Effect of Thermal Gradient on Vibration Characteristics of a Functionally Graded Shaft System

Abstract

The study aims to investigate the vibration characteristics of ceramic-based functionally graded materials (FGM) when subjected to dynamic conditions. Effect of thermal gradients on natural frequencies of rotating FG shafts has been investigated using three dimensional (3D) solid elements which is rarely found in literature. The FG material used in the work has metal and ceramic as its constituents. Three-dimensional finite element modelling and analysis of the FG shaft system has been carried out using ANSYS software to determine the natural frequencies with proper validations. The study involves modelling of the shaft using two different material laws; power-law and exponential law. Continuous variation of material properties is achieved using a Python code that discretizes the shaft radially and applies the position-dependent material properties. The shaft has been subjected to different thermal environments by applying temperature gradients accordingly. Thermal gradation is achieved using two different methods, nonlinear temperature distribution (NLTD) and exponential temperature distribution (ETD). Effects of material gradation on the fundamental frequencies of the shaft is presented. The variations due to different material laws and thermal gradients are also identified. The whirl frequencies have been determined for the rotating shaft system. The effect of material gradation laws and temperature gradients on separation of the frequencies at rotating speeds is determined. Attempts have been made to obtain suitable reasons for the behaviours based on the material properties. The obtained results show the influence of material gradation methods, power-law index, and temperature gradients on vibration characteristics of the ceramic-based FG shaft system. Furthermore, the reasons of the variations are also discussed in detail.

Effect of Corrosion on the Natural and Whirl Frequencies of a Functionally Graded Rotor-Bearing System Subjected to Thermal Gradients

“…Bose and Sathujoda [ 18 ] performed a natural frequency analysis of a functionally graded rotor system using a three-dimensional finite element model developed using ANSYS (ANSYS 18.0, ANSYS, Canonsburg, PA, USA). Furthermore, Bose and Sathujoda [ 19 ] extended this work and studied the effects of thermal gradients on the vibration characteristics of an FG rotor-bearing system.…”

Steady State and Transient Vibration Analysis of an Exponentially Graded Rotor Bearing System Having a Slant Crack

“…Mahi et al [15] investigated the free vibration frequencies of an FG beam for different material distributions (power-law, exponential-law and sigmoid-law) under a thermal environment based on a unified higher-order shear deformation theory. The effect of temperature gradients on fundamental frequencies of an FG rotor-bearing system based on the Timoshenko beam theory is investigated by Bose and Sathujoda [16].…”

A Study on Dynamic Behaviour of Thermally Distributed Exponentially Graded Rotor System with Induced Porosities

“…Obalareddy et al [22] investigated the free vibration behaviour of an FG rotor-bearing system subjected to temperature gradients by employing the dynamic stiffness matrix approach. e effect of thermal gradients on the vibrational behaviour of the FG rotor system was analysed by Bose and Sathujoda [23].…”