FE modeling of creep in linear and non-linear FGM cylinder under internal pressure

Abstract

Purpose -The purpose of this paper is to investigate creep in an internally pressurized thick-walled, closed ends cylinder made of functionally graded composite, having linear and non-linear distribution of reinforcement, using finite element (FE) analysis. Design/methodology/approach -FE-based Abaqus software is used to investigate creep behavior of a functionally graded cylinder. The cylinder is made of composite containing linear and non-linearly varying distributions of reinforcement along the radius. The creep behavior has been described by Norton's power law. The creep stresses and strains have been estimated in linear and non-linear functionally graded materials (FGM) cylinders and compared with those estimated for a similar composite cylinder but having uniform distribution of reinforcement. Findings -The radial stress in the composite cylinder is observed to decreases over the entire radius upon imposing linear or non-linear reinforcement gradients. However, the tangential stress in the cylinder increases near the inner radius but decreases toward the outer radius, on imposing linear or non-linear reinforcement gradients. The creep strains in the FGM cylinders are significantly lower than those observed in a uniform composite cylinder. Originality/value -The creep strains in an internally pressurized functionally graded thick composite cylinder could be reduced significantly by employing non-linear distribution of reinforcement along the radial direction.

Secondary Creep Analysis of FG Rotating Cylinder with Exponential, Linear and Quadratic Volume Reinforcement

“…The values of creep parameters [ 2 , 24 ] , and are taken as, , and , respectively. Here, for an isotropic cylinder, .…”

“…The values of creep parameters [2,24] B o , n o and n 3 are taken as, B o = 2.77 × 10 −6 , n o = 3.75 and n 3 = 0.7, respectively. Here, for an isotropic cylinder, F = G = H. The average volume content for SiC p is considered as V avg = 20%.…”

“…Rearchers have used various mathematical methods such as Runge Kutta 4th order, finite difference method (FDM), shooting method, complementary function method (CFM), homotopy analysis method for obtaining the solution of steady state creep in disks and cylinders made up of functionally graded materials. Creep models based on iterative technique, finite element method (FEM) and Seth’s transition theory for obtaining stress distribution in functionally graded rotating disks and cylinders can be also found in the literature [ 23 , 24 , 25 ]. Nie and Batra [ 26 ] studied the problem of material tailoring to obtain desired stress field in hollow cylinder made up of functionally graded in-compressible material with radially varying shear modulus.…”

Creep of autofrettaged thick-walled FGM cylindrical vessel

“…The values of B 0 , n 0 , u, according to Chen et al, 57 are 2:77 3 10 À16 , 3:75, 0:7, respectively. However, it has been shown that changing these parameters (B r ð Þ, n r ð Þ) has little effect on the strain rate in the Norton equation, 32,51 so in the present work these two parameters are considered constant (B = 4:79 3 10 À22 MPa À6 s À1 , n = 6). 51 By substituting equations (19) and (20) into equation (40), _ e r r i ð Þ and _ e u r i ð Þ are as follows:…”

“…The most common model for describing the change in the properties of FGM is the application of the power model based on the volume fraction of the material components. In this model, the change in material properties in terms of thickness based on the volume fraction is expressed as follows 51 :…”