scholarly journals Installation for Producing Mechanical Vibrations used in the Finishing of the Welded Joints Structure

2020 ◽  
Vol 22 (1) ◽  
pp. 79-84
Author(s):  
Bogdan Novac
Keyword(s):  
Magnetic Properties ◽  
Welded Joints ◽  
Mechanical Vibration ◽  
Vibration System ◽  
Mechanical Vibrations ◽  
Speed Measurement ◽  
Stress Relieving ◽  
Constructive Version ◽  
Vibration Wave ◽  
Speed Adjustment

Abstract The paper presents a constructive version of a mechanical vibration generator designed to be used at stress relieving of welded joints. This installation can be used on all brands of steels and welded joints, whether they have magnetic properties or not. In the generator construction a DC motor was used, in order to be able to adjust the speed more easily. The speed adjustment is made with a potentiometer, and the speed measurement is made with a tachometer. The tachometer measures the speeds based on the pulses given by a four-pointed cam rotating between the plates of a capacitor. The vibration system also contains a piezoelectric accelerograph, which is attached to the welded part subjected to vibration, in order to measure the level of vibration and the parameters of the vibration wave.

THE EFFECT OF MECHANICAL VIBRATION ON STRESS RELIEVING OF WELDED JOINTS

2019 ◽  
Author(s):  
DANILO CESAR DE AZEVEDO MONTEIRO ◽  
Tatiane de Campos Chuvas ◽  
Maria Cindra Fonseca
Keyword(s):  
Welded Joints ◽  
Mechanical Vibration ◽  
Stress Relieving

scholarly journals Influence of mechanical activation and heat treatment on magnetic properties of nanostructured mixture Ni85.8Fe10.6Cu2.2W1.4

2019 ◽  
Vol 55 (1) ◽  
pp. 85-93 ◽  
Author(s):  
M.M. Vasic ◽  
A.S. Kalezic-Glisovic ◽  
R. Milincic ◽  
Lj. Radovic ◽  
D.M. Minic ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Thermal Treatment ◽  
Mechanical Activation ◽  
Powder Mixture ◽  
Structural Characteristics ◽  
Volume Density ◽  
Magnetic Domains ◽  
Microstructural Changes ◽  
Mass Magnetization ◽  
Stress Relieving

The mechanical activation of the Ni85.8Fe10.6Cu2.2W1.4 powder mixture in the time intervals of 30-210 min in combination with thermal treatment at 393-873 K resulted in microstructural changes, forming the nanostructured mixture of the same composition but improved magnetic properties. The best result were achieved for mechanical activation during 120 min and thermal treatment at temperatures close to the Curie temperature (693K), enhancing the mass magnetization of the starting powder mixture by about 57%. The microstructural changes, which include the structural relaxation, decrease in free volume, density of dislocation and microstrain, improve structural characteristics of material, enabling better mobility of walls of magnetic domains and their better orientation in applied magnetic field and consequently enabling better mass magnetization of the material. With longer time of milling, the growing stress introduced in the sample undergoes easier relief, relocating stress-relieving processes toward lower temperatures.

scholarly journals Modal Analysis and Rotor-Dynamics of an Interior Permanent Magnet Synchronous Motor: An Experimental and Theoretical Study

2020 ◽  
Vol 10 (17) ◽  
pp. 5881
Author(s):  
Selma Čorović ◽  
Damijan Miljavec
Keyword(s):  
Modal Analysis ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Natural Frequencies ◽  
Permanent Magnet Synchronous Motor ◽  
Mechanical Vibration ◽  
Mechanical Vibrations ◽  
Wide Range ◽  
Interior Permanent Magnet ◽  
Interior Permanent Magnets

This paper investigates mechanical vibrations of an interior permanent magnet (IPM) synchronous electrical motor designed for a wide range of speeds by virtue of the modal and rotordynamic theory. Mechanical vibrations of the case study IPM motor components were detected and analyzed via numerical, analytical and experimental investigation. First, a finite element-based model of the stator assembly including windings was set up and validated with experimental and analytical results. Second, the influence of the presence of the motor housing on the natural frequencies of the stator and windings was investigated by virtue of numerical modal analysis. The experimental and numerical modal analyses were further carried out on the IPM rotor configuration. The results show that the natural frequencies of the IPM rotor increase due to the presence of the magnets. Finally, detailed numerical rotordynamic analysis was performed in order to investigate the most critical speeds of the IPM rotor with bearings. Based on the obtained results, the key parameters related to mechanical vibrations response phenomena, which are important when designing electrical motors with interior permanent magnets, are provided. The main findings reported here can be used for experimental and theoretical mechanical vibration analysis of other types of rotating electrical machines.

An Analysis of the Galvanometer Amplifier and its Response to Alternating Electromotive Forces and Mechanical Vibrations

1951 ◽  
Vol 4 (4) ◽  
pp. 560
Author(s):  
RG Wylie ◽  
AFA Harper
Keyword(s):  
Frequency Response ◽  
Response Curve ◽  
Mechanical Vibration ◽  
Frequency Response Curve ◽  
Mechanical Vibrations ◽  
Frequency Axis ◽  
Critical Damping

A system which is representative of most practical galvanometer amplifiers is analysed and the response of the system to alternating e.m.f.'s and to mechanical vibration is determined. It is shown that the values of the circuit constants can be so chosen that the galvanometer movement is at least critically damped for all conditions of operation and that, for critical damping. the frequency response curve for the amplifier to applied alternating e.m.f.'s resembles that for the galvanometer alone but is expanded along the frequency axis by a factor which depends on the degree of feedback. Mechanical vibration with a component about the axis of the galvanometer cod produces an effect which is markedly increased by the provision of feedback.

On establishing equations of motion of mechanical vibration systems placed on moving bases

2017 ◽  
Vol 45 (3) ◽  
pp. 209-227
Author(s):  
M Gürgöze ◽  
F Terzioğlu
Keyword(s):  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Mechanical Vibration ◽  
Main Idea ◽  
Vertical Axis ◽  
Constant Angular Velocity ◽  
Vibration System ◽  
Reaction Forces ◽  
The Subject ◽  
Vibrating Systems

The first author has been teaching the postgraduate course, “The Dynamics of Mechanical Systems” in The ITU Faculty of Mechanical Engineering for nearly 20 years. He has observed that students frequently have problems in obtaining the equations of motion of the vibrating systems which were placed on moving bases. Starting from this observation, he has found that the homework stated below, which was given to the students occasionally, was very helpful in learning the subject. The main idea of the homework is the derivation of the equations of motion, with the help of formulating the Lagrange’s equations with respect to a moving set of axis for a vibration system with two degrees of freedom which consists of a horizontal table rotating with a constant angular velocity around a vertical axis. The students were also asked to solve the same problem with a different method of their choice and to determine the reaction forces as well. We want to share this problem with the reader, which we have assessed as very instructive and appropriate from the viewpoint of applicability of different methods.

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