scholarly journals Dynamical simulation of a CNC turning centre

2020 ◽  
Vol 10 (2) ◽  
pp. 91-96
Author(s):  
Al-Zgoul Mohammad ◽  
Attila Szilágyi
Keyword(s):  
Natural Frequencies ◽  
Fem Analysis ◽  
Spindle System ◽  
Cnc Turning ◽  
Dynamical Simulation ◽  
Influence Coefficients ◽  
Cnc Turning Centre ◽  
The Way

This paper deals with the analysis of a CNC turning centre, more specifically the spindle system. The FEM analysis shows the natural frequencies of the spindle system and the same system was analysed by using the TMM and the influence coefficients method. These analyses pave the way to compare these three methods.

scholarly journals Dynamical Simulation of A CNC Turning Centre (Survey Paper)

2020 ◽  
Vol 10 (2) ◽  
pp. 85-90
Author(s):  
Al-Zgoul Mohammad ◽  
Attila Szilágyi
Keyword(s):  
Transfer Matrix Method ◽  
Degree Of Freedom ◽  
Cnc Turning ◽  
Rotor Systems ◽  
Survey Paper ◽  
Single Degree ◽  
Dynamical Simulation ◽  
Infinite Degree ◽  
Turning Center ◽  
Cnc Turning Centre

This paper shows the most common rotor systems which can be used to analyse a CNC turning center. Starting with the simplest rotor system representation (single-degree-offreedom) up to analysing multi-degree-of-freedom and infinite-degree-of-freedom rotor systems using the TMM (Transfer Matrix Method) when it comes to cases like multi desk rotors and Jeffcott-rotors.

Analysis of Mistuned Blade Vibrations Based on Normally Distributed Blade Individual Natural Frequencies

2015 ◽  
Author(s):  
Felix Figaschewsky ◽  
Arnold Kühhorn
Keyword(s):  
Probability Distribution ◽  
Development Process ◽  
Structural Model ◽  
Natural Frequencies ◽  
Rotor Blades ◽  
Lumped Mass ◽  
Mass Model ◽  
Influence Coefficients ◽  
Random Mistuning ◽  
Rotor Assembly

With increasing demands for reliability of modern turbomachinery blades the quantification of uncertainty and its impact on the designed product has become an important part of the development process. This paper aims to contribute to an improved approximation of expected vibration amplitudes of a mistuned rotor assembly under certain assumptions on the probability distribution of the blade’s natural frequencies. A previously widely used lumped mass model is employed to represent the vibrational behavior of a cyclic symmetric structure. Aerodynamic coupling of the blades is considered based on the concept of influence coefficients leading to individual damping of the traveling wave modes. The natural frequencies of individual rotor blades are assumed to be normal distributed and the required variance could be estimated due to experiences with the applied manufacturing process. Under these conditions it is possible to derive the probability distribution of the off-diagonal terms in the mistuned equations of motions, that are responsible for the coupling of different circumferential modes. Knowing these distributions recent limits on the maximum attainable mistuned vibration amplitude are improved. The improvement is achieved due to the fact, that the maximum amplification depends on the mistuning strength. This improved limit can be used in the development process, as it could partly replace probabilistic studies with surrogate models of reduced order. The obtained results are verified with numerical simulations of the underlying structural model with random mistuning patterns based on a normal distribution of individual blade frequencies.

Experimental analysis of power consumption in CNC turning centre for various chuck diameters

2021 ◽  
Author(s):  
N. Viswanathan ◽  
B. Pitchia Krishnan ◽  
V. Vimala ◽  
B. Balaji ◽  
U. Praveenkumar ◽  
...  
Keyword(s):  
Power Consumption ◽  
Experimental Analysis ◽  
Cnc Turning ◽  
Cnc Turning Centre

scholarly journals Vibrational Analysis on Hemp and Okra Fibres Mixed Glass Fiber Polyester Composite

2021 ◽  
Vol 8 (11) ◽  
pp. 55-62
Author(s):  
Putti Venkata Siva Teja ◽  
Badatala Ooha ◽  
Kondeti Sravanth
Keyword(s):  
Glass Fiber ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Fiber Composite ◽  
Fem Analysis ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Machine Component ◽  
Free System ◽  
Glass Fiber Composite

In transverse vibrations the element moves to and fro in a direction perpendicular to the direction of the advance of the wave. To determine the vibration characteristics i.e., natural frequencies and mode shapes, modal analysis is a process for a structure or a machine component while is being designed. In real life, aero planes, missiles, rockets, space vehicles, satellites, sub marines etc are modeled as free-free mechanical systems. In this paper an attempt was made to compare natural frequency for two composite materials- ladies finger with Glass fiber composite and Hemp with Glass fiber composite by taking as cantilever beams. The cantilever beam which is fixed at one end is vibrated to obtain the natural frequency, mode shapes at four different modes. A simple low cost demonstration experiment is performed in this paper by using common apparatus in order to compare theoretical, numerical (FEM analysis) profiles of two free-free thin two rectangular composite beams of dimensions 305*49.5* 7 in mm. Keywords: Natural frequencies, Mode shapes, Vibration characteristics, Ladies finger fiber, Hemp fiber, Glass fiber, FEM analysis, Free-Free system.

Experiment and FEM Analysis for Fracture of Fan Blades

2010 ◽  
Vol 143-144 ◽  
pp. 819-823
Author(s):  
Hai Ming Huang ◽  
Wen Jiao
Keyword(s):  
Natural Frequencies ◽  
Testing Machine ◽  
Fem Analysis ◽  
Hydraulic Testing ◽  
National Standard ◽  
The Finite Element Method ◽  
Nonlinear Fem ◽  
Rotating Speed ◽  
Mechanics Performance ◽  
Subway System

The fracture mechanism of fan blades in the subway system is analyzed by using the finite element method (FEM) and some experiments. Firstly, the mechanics performances of blade materials are obtained on the basis of the hydraulic testing machine. Then, the fracture surface of blades is measured with a scanning electron microscope (SEM). In the end, the natural frequencies of rotation blades are estimated by the means of nonlinear FEM program. It is shown from both the experiment and simulation results that the mechanics performance of blade materials is lower than its national standard, which is due to much bigger gaps and some inclusions in the cast fan. When voltage rises, the 79th natural frequency of blades becomes too approaching the rotating speed of fans easily to resonate. The biggest stress location of fan blades caused by centrifugal force, wind load and resonance is consistent in the fracture place, so the design of fan blades should be improved and optimized for preventing fracture.

Free Vibration and Stability of a Spinning Disk-Spindle System

1999 ◽  
Vol 121 (3) ◽  
pp. 391-396 ◽  
Author(s):  
R. G. Parker ◽  
P. J. Sathe
Keyword(s):  
Free Vibration ◽  
Strain Energy ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Modal Strain Energy ◽  
Spindle System ◽  
Disk Rotation ◽  
High Speeds ◽  
Elastic Disk ◽  
Strain Energy Ratio

This work examines the free vibration and stability of a spinning, elastic disk-spindle system. The extended operator formulation is exploited to discretize the system using Galerkin’s method (Parker, 1999). The coupled vibration modes of the system consist of disk modes, in which the disk dominates the system deformation, and spindle modes, in which the spindle dominates the system deformation. Both the natural frequencies and vibration modes are strongly affected by disk flexibility. If the membrane stresses associated with disk rotation are neglected then the system exhibits flutter instabilities, but these instabilities are not present when membrane stresses are modeled. Natural frequency veering between disk and spindle frequencies is prominent at low speeds and substantially affects the spectrum and stability. No veering is observed at high speeds where rotational stress stiffening diminishes disk-spindle coupling and causes the natural frequencies to converge to those of a rotating spindle carrying a rigid disk. Changes to the vibration modes are examined in terms of a strain energy ratio measuring the contribution of the disk strain energy to the total modal strain energy.

scholarly journals Application of optimization to change eigenfrequency of a pinion

Mechanik ◽  
2017 ◽  
Vol 90 (7) ◽  
pp. 588-590
Author(s):  
Jacek Stadnicki ◽  
Michał Głąbek
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Final Stage ◽  
Parametric Optimization ◽  
Natural Frequencies ◽  
Element Model ◽  
The Way

During the final stage of designing a pinion which is exploited at different rotational speeds, it is occasionally necessary to offset natural frequencies from frequencies of excitations. The way of solving this problem by means of parametric optimization of the pinion profile, assuming small changes of its shape, is discussed in the paper. The problem is solved using finite element model with regard to monolithic pinion of an aircraft gear.

Modal and Structural FEM Analysis of a 50 ft Pleasure Yacht

2012 ◽  
Vol 215-216 ◽  
pp. 692-697 ◽  
Author(s):  
Andrea Alaimo ◽  
Alberto Milazzo ◽  
Davide Tumino
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Fibre Composite ◽  
Fem Analysis ◽  
Element Analysis ◽  
Critical Areas ◽  
Design Loads ◽  
Glass Fibre Composite ◽  
Composite Skins

In this paper a structural Finite Element analysis of a 50 ft pleasure vessel is presented. The study is performed under different loads conditions: modal analyses have been done in order to find the natural frequencies of the vessel, structural analyses to verify the strength of the vessel to design loads. The design loads for the vessel considered are computed according to RINA rules for the construction and classification of pleasure vessels [1]. Two different composites are used for the lamination: one is a monolithic sequence of short fibre and balanced glass lamina, used for the bottom of the vessel and for structural reinforcements, the other is a sandwich made of glass fibre composite skins and a PVC core, used for the main deck and sides of the vessel. All the analyses are performed by using Patran/Nastran™ finite element commercial software in order to identify critical areas where possible reinforcement or redesign needs to be considered.

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