scholarly journals NMSBA High Frequency Modal Analysis of a Solid Metal Cylinder

2014 ◽  
Author(s):  
Jill Blecke ◽  
Hartono Sumali
Keyword(s):  
Modal Analysis ◽  
High Frequency ◽  
Solid Metal ◽  
Metal Cylinder

scholarly journals EXPERIMENTAL MODAL ANALYSIS OF A FLOOR OF A WOODEN HOUSE An Analysis of the floor vibration which is predominanted with high frequency by running train

2009 ◽  
Vol 15 (29) ◽  
pp. 151-154
Author(s):  
Yasuyuki SANO ◽  
Yasuhiko IZUMI ◽  
Shigenori YOKOSHIMA ◽  
Ryuta TOMITA ◽  
Toshihisa ISHIBASHI ◽  
...  
Keyword(s):  
Modal Analysis ◽  
High Frequency ◽  
Experimental Modal Analysis ◽  
Wooden House ◽  
Floor Vibration

Mass-Transfer from Solid Metal Cylinder into Liquid Metal

1966 ◽  
Vol 52 (12) ◽  
pp. 1748-1762 ◽  
Author(s):  
Mineo KOSAKA ◽  
Susumu MINOWA
Keyword(s):  
Mass Transfer ◽  
Liquid Metal ◽  
Solid Metal ◽  
Metal Cylinder

High Frequency Analysis of a Dynamically Coupled Parallel Plate System

2017 ◽  
Author(s):  
Dean R. Culver ◽  
Earl Dowell
Keyword(s):  
Modal Analysis ◽  
Frequency Analysis ◽  
High Frequency ◽  
Parallel Plate ◽  
Damping Ratio ◽  
Parallel Plates ◽  
Linear Spring ◽  
Stiffness And Damping ◽  
Plate System

The behavior of a system comprised of two parallel plates coupled by a discrete, linear spring and damper is studied. Classical Modal Analysis (CMA) is used to illustrate this behavior, while specifically observing the effects of varying the stiffness and damping ratio of the coupling elements. Conditions under which the coupling may be approximated as rigid are identified. Additionally, conditions under which the coupling displacement reaches its maximum and minimum values are identified. This work also lays the groundwork for extending Asymptotic Modal Analysis (AMA) to systems with discrete, elastic, and dissipative coupling.

Development of a Modal Selection Method for Full Strain Field Estimation

2020 ◽  
Author(s):  
Gen Fu ◽  
Alexandrina Untaroiu
Keyword(s):  
Modal Analysis ◽  
Frequency Band ◽  
High Frequency ◽  
Selection Method ◽  
Operational Modal Analysis ◽  
High Frequency Band ◽  
Full Field ◽  
Modal Selection ◽  
Data Expansion ◽  
The Impact

Abstract Full field response of a structure is critical for evaluating the performance of large slender structures. Since only several discrete measurements can be acquired during operation, the data expansion method is important for the estimation of the full field responses of the large complex structure. In previous studies, modal transformation methods were mainly applied in model reduction/expansion and global shape sensing. Compared to other expansion methods, the modal method is straightforward to implement and computational efficient, which makes it the most suitable approach for real-time expansion. However, only the first several modes were included in the modal transformation method in previous studies. Since the errors due to truncated mode components can occur under high frequency band excitations, it is necessary to include all of the modes that contribute significantly to the responses of the structure. Therefore, in this study, a modal selection method based on operational modal analysis (OMA) is proposed for selecting proper modes. The modal characteristics of the system were derived with the strain data at several discrete locations. The contribution of each mode was quantified. By sorting the modes based on their contribution, the most significant modes can be used in the expansion process. Two operational modal analysis methods, stochastic system identification (SSI) and frequency domain decomposition (FDD), were considered and compared. The proposed approach was implemented with a computational model. Considerable improvement has been observed when high bandwidth excitations were added. The proposed modal selection method can successfully rank the participated modes. It can improve the accuracy of the modal transformation approach as shown in the impact loading case. It can be used for data expansion even when high frequency band is excited. Finally, we believe the novel methods presented in this study could be used in the development of more reliable health monitoring systems for turbomachinery.

3D Modal Analysis of a Loaded Tire with Binary Random Noise Excitation

2019 ◽  
Vol 48 (3) ◽  
pp. 207-223
Author(s):  
Ipar Ferhat ◽  
Rodrigo Sarlo ◽  
Pablo A. Tarazaga
Keyword(s):  
Modal Analysis ◽  
High Frequency ◽  
Random Noise ◽  
Real Life ◽  
Laser Doppler Vibrometer ◽  
Static Condition ◽  
Three Dimensions ◽  
Vibration Measurement ◽  
Mode Shapes ◽  
Testing Techniques

ABSTRACT Modal analysis of tires has been a fundamental part of tire research aimed at capturing the dynamic behavior of a tire. An accurate expression of tire dynamics leads to an improved tire model and a more accurate prediction of tire behavior in real-life operations. Therefore, the main goal of this work is to improve the tire-testing techniques and data range to obtain the best experimental data possible using the current technology. With this goal in mind, we propose novel testing techniques such as piezoelectric excitation, high-frequency bandwidth data, and noncontact vibration measurement. High-frequency data enable us to capture the coupling between the wheel and tire as well as the coupling between airborne and structure-borne noise. Piezoelectric excitation eliminates the dynamic coupling of shakers and the inconsistency of force magnitude and direction of impact hammers as well as added mass effect. Noncontact vibration measurements using three-dimensional (3D) scanning laser Doppler vibrometer (SLDV) are superior to accelerometers because of no mass loading, a high number of measurement points in three dimensions, and high sensitivity. In this work, a modal analysis is carried out for a loaded tire in a static condition. Because of the highly damped nature of tires, multiple input excitation with binary random noise signal is used to increase the signal strength. Mode shapes of the tire are obtained and compared using both accelerometers and SLDV measurements.

The Transient Response of Structures Using Asymptotic Modal Analysis

1998 ◽  
Vol 65 (1) ◽  
pp. 258-265 ◽  
Author(s):  
R. R. Reynolds ◽  
E. H. Dowell
Keyword(s):  
Numerical Methods ◽  
Finite Elements ◽  
Modal Analysis ◽  
Impulse Response ◽  
Transient Response ◽  
High Frequency ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Frequency Range ◽  
Modal Solution

The transient response of a structure is predicted using an asymptotic modal approximation of the classical modal solution. The method is aimed at estimating the impulse response problem for high frequency regimes where typical numerical methods (e.g., finite elements) are impractical. As an example, the response of a thin elastic panel is modeled in a frequency range that includes a sufficient number of modes. Both impulsive and arbitrary forms of excitation are considered. It is shown that the asymptotic modal analysis yields an excellent estimate of both the local displacement near the excitation location and of the spatially averaged transient response of the panel for moderate time spans after the excitation is applied. Furthermore, as this approach does not require that the mode shapes or natural frequencies of the structure to be calculated, it is an extremely efficient technique.

scholarly journals High Frequency Analysis of a Point-Coupled Parallel Plate System

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Dean R. Culver ◽  
Earl H. Dowell
Keyword(s):  
Modal Analysis ◽  
High Frequency ◽  
Parallel Plate ◽  
Energy Analysis ◽  
Spatial Relationship ◽  
Statistical Energy Analysis ◽  
Mean Square ◽  
Parallel Plates ◽  
Modal Density ◽  
Plate System

The root-mean-square (RMS) response of various points in a system comprised of two parallel plates coupled at a point undergoing high frequency, broadband transverse point excitation of one component is considered. Through this prototypical example, asymptotic modal analysis (AMA) is extended to two coupled continuous dynamical systems. It is shown that different points on the plates respond with different RMS magnitudes depending on their spatial relationship to the excitation or coupling points in the system. The ability of AMA to accurately compute the RMS response of these points (namely, the excitation point, the coupling points, and the hot lines through the excitation or coupling points) in the system is shown. The behavior of three representative prototypical configurations of the parallel plate system considered is: two similar plates (in both geometry and modal density), two plates with similar modal density but different geometry, and two plates with similar geometry but different modal density. After examining the error between reduced modal methods (such as AMA) to classical modal analysis (CMA), it is determined that these several methods are valid for each of these scenarios. The data from the various methods will also be useful in evaluating the accuracy of other methods including statistical energy analysis (SEA).

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