Natural frequencies

This paper applies the homotopy analysis method to study nonlinear free vibrations. The paper has used the homotopy analysis method to find analytical solutions of a nonlinear two-degree-of-freedom system. Analytical results have found the natural oscillation frequencies, the displacement formula of the system are approximately calculated at the 10th order.

9p viengfa 28-10-2024 2 0   Download

This paper presents the data processing method using Hilbert Huang Transform (HHT) algorithm in determining a time-dependent frequencies of steel frame. The vibration experiment for steel frame was conducted in this study.

10p viyoko 24-09-2024 2 1   Download

In this paper, the static and dynamic behaviour of sandwich beams with porous core are numerically analyzed and validated by experimental tests. The beam consists of a thick porous core with a uniform porosity distribution over its domain and two outer face layers.

16p vifaye 20-09-2024 1 1   Download

This article presents an improved procedure for detecting single damage in beam-like structures. Many damage detection methods are based on the analysis of beam natural frequency shifts in damaged and intact states and its analytical modal curvatures.

15p vifaye 20-09-2024 4 1   Download

A new semi-empirical technic has been established relying on the linkage between the chemistry in the bulk liquid and that taking place in the acoustic cavitation bubble. The open-source COPASI software has been used for the optimization of number density according to the total yield of a single bubble and the fitting of the experimental yield of hydrogen peroxide in the sonicated solution. It was observed that the number density is increased with the rise of ultrasound frequency from 200 to 1140 kHz, independently of the saturating gas nature (O2, Ar or air).

10p dianmotminh02 03-05-2024 4 3   Download

The dynamic analysis is a necessity in the design, manufacturing and maintenance of structures. The analytic solutions are not available for most practical cases and the Finite Element Method (FEM) is not reliable due to the joint problem, unclear loading, material properties and numerical error. In this paper, we present a way to find modes shape of 3D Frame by FEM program using Matlab.

8p vidoctorstrange 06-05-2023 7 3   Download

In this paper, the Finite Element Method (in ANSYS) is used to investigate natural frequency of vibration and bending characteristics under varying pressure loads applied on the top skin when changing fundamental properties of some gradient configurations, including angular gradient, thickness gradient and functional gradient configurations of the auxetic plate with honeycomb structure.

17p meyerowitz 25-12-2021 9 1   Download

Privacy-preserving frequency mining is a quite simple technique, but it is very useful in privacy-preserving machine learning and data mining. In this paper, we construct an elliptic curve analog of the ElGamal system-based protocol for privacy-preserving frequency mining in fully distributed setting.

8p tamynhan9 02-12-2020 16 2   Download

An experiment was conducted to study the effectiveness and efficiency of one physical mutagen i.e. gamma rays and two chemical mutagens i.e. ethyl methanesulfonate (EMS) and nitrosoguanidine (NG) in greengram. To study the nature and effect of mutagens in greengram, the percentage of lethality, pollen sterility, frequency of chlorophyll mutations, mutagenic effectiveness, mutagenic efficiency and mutation rates of each mutagen were estimated.

9p angicungduoc6 22-07-2020 16 3   Download

The results indicated that the majority of employees belong to the age group of 20-25years. The result also showed that about two-third of ITES employees belong to the monthly income group of Rs 10000- 15000 and the majority of ITES employees are single.

8p guineverehuynh 21-06-2020 11 4   Download

This paper presents a numerical analysis of free vibration of thin circular and annular plate using finite element method. The first five natural frequencies are presented for uniform annular plates of various inner-to-outer radius ratios, with nine possible combinations of free, clamped and simply supported boundary conditions at the inner and outer edges of plates.

8p tohitohi 19-05-2020 30 2   Download

In this paper, an analytical solution for whirling analysis of axial-loaded Timoshenko rotor is presented and corresponding basic functions are derived. The set of governing equations for whirling analysis of the rotor consists of four coupled partial differential equations; using complex displacements, these equations can be reduced to two coupled partial differential equations.

12p tohitohi 19-05-2020 14 0   Download

In this research, the influences of modal properties of a micro cubic satellite on equivalent static loads (due to combination of quasi-static and dynamic loads during launch time) have been studied. The study shows that the magnitude of equivalent static loads can be affected by satellite effective modes and effective mass distribution along natural frequencies.

10p tohitohi 19-05-2020 9 0   Download

In this paper, an analytical method is proposed for calculation of natural frequencies of a delaminated composite beam from both free and constrained mode frequencies. In previous studies, the frequencies of a delaminated composite beam were computed with assumption of occurring open or close delamination during the vibration.

8p tohitohi 19-05-2020 19 1   Download

The present paper addresses the problem for free vibration of multistep Timoshenko beams with arbitrary number of cracks, continuing the work accomplished in [28], where the problem was studied on the base of Euller-Bernoulli beam theory. First, the obtained general solution of uniform Timoshenko beam is employed to develop the TMM for modal analysis of multistep Timoshenko beam with multiple cracks. Then, effect of beam slenderness and stepped change in cross section on sensitivity of natural frequencies to cracks is thoroughly examined.

16p abcxyz123_02 03-03-2020 20 3   Download

The research objectives of the thesis are to study the nature of operational efficiency, criteria for identifying and measuring the performance of enterprises; survey the importance and frequency of using performance analysis criteria; complete a system of criteria for analyzing operational efficiency to meet the use needs of Vietnamese paper enterprises.

0p gaunguyen6789 17-09-2019 49 2   Download

The aim of this thesis is to study crack-induced change in natural frequencies and to develop a procedure for detecting cracks in stepped beams by measurement of natural frequencies.

27p xacxuoc4321 11-07-2019 32 3   Download

In this communication, we report the synthesis of chitosan (CS, a biodegradable and biocom- patible natural polymer) [1] nanoparticles as drug carriers by ionic gelation. The method is based on ionic interactions between positively charged groups NH3 + of CS (in dilute CH3COOH solution) and negatively charged of sodium tripolyphos- phate, TPP).

2p uocvong04 24-09-2015 85 4   Download

In both industrial fermenters and in their natural habitats, microorganisms often experience an inhomogeneous and fluctuating environment. In this paper we mimicked one aspect of this nonideal behaviour by imposing a low and oscillating extracellular glucose concentration on nonoscillating suspensions of yeast cells. The extracellular dynamics changed the intracel-lular dynamics – which was monitored through NADH fluorescence – from steady to equally dynamic; the latter followed the extracellular dynamics at the frequency of glucose pulsing....

9p awards 06-04-2013 46 4   Download

In this paper, we study the growth of sX(L), the number of simple closed geodesics of length ≤ L on a complete hyperbolic surface X of finite area. We also study the frequencies of different types of simple closed geodesics on X and their relationship with the Weil-Petersson volumes of moduli spaces of bordered Riemann surfaces.

30p dontetvui 17-01-2013 49 7   Download