scholarly journals Assessment of Antenna Mounting Building Structural Strength using Microtremor Analysis

2021 ◽  
Vol 1197 (1) ◽  
pp. 012057
Author(s):  
Venkata Lakshmi Gullapalli ◽  
R RaghuNandanKumar ◽  
G R Reddy
Keyword(s):  
Natural Frequency ◽  
Structural Strength ◽  
Resonance Effect ◽  
Static Loads ◽  
Antenna Structure ◽  
Existing Building ◽  
Ground Station ◽  
Natural Modes ◽  
Recorded Data ◽  
Fft Analysis

Abstract Any satellite tracking ground station requires fully steerable dish shaped antenna for fixed satellite services. Antenna foundations require special consideration, because they transmit dynamic loads to soil and foundation system, in addition to static loads due to self-weight of foundation, antenna and its accessories. Antenna foundations are of ground foundation or roof top i.e on buildings based on Radio Frequency requirements. To install antennas on existing building, the building should have required strength. To assess the building strength, building natural frequency and damping ratios are determined using Microtremor recorded data. For rotating Antennas, the required building frequency should be more than 8 Hz to avoid resonance effect of antenna structure natural frequency with servo frequency. In this study, the data is collected for building located at National Remote Sensing Centre, ISRO, Shadnagar, Hyderabad by mounting sensor at 3 locations of building. The data collected is analyzed using View 2002 software. FFT analysis is carried out to identify predominant natural modes and frequencies of the Building.

STUDY OF THE DYNAMIC CHARACTERISTICS OF PIEZOELECTRIC MICROCANTILEVER PROBE

2013 ◽  
Vol 27 (23) ◽  
pp. 1350165 ◽  
Author(s):  
AN-PING LIU ◽  
XIAO-NAN SUN ◽  
XING-XING YAO
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Resonance Effect ◽  
Dynamic Mode ◽  
Force Frequency ◽  
Induced Voltage ◽  
Position Change ◽  
Peak Voltage ◽  
Static Mode ◽  
Piezoelectric Microcantilever

A piezoelectric microcantilever probe is designed for the scanning probe microscope working in tapping mode, and the dynamic characteristics of the piezoelectric microcantilever probe are tested by experiments. The results indicate that due to the resonance effect, induced voltage and sensitivity of microcantilever are not only associated with force magnitude, but also with the force frequency. When the frequency is close to the first natural frequency 97.04 Hz, the output voltage rapidly increases and reaches a maximum value 62.0 mV. The peak voltage value and its position change as the structure size changes. In dynamic mode, the peak voltage is an order of magnitude higher than that in the static mode, and the dynamic mode is more sensitive. Selecting a reasonable size for the device can help to improve the first-order natural frequency and improve the response speed of piezoelectric microcantilever probe during nanomicro detecting.

Theoretical Determination of Natural Modes of Deck Vibrations

1966 ◽  
Vol 3 (01) ◽  
pp. 66-79
Author(s):  
Robert D. Short
Keyword(s):  
Boundary Conditions ◽  
Natural Frequency ◽  
Maximum Error ◽  
Nodal Line ◽  
The Other ◽  
Mode Shapes ◽  
Theoretical Determination ◽  
Natural Modes

Six methods for calculating the natural frequency and mode shapes of cross-stiffened plating were examined particularly for their application to plating with a large number of small closely spaced stiffeners in one direction supported by a few deep girders in the other. The best method was able to predict at least 1 6 frequencies (all that were measured) of a model with a maximum error of less than 15 percent when proper boundary conditions were used. The maximum error in nodal-line locations for the best method was 5.2 percent of the span

scholarly journals COMPLEX MODEL OF MARKET PRICE DEVELOPMENT AND ITS SIMULATION

2015 ◽  
Vol 16 (4) ◽  
pp. 786-807 ◽  
Author(s):  
Bohumil Stádník ◽  
Algita Miečinskienė
Keyword(s):  
Resonance Effect ◽  
Market Price ◽  
Complex Model ◽  
Simulation Environment ◽  
Asset Valuation ◽  
Price Development ◽  
The Real ◽  
Real Price ◽  
Price Distribution ◽  
Fft Analysis

The purpose of this study is to suggest a complex model of market price development for liquid assets, which is able to simulate all of the main features particular to the real price development and has a realistic financial explanation. First, the paper defines assumptions for the model construction from empirically observed processes. Then, the model is implemented in the real simulation environment. Finally, the ability of the model is checked to simulate empirically observed features, e.g. leptokurtic characteristics or skewness of the price distribution. Also, this paper newly defines and implements the resonance effect. FFT analysis is used to support oscillation processes. Finally, selected markets are provided with parameter optimisation of the model based on empirical observations. It was found that the model built under the previously mentioned assumptions was able to explain empirically observed effects that reversely support the correctness of those assumptions. The practical value of the constructed model can be found in many areas, including risk management and asset valuation.

Damping Measurement of Bending Vibration in Alpine Skis: An Improvement of Standard ISO 6267

2006 ◽  
Vol 5-6 ◽  
pp. 199-206 ◽  
Author(s):  
Giulio Fanti ◽  
R. Basso ◽  
V. Montauti
Keyword(s):  
Natural Frequency ◽  
Experimental Test ◽  
Vibration Mode ◽  
Damping Ratio ◽  
Time History ◽  
Measuring Method ◽  
Bending Vibration ◽  
Natural Modes ◽  
The Fourier Transform

The ISO 6267 standard defines a damping measuring method in terms of the half-time of the vibration of clamped alpine skis that is mainly related to the first vibration mode only. By means of the experimental test done in laboratory, it is shown that this method is not able to completely characterize the damping of the skis that depends on the vibration mode considered. For example in the case a ski sample, damping ratio varies from 0.45%±0.05% of the first mode to 2.1%±0.1% of the fourth one. The experimental test done on ski tracks by means of piezo-accelerometers placed on the skis running at speed of 12.5 m/s showed that the skis vibrate according to a combination of at least the first 4 vibration modes and that the snow better excites frequencies greater than the first one. As the excitation frequencies on the skis during the descent are much higher than the first natural frequency of the ski, it appears not correct to hypothesize that only the damping coefficient relative to the first natural frequency is representative of the ski vibrations. To improve the UNI ISO 6267 standard, a new method based on the Fourier Transform filtering to separate the time history into the vibration components is proposed for the characterization of the ski damping that is variable with its natural modes.

scholarly journals PERKUATAN (STRENGTHENING) STRUKTUR KOLOM DENGAN METODA PENAMBAHAN TULANGAN

2012 ◽  
Vol 16 (3) ◽  
pp. 135
Author(s):  
Ignatius Christiawan
Keyword(s):  
Performance Evaluation ◽  
Structural Strength ◽  
Concrete Columns ◽  
Structure Calculation ◽  
Practical Calculation ◽  
Existing Building ◽  
Building Collapse ◽  
Analysis And Design ◽  
Building Plans ◽  
Increasing Load

Ignatius Chistiawan, in this paper explain that in the management of buildings, frequent damage to buildings due to the increasing load beyond the load plan. Safety of building users to the dangers of building collapse is the main priority. The addition of load beyond the load on the building plans because of changes in building functions often lead to the collapse of the building. The addition of load beyond the load on the building plans because of changes in building functions often lead to the collapse of buildings. Structural strength evaluation to the condition of existing building is required and when it is necessary to give reinforcement to the plate, beams and columns before adding a new load. additional reinforcement is one way of strengthening the column. Research was focused on performance evaluation of structure on existing condition relate at regulation of the Procedure of Concrete Structure Calculation for the SNI 2847-2002. From some previous research, the basics of analysis and design of flexible and practical calculation examples retrofitting columns with the addition of reinforcement can be concluded that this method is easy and practically implemented and can improve the flexural strength of reinforced concrete columns. Keywords : load addition, evaluation, strength, safety.

Dynamic Characteristics of Vibrating Screen with Determinate Structure and Statically Indeterminate Structure

2010 ◽  
Vol 34-35 ◽  
pp. 1850-1854 ◽  
Author(s):  
Jun Xia Yan ◽  
Chu Sheng Liu ◽  
La La Zhao
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Design Process ◽  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Vibration Mode ◽  
Structural Strength ◽  
Finite Element Technology ◽  
Natural Vibration Mode ◽  
Twisting Deformation

Analyzed vibrating screen’s dynamic characteristics of determinate structure and statically indeterminate structure, calculate natural frequency, natural vibration mode and dynamic response based on finite element technology. The results show that the vibrating screen’s structural strength is increased and the natural frequency of bending and twisting deformation is improved by means of the adoption of statically indeterminate structure. The natural frequency is far from work frequency which means the structure can avoid resonance effectively. Statically indeterminate structure provides a big structure intensity and stiffness to meet vibrating screen’s needs in the design process.

The Resonance Effect of External Vertical Vibration on a Single Nuclear-Coupled Boiling Channel System With Forced Flows

2017 ◽  
Author(s):  
Yuh-Ger Lin ◽  
Jin-Der Lee ◽  
Shao-Wen Chen ◽  
Jinn-Jer Peir
Keyword(s):  
Phase Change ◽  
Natural Frequency ◽  
Vibration Frequency ◽  
Natural Frequencies ◽  
Channel Model ◽  
Resonance Effect ◽  
Stable Region ◽  
Stable States ◽  
Initial State ◽  
Channel System

The present study adopts the single nuclear-coupled boiling channel model integrated with oscillating vertical seismic accelerations to investigate the seismic-induced effect on a single nuclear-coupled boiling channel system. The nonlinear dynamics and stabilities of a single nuclear-coupled boiling channel are investigated through nonlinear analyses. The void-reactivity feedback would destabilize the system as that reported in the literatures. The natural frequencies of the stable states are widely explored. The results indicate that the natural frequency of initial state could depend on the parameters of phase change number and subcooling number. It tends to increase as the increase in the phase change number (operating power) or the decrease in the subcooling number (inlet subcooling). Notably, the system natural frequencies distributed in the stable region are located within the common range of seismic vibration frequency. For the concern of reactor safety, the present study investigates the seismic-induced resonance effect on a nuclear-coupled boiling channel system. The results illustrate that the resonance oscillations could be triggered if the external vibration frequency is the same as the system natural frequency. Moreover, the strength of resonance effect may depend on the inherent stability characteristics of the initial states.

Free Torsional Vibration Characteristics of a Closed-Form Planetary Gear Set

2013 ◽  
Vol 300-301 ◽  
pp. 1042-1047 ◽  
Author(s):  
Qi Lin Huang ◽  
Yong Wang ◽  
Zhi Pu Huo ◽  
Jun Gang Wang ◽  
Ruo Yu Sheng
Keyword(s):  
Free Vibration ◽  
Closed Form ◽  
Dynamic Model ◽  
Natural Frequency ◽  
Torsional Vibration ◽  
High Speed ◽  
Planetary Gear ◽  
Vibration Modes ◽  
Ring Gear ◽  
Natural Modes

A purely torsional dynamic model of closed-form planetary gear set is developed to investigate its natural frequency and free vibration modes. The closed-form planetary gear set considered consists of two-stage planetary gear connected by high-speed carrier and ring gear. Three identical planet gears are equally spaced in each stage. Based on the precondition, the natural modes are classified into three types of vibration modes: overall modes，high-speed planet mode and low-speed planet mode

Nonlinear Parametric Vibrations of an Elastic Structure With a Cylindrical Liquid Container (in the Case of an Anti-Symmetric Sloshing Mode)

2001 ◽  
Author(s):  
Takashi Ikeda ◽  
Shin Murakami
Keyword(s):  
Natural Frequency ◽  
Harmonic Balance ◽  
Small Deviation ◽  
Harmonic Balance Method ◽  
Mathieu Equation ◽  
Elastic Structure ◽  
Coupled Vibration ◽  
Sloshing Mode ◽  
Resonance Curves ◽  
Fft Analysis

Abstract The nonlinear-coupled vibrations of an elastic structure and liquid sloshing in a cylindrical container are investigated. Since the structure is vertically subjected to a sinusoidal excitation, the behavior of the liquid surface is governed by a kind of the Mathieu equation. Modal equations governing the coupled motions are derived, when the natural frequency of the structure is equal to twice the natural frequency of an anti-symmetric mode of sloshing. The theoretical resonance curves are also presented by using an FFT analysis and the improved harmonic balance method. The influences of a liquid level and a detuning parameter on the theoretical resonance curves are shown. A small deviation of the tuning condition can cause amplitude-modulated motions and separate the occurrence region of the coupled vibration into two regions. In the experiments, the theoretical resonance curves were qualitatively in agreement with the experimental data. In addition, amplitude-modulated motions were observed.

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