Effect of the Cross-Sectional Shape on the Dynamic Response of a Cantilever Steel Beam Using Three Modal Analysis Methods

Mar 12, 2024

Journal Mathematical Modelling of Engineering Problems

DOI https://doi.org/10.18280/mmep.110310

The main method for determining the vibration characteristics of engineering constructions is modal analysis. It's a way of analyzing a system's mode shapes, natural frequencies, and damping factor. The dynamic response of cantilever beams is determined in this work with different cross-sectional shapes to find the effect of eccentricity on the dynamic response of the cantilever beam. The main goal of this research is to find and detect the natural frequencies and mode shapes of a Structural Steel cantilever beam with different eccentricities and to identify flexural or torsional natural frequencies, as well as their mode shapes that could be confused with transverse natural frequencies, and to compare the results with analytical and experimental methodologies. Results showed that torsional natural frequencies remained within the transverse natural frequency. It can be shown that, the increase of eccentricity in the cross section decreases the natural frequencies and especially the torsional natural frequencies. The results were compared experimentally and numerically using ANSYS 16.1 software. There is a strong link between the mathematical, FEA, and experimental results. The latest results can be used to calculate failure loads in a variety of situations. The mathematical application of Euler's Bernoulli's beam concept was applied. The results of the three ways have been declared satisfactory.

Effect of Taper Forms on the Dynamic Response of A Rectangular Cross Section Cantilever Beam

Sep 2, 2023

Journal Al-Rafidain Engineering Journal

Tapered beams are more effective than uniform beams because they offer a superior distribution of mass and strength and also satisfy unique functional requirements in many engineering applications. This study calculates the mode shapes and natural frequencies of straight and various tapered Euler-Bernoulli beams by finite elements using ANSYS 16.5 software. The dynamic response for a cantilever beam was obtained for different taper angles. The results were compared with the dynamic response of a straight cantilever beam, to show the effect of the taper ratio on the dynamic response of the cantilever beam, when its volume and mass are constant. The results showed that the natural frequencies were increased as the taper angle increases, and the torsional natural frequencies were shifted from the fourth natural frequency to the fifth one as the taper angle increases

Structure, Characteristics and Corrosion Behaviour of Gold Nanocoating Thin Film for Biomedical Applications

Nov 3, 2022

Nanocoatings thin films are layers deposited to improve required properties and corrosion resistance as a major objective for materials that are used for various biomedical applications such as biosensors. In this study, Gold (Au) thin films with 50 nm and 100 nm have been synthesized on Ni-Cr-Mo alloys by magnetron sputtering deposition technique. X-Ray diffraction (XRD), Atomic Force Microscopy (AFM), and Energy-dispersive X-Ray spectroscopy /Scanning Electron Microscopy (EDS/SEM ) have been used to distinguish the surfaces morphology. The results showed that there is no defects or micro-cracks with a uniform and homogenous film. It has spherical nanoparticles diameter morphology with 200-400 nm shaped to fine aggregation. The roughness average (Ra) decreased from 3.91 nm for 50 nm films to 3.70 nm for 100nm films with FCC crystal structure (111) for gold thin films. In vivo, after 50 nm and 100 nm nanocoated thin film by gold, a significant improvement in the localized corrosion resistance has been obtained in artificial saliva corrosive media at 37 °C compared with the uncoated surface.

Structure and characteristics of Nb2O5 nanocoating thin film for biomedical applications

May 23, 2022

Journal Materials Today: Proceedings

The Effect of Multi-Walled Carbon Nanotubes Additives on the Tribological Properties of Austempered AISI 4340 Steel

Mar 6, 2022

Journal Journal Européen des Systèmes Automatisés

DOI https://doi.org/10.18280/jesa.550311

Due to a combination of optimal properties such as great strength, high hardness, good process ability, and good mechanical properties, AISI 4340 steel is widely used in many critical industrial applications such as nuclear, military, defense, and aerospace. It is also widely used in hydraulic forged machine tools, forged automotive crankshaft systems, shafts and gears, because of their improved characteristics, and its good tribological properties. The purpose regarding this work is to check the tribological characteristics of austempered AISI 4340 steel while dry and lubricated with machinery oil of SAE 30 grade as base oil. As received, AISI 4340 steel samples have been austempered to four definitely austenitic phase temperatures (850℃, 900℃, 1000℃, and 1050℃) for 90 minutes before being immersed in a mixture of potassium nitrite and sodium nitrite at 400℃ for 45 minutes. Friction and wear tests were then performed on austempered samples. Multiwalled carbon nanotube particles were blended at weight concentrations of 0.055, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, and 0.45 with typical machinery oil of 30 grade as base lubricant oil. A pin on the disc wear configuration was used in the experimental investigation. The use of Multi-Walled Carbon Nanotube (MWCNTs) additives in the base oil resulted in a decrease in both friction coefficients and wear rates values when compared to typical base oil lubricant. The results also showed a reduction in both friction coefficients and wear rates as the sample's austempering temperatures were raised. Sliding surfaces were also photo micro graphed, and when the volume concentrations of Multi- Walled Carbon Nanotube particles in the normal base oil lubricant were increased, smoother surfaces with less damage were shown.

A comparison study between base and forced excitation at the top floor for multi-story structure

Mar 22, 2020

Journal Conference Paper in AIP Conference Proceedings · March 2020

Abstract. Multistory buildings may subjected to many types of vibration excitation which affect their structures and properties. The period of vibration or natural frequency is an important parameter in building design as it governs the effect of wind or earthquake. A four story model has been constructed which simulates a multi-story shear structure (like a building). This model is connected to a shaker and a system of accelerometers to measure the dynamic response of that model and to make a comparison for two types of vibration excitations: base excitation and forced excitation at the top floor in order to investigate the dynamic response for the two cases. The results for the base excitation showed that the fundamental natural frequency was less than that for forced excitation at the top floor, and new natural frequencies have appeared in the spectrum. The level of vibration for the natural frequencies is higher compared to forced excitation. The overall level of vibration is higher too, and looks like the system became a selfexcitation. The mode shapes for the two cases were determined also, and compared to show that the more critical case is the base excitation.

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The effect of circular holes on the natural frequencies of a beam using transverse vibration measurements method

Jun 13, 2012

Journal Al-Rafidain Engineering

Defects influence in a negative way the service life of the structures. Thus, defect detection has been a considerable effort in order to eliminate this effect . In this study, the dynamical behavior of a cantilever beam, with different size of a hole, at different distances from the fixed end-for each case- have been measured, evaluated and compared with that of intact beam. It has been shown that the hole may be considered as a defect in most cases, which leads-in general- to decrease the stiffness, according to its size and place, hence affects the dynamic properties i.e., the natural frequencies and the mode shapes. A simulation process for the modal analysis using ANSYS program(release 12.1) is done in order to compare the results. In addition to that, a theoretical analysis is also done. The experimental results of the intact beam were compared with both the ANSYS program and the theoretical results. They showed an acceptable agreement between the three methods.

Tilt Angle Optimization of Solar Collectors for Maximum Radiation in Three Iraqi cities

Apr 12, 2012

Journal International Journal of Engineering and Industries(IJEI)

In this paper, optimal tilt angles were quantified for solar collectors based on the measured value of monthly average daily solar radiations on a horizontal surface in three Iraqi cities (Kirkuk, Baghdad, and Nasiriyah). The amount of radiation flux incident upon a solar collector is mainly affected by the installation angle. The dataset of monthly average daily global solar radiation on horizontal surfaces was measured for the three places mentioned above, while its components (direct and diffuse) were estimated using empirical model mentioned in this paper. The solar collector can be oriented at three different situations. The first setting, to adjust the collector at each month of the year to give maximum incident solar radiation (meeting optimum collector tilt angle). The second setting, suggests the seasonal changes (from winter, spring, summer, to autumn) using the average value of each three months to give one season. The final adjustment for solar collectors can be achieved using the average of the four seasons to get a yearly average throughout the year.

Corrosion Protection of Heat Treated Carbon Steel Surfaces By Passivity in the Industrial Atmospheres

Oct 7, 2010

Journal مجلة الهندسة والتكنولوجيا،

Abstract The object of this research is to study the passivity of surfaces of heat treated medium carbon steel (CK45) by annealing, spheroidise annealing, normalising, and water hardening. This research also studies corrosion resistance of corrosion protected samples by passivity in the industrial atmospheres for two periods (720 hr. and 1440 hr.). The results, which have been obtained, show that the corrosion rates in the unprotected samples are high compared with the corrosion protected samples by passivity.

Study of The Effect of Carbon Contents on The Corrosion Rate of Carbon Steels

Oct 1, 2009

Journal مجلة الھندسة والتكنولوجیا،

Issue 4

Volume 28

The Plain-Carbon steel are considered as one of the most common metallic materials used in engineering and industrial applications due to its ability in altering the micro-structures and mechanical properties as the result of carbon content. These alterations have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. The effect of carbon content on the corrosion resistance of Hypo-eutectoid plain carbon steels having different carbon contents such as 0.05%C , 0.2%C , 0.35%C , 0.5%C , and 0.65%C have been studied using three testing durations which are 4 weeks, 6 weeks, and 8 weeks and different corrosion environments such as atmosphere, fresh water, and salt water. The aim of the present work is to obtain the effect of carbon content on the corrosion resistance of steels in different corrosion medium by using the weight loss technique as a function of the corrosion resistance. The results, which have been obtained during this work show that a correlation can be made between corrosion rates and steels carbon content, and the corrosion resistance decreases with the increase in carbon content.