modes. Finally, the method is applied to a series of numerical examples, including a beam with a single-crack and multi-cracks, to verify the effectiveness of this method.

Hydroelastic Modal Analysis of the Perforated Cylindrical Shell in SMART

2011 ◽  
Author(s):  
Youngin Choi ◽  
Seungho Lim ◽  
Kyoung-Su Park ◽  
No-Cheol Park ◽  
Young-Pil Park ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Steam Generators ◽  
Structure Interaction ◽  
The Finite Element Model ◽  
Reactor Internals

The System-integrated Modular Advanced ReacTor (SMART) developed by KAERI includes components like a core, steam generators, coolant pumps, and a pressurizer inside the reactor vessel. Though the integrated structure improves the safety of the reactor, it can be excited by an earthquake and pump pulsations. It is important to identify dynamic characteristics of the reactor internals considering fluid-structure interaction caused by inner coolant for preventing damage from the excitations. Thus, the finite element model is constructed to identify dynamic characteristics and natural frequencies and mode shapes are extracted from this finite element model.

scholarly journals Analysis of dynamic characteristics of climbing formwork under wind loads

2019 ◽  
Vol 79 ◽  
pp. 01016
Author(s):  
Shicheng Hu ◽  
Jun Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Characteristics ◽  
Calculation Method ◽  
Design Method ◽  
Element Model ◽  
Wind Load ◽  
Bending Effect ◽  
Matlab Programming ◽  
The Finite Element Model

This article took the climbing formwork which constructed on the bridge at a height of 100 meters as the prototype, then established the finite element model and conducted modal analysis. The APDL language is used to load the wind load which is simulated by the Matlab programming then calculated the displacement and acceleration responses of the climbing formwork and further. The results show that the bending effect of the climbing formwork is more obvious. This calculation method of calculating the wind load, improve the anti-wind design method of the climbing formwork.

Displacement Properties of Newly Developed 3-Dimensional Piezoelectric Actuator at Various AC Frequencies

2007 ◽  
Vol 534-536 ◽  
pp. 1441-1444 ◽  
Author(s):  
Man Soon Yoon ◽  
Y.G. Choi ◽  
Soon Chul Ur
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Piezoelectric Actuator ◽  
Element Model ◽  
Vibration Modes ◽  
Maximum Strain ◽  
Electromechanical Properties ◽  
3 Dimensional ◽  
The Finite Element Model ◽  
Good Agreement

The electromechanical properties of a newly proposed 3-dimensional piezoelectric actuator have been investigated. Especially, the effects of 3-dimensional geometry on the maximum tip displacement were carefully investigated. As a result, it was found that the maximum strain of the 3-dimensional piezoelectric device was significantly enhanced up to 4.5 times higher than that of a disk shape device. This data was in good agreement with the finite element model analysis of strains and vibration modes. Moreover, the field -induced displacement stability of dome-shaped 3- dimensional piezoelectric actuator at various ac freguencies was superior to Rainbow actuator.

Advanced finite element cross-country ski boot model for mass optimization directions considering flexion stiffness

2017 ◽  
Vol 232 (3) ◽  
pp. 264-274
Author(s):  
Jurij Hladnik ◽  
Boris Jerman
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Energy ◽  
Element Model ◽  
High Mass ◽  
Model Accuracy ◽  
Cross Country Skiing ◽  
Cross Country ◽  
Front Region ◽  
The Finite Element Model

Flexion stiffness and mass were recognized as two important parameters of energy efficiency for modern top-class ski boots used in skate cross-country skiing. This article summarizes the study on mass optimization of the front foot region of an existing cross-country ski boot, while considering its flexion stiffness. For this purpose, a finite element model of the boot and an artificial foot for simulation of boot flexion stiffness measurement were made. The boot consists of textiles which require specific measurements for their characterization and special finite element material models for their realization. The finite element model was validated through a three-step validation process, in which flexion stiffness of the complete and stripped versions of the finite element model were compared with experimentally acquired flexion stiffness. Flexion stiffness contributions of individual boot components of the front foot region were acquired from the strain energy accumulated in their finite element. Using flexion stiffness and mass contributions and ratios between them (flexion stiffness to mass contributions), directions for flexion stiffness to mass contribution optimization of the boot’s front region were determined. The shoe-upper and shoe-cap were the most efficient regarding their flexion stiffness to mass contribution ratios and were suggested to be thickened. The soles had the highest potential for the boot’s flexion stiffness to mass contribution optimization due to their high mass contribution and relatively low flexion stiffness to mass contribution ratios. As a result, recommendations were made to reduce the soles’ size and/or increase their flexion stiffness to mass contribution ratios. These recommendations are similar to recommendations from a previous study, despite the higher finite element model accuracy and different method used to determine the flexion stiffness contributions.

scholarly journals Applied theory of bending vibration of the piezoelectric and piezomagnetic bimorph

2020 ◽  
Vol 10 (03) ◽  
pp. 2050007
Author(s):  
Do Thanh Binh ◽  
V. A. Chebanenko ◽  
Le Van Duong ◽  
E. Kirillova ◽  
Pham Manh Thang ◽  
...  
Keyword(s):  
Finite Element ◽  
Variational Principle ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Element Model ◽  
Applied Theory ◽  
Bending Vibration ◽  
Steady Vibrations ◽  
The Finite Element Model

Based on the variational principle, equations and boundary conditions for transverse steady vibrations of a bimorph consisting of a piezoelectric and piezomagnetic layers are obtained. The results of calculations of natural frequencies are compared with the finite element model of the device in ACELAN.

Nonlinear Energy Sink for Whole-Spacecraft Vibration Reduction

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Kai Yang ◽  
Ye-Wei Zhang ◽  
Hu Ding ◽  
Tian-Zhi Yang ◽  
Yang Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Vibration Reduction ◽  
Nonlinear Energy Sink ◽  
Element Model ◽  
Equivalent Model ◽  
Energy Sink ◽  
The Finite Element Model ◽  
Nonlinear Energy

A nonlinear energy sink (NES) approach is proposed for whole-spacecraft vibration reduction. Frequency sweeping tests are conducted on a scaled whole-spacecraft structure without or with a NES attached. The experimental transmissibility results demonstrate the significant reduction of the whole-spacecraft structure vibration over a broad spectrum of excitation frequency. The NES attachment hardly changes the natural frequencies of the structure. A finite element model is developed, and the model is verified by the experimental results. A two degrees-of-freedom (DOF) equivalent model of the scaled whole-spacecraft is proposed with the two same natural frequencies as those obtained via the finite element model. The experiment, the finite element model, and the equivalent model predict the same trends that the NES vibration reduction performance becomes better for the increasing NES mass, the increasing NES viscous damping, and the decreasing nonlinear stiffness. The energy absorption measure and the energy transition measure calculated based on the equivalent model reveals that an appropriately designed NES can efficiently absorb and dissipate broadband-frequency energy via nonlinear beats, irreversible targeted energy transfer (TET), or both for different parameters.

Factors Influencing Natural Frequencies in a Prestressed Concrete Panel for Damage Detection

2014 ◽  
Vol 69 (3) ◽  
Author(s):  
L. D. Goh ◽  
A. A. Rahman ◽  
N. Bakhary ◽  
B. H. Ahmad
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Detection ◽  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Element Model ◽  
Modal Parameters ◽  
Actual Structure ◽  
Modal Test ◽  
The Finite Element Model

Modal parameters such as natural frequencies, mode shapes, and damping ratios are widely used as damage indicators in the field of vibration-based damage detection. These modal parameters can be easily obtained by conducting the modal test on the actual structure or from the finite element model. However, many publications are focusing only on the relationship between the modal parameters and the changes in structural properties for damage detection. There are a limited number of publications discussing on the factors that may affect the modal parameters for damage detection. Hence, this paper provides a study on the level of influence of several factors on the natural frequencies of a prestressed concrete panel. The factors that are considered in this study are the size of element used in the numerical model, the dimension of the structural element, and the prestressing force applied in the prestressed concrete panel. The natural frequencies computed from the finite element model are also verified with the actual measured natural frequencies that are determined through the modal test conducted in the laboratory. 

scholarly journals Experimental Studies on Finite Element Model Updating for a Heated Beam-Like Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Kaipeng Sun ◽  
Yonghui Zhao ◽  
Haiyan Hu
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Model Updating ◽  
Element Model ◽  
Modal Parameters ◽  
Finite Element Model Updating ◽  
Time Varying ◽  
The Finite Element Model

An experimental study was made for the identification procedure of time-varying modal parameters and the finite element model updating technique of a beam-like thermal structure in both steady and unsteady high temperature environments. An improved time-varying autoregressive method was proposed first to extract the instantaneous natural frequencies of the structure in the unsteady high temperature environment. Based on the identified modal parameters, then, a finite element model for the structure was updated by using Kriging meta-model and optimization-based finite-element model updating method. The temperature-dependent parameters to be updated were expressed as low-order polynomials of temperature increase, and the finite element model updating problem was solved by updating several coefficients of the polynomials. The experimental results demonstrated the effectiveness of the time-varying modal parameter identification method and showed that the instantaneous natural frequencies of the updated model well tracked the trends of the measured values with high accuracy.

scholarly journals Experimental Study on Vibration of a Rotating Blade

1993 ◽  
Author(s):  
Y. C. Fan ◽  
M. S. Ju ◽  
Y. G. Tsuei
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Element Model ◽  
Element Analysis ◽  
Rotating Speed ◽  
Rotating Blade ◽  
Experimental Values ◽  
The Finite Element Model

The vibration of a rotating blade is investigated in this work. A rotor system is built and natural frequencies of the rotating blade are measured and compared with the numerical results from a finite element analysis. The experimental setup has a strain gage-based telemetry system and a piezoelectric shaker that rotates with the rotor. The finite element model of the beam is derived based on the Timoshenko beam theory. The effects of varying rotating speeds and stagger angles on the blade natural frequencies are studied. The results indicate that the natural frequencies calculated from the finite element model and the experimental values are in good agreement. It is found that the blade natural frequencies increase with the rotating speed in a nonlinear linear way. The effects of the stagger angle on the measured natural frequencies are not clear.

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