Creep Analysis in Anisotropic Composite Rotating Disc with Hyperbolically Varying Thickness

2011 ◽  
Vol 110-116 ◽  
pp. 4171-4177
Author(s):  
Vandana Gupta ◽  
S.B. Singh
Keyword(s):  
Creep Behavior ◽  
Yield Criterion ◽  
Radial Strain ◽  
Outer Radius ◽  
Rotating Disc ◽  
Tangential Strain ◽  
Varying Thickness ◽  
Creep Analysis ◽  
Inner Radius ◽  
Hill's Yield Criterion

Steady state creep in a anisotropic rotating disc made of Al-SiCp composite having hyperbolically varying thickness has been investigated using Hill’s yield criterion. The creep behavior is supposed to follow the Sherby’s law in present study. The stress and strain distributions are calculated for different combinations of anisotropic constants. The change in the radial stress is not significant while the tangential stress is changed with the change in the material constants. The tangential strain rates are highest at the inner radius of the disc and then decreases towards the outer radius of the disc. The radial strain rate which is compressive in nature becomes tensile in middle of the disc for some specific values of anisotropic constants. The study reveals that the anisotropy has a significant effect on the creep behavior of rotating disc. Thus for the safe design of the rotating disc the effect of anisotropy should be taken care of.

EFFECT OF RESIDUAL STRESS AND REINFORCEMENT GEOMETRY IN AN ANISOTROPIC COMPOSITE ROTATING DISC HAVING VARYING THICKNESS

2012 ◽  
Vol 01 (04) ◽  
pp. 1250035
Author(s):  
VANDANA GUPTA ◽  
S. B. SINGH
Keyword(s):  
Residual Stress ◽  
Steady State ◽  
Creep Behavior ◽  
Yield Criterion ◽  
Steady State Creep ◽  
Thermal Residual Stress ◽  
Rotating Disc ◽  
Varying Thickness ◽  
Creep Analysis ◽  
Sic Particle

The influence of the thermal residual stress and reinforcement geometry on the creep behavior of a composite disc has been analyzed in this paper. The creep analysis in a rotating disc made of Al-SiC (particle/whisker) composite having hyperbolically varying thickness has been carried out using anisotropic Hoffman yield criterion and results obtained are compared with those using Hill's criterion ignoring difference in yield stresses. The steady state creep behavior has been described by Sherby's creep law. The creep parameters characterizing difference in yield stresses have been used from the available experimental results in literature. It is observed that the stresses are not much affected by the presence of thermal residual stress, while thermal residual stress introduces significant change in the strain rates in an anisotropic rotating disc. Secondly, it is noticed that the steady state creep rates in whisker reinforced disc with/without residual stress are observed to be significantly lower than those observed in particle reinforced disc with/without residual stress. It is concluded that the presence of residual stress in an anisotropic disc with varying thickness needs attention for designing a disc.

scholarly journals Creep Modeling in a Composite Rotating Disc with Thickness Variation in Presence of Residual Stress

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Vandana Gupta ◽  
S. B. Singh
Keyword(s):  
Residual Stress ◽  
Steady State ◽  
Creep Behavior ◽  
Yield Criterion ◽  
Steady State Creep ◽  
Thickness Variation ◽  
Stress And Strain ◽  
Rotating Disc ◽  
Varying Thickness ◽  
Von Mises

Steady-state creep response in a rotating disc made of Al-SiC (particle) composite having linearly varying thickness has been carried out using isotropic/anisotropic Hoffman yield criterion and results are compared with those using von Mises yield criterion/Hill's criterion ignoring difference in yield stresses. The steady-state creep behavior has been described by Sherby's creep law. The material parameters characterizing difference in yield stresses have been used from the available experimental results in literature. Stress and strain rate distributions developed due to rotation have been calculated. It is concluded that the stress and strain distributions got affected from the thermal residual stress in an isotropic/anisotropic rotating disc, although the effect of residual stress on creep behavior in an anisotropic rotating disc is observed to be lower than those observed in an isotropic disc. Thus, the presence of residual stress in composite rotating disc with varying thickness needs attention for designing a disc.

Modeling Creep Analysis of Thermally Graded Anisotropic Rotating Composite Disc

2018 ◽  
Vol 10 (06) ◽  
pp. 1850063 ◽  
Author(s):  
Tania Bose ◽  
Minto Rattan
Keyword(s):  
Temperature Field ◽  
Elevated Temperatures ◽  
Yield Criterion ◽  
Particulate Composite ◽  
Rotating Disc ◽  
Modeling And Analysis ◽  
Creep Analysis ◽  
Modeling Creep ◽  
Hill's Yield Criterion ◽  
Silicon Carbide Particulate

Mathematical modeling for steady-state creep has been done for an anisotropic disc of aluminium-silicon carbide particulate composite rotating at elevated temperatures under a thermal gradient. Creep modeling and analysis has been done using Hill’s yield criterion for a disc operating under a parabolic distributed temperature and its comparison is made with the disc operating under uniform temperature throughout the radius. The results are expressed graphically in designer friendly manner for the stress and strain rate distributions under a graded temperature field. It can be seen that the parabolic temperature field has a significant effect on the creep behavior of the anisotropic disc. Thus, the temperature gradient effect should be considered while designing the anisotropic rotating disc.

scholarly journals Elastoplastic Analysis of Circular Tunnel Based on Drucker–Prager Criterion

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Xiongfei Yang ◽  
Hong Yuan ◽  
Jiayu Wu ◽  
Shanqing Li
Keyword(s):  
Internal Friction ◽  
Yield Criterion ◽  
Radial Strain ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Circular Tunnel ◽  
Piecewise Linearization ◽  
Tangential Strain ◽  
Tunnel Excavation ◽  
Excavation Process

Based on the Drucker–Prager yield criterion, the theoretical solution of stratigraphic deformation in tunnel excavation process is deduced by the cavity expansion theory. In view of soil loosening around the tunnel caused by the tunnel excavation process, the internal friction angle of the surrounding soil is not a constant but a function of normal stress. The piecewise linearization of the nonlinear yield function is used to analyze the elastoplastic solution of the cylindrical hole shrinkage. A comparison is conducted with a plastic zone in which the internal friction angle of the soil remains unchanged. It can be concluded that the radial stress, the tangential stress, the radial strain, and the tangential strain around the inner wall calculated from the former are smaller.

Effect of anisotropy on creep behavior in a functionally graded material disc of variable thickness

2014 ◽  
Vol 03 (03) ◽  
pp. 1450017 ◽  
Author(s):  
Vandana Gupta ◽  
S. B. Singh
Keyword(s):  
Steady State ◽  
Creep Behavior ◽  
Functionally Graded Material ◽  
Radial Distance ◽  
Outer Radius ◽  
Functionally Graded ◽  
Steady State Creep ◽  
Rotating Disc ◽  
Creep Response ◽  
Graded Material

In this paper, an effort has been made to study the effect of anisotropy on the steady state creep behavior in the functionally graded material disc with hyperbolic thickness made of Al - SiC (particle). The content of silicon carbide particles in the disc is assumed to decrease linearly from the inner to the outer radius of the disc. The creep behavior of the disc under stresses developing due to rotation at 15,000 rpm has been determined by Sherby's law. The creep parameters of the FGM disc vary along the radial distance due to varying composition and this variation has been estimated by regression fit of the available experimental data. The creep response of rotating disc is expressed by a threshold stress with value of stress exponent as 8. The study reveals that the anisotropy has a significant effect on the steady state creep response of rotating FGM disc. Thus, the care to introduce anisotropy should be taken for the safe design of the rotating FGM disc with hyperbolic thickness.

Influence of anisotropy on creep in functionally graded variable thickness rotating disc

2021 ◽  
pp. 030932472199997
Author(s):  
Kishore Khanna ◽  
Vinay Kumar Gupta ◽  
Neeraj Grover
Keyword(s):  
Axial Direction ◽  
Functionally Graded ◽  
Strain Rates ◽  
Lower Yield ◽  
Rotating Disc ◽  
Creep Response ◽  
Varying Thickness ◽  
Disc Material ◽  
Lower Yield Strength ◽  
Tangential Directions

The study is carried out to develop a mathematical model to analyze creep response of a varying thickness rotating disc made of anisotropic functionally graded 6061Al-SiCw.composite. The thickness and content of reinforcement (SiCw) in the disc are assumed to decrease radially according to power law. The yielding of disc material is according to Hill’s criterion and creeping as per threshold stress based law. The developed model is used to obtain the creep stresses and strain rates in the disc for various types of materials’ anisotropy. The stresses and strain rates are noticed to depend on the materials’ anisotropy. The study reveals that the presence of kind of anisotropy wherein the disc material exhibits lower yield strength toward the radial and tangential directions than the axial direction is beneficial in reducing the creep stresses and creep rates in the disc, in comparison to isotropic FGM disc. An anisotropic FG disc, which has highest and the lowest yield strengths, respectively, along the axial and radial directions shows superior creep response.

Improved Diffuser/Volute Combinations for Centrifugal Compressors

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
T. Steglich ◽  
J. Kitzinger ◽  
J. R. Seume ◽  
R. A. Van den Braembussche ◽  
J. Prinsier
Keyword(s):  
Cross Sections ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Outer Radius ◽  
Inner Radius ◽  
Pressure Pipeline ◽  
The Cross ◽  
Improved Performance ◽  
High Pressure Pipeline ◽  
Original Configuration

Internal volutes have a constant outer radius, slightly larger than the diffuser exit radius, and the circumferential increase of the cross section is accommodated by a decrease of the inner radius. They allow the design of compact radial compressors and hence are very attractive for turbochargers and high-pressure pipeline compressors, where small housing diameters have a favorable impact on weight and cost. Internal volutes, however, have higher losses and lower pressure rise than external ones, in which the center of the cross sections is located at a larger radius than the diffuser exit. This paper focuses on the improvement of the internal volute performance by taking into account the interaction between the diffuser and the volute. Two alternative configurations with enhanced aerodynamic performance are presented. The first one features a novel, nonaxisymmetric diffuser̸internal volute combination. It demonstrates an increased pressure ratio and lower loss over most of the operating range at all rotational speeds compared with a symmetric diffuser̸internal volute combination. The circumferential pressure distortion at off design operation is slightly larger than in the original configuration with a concentric vaneless diffuser. Alternatively, a parallel-walled diffuser with low-solidity vanes and an internal volute allows a reduction of the unsteady load on the impeller and an improved performance, approaching that of a vaneless concentric diffuser with a large external volute.

Creep Analysis for an Unbonded Flexible Pipe Barrier

2006 ◽  
Author(s):  
Lun Qiu ◽  
John Zhang
Keyword(s):  
Finite Element ◽  
Creep Behavior ◽  
Barrier Layer ◽  
Polyvinylidene Fluoride ◽  
Element Model ◽  
Polymer Materials ◽  
Flexible Pipe ◽  
Internal Fluid ◽  
Creep Analysis ◽  
Parameter Matching

The fluid barrier in an unbonded flexible pipe seals the pressure from the internal fluid. Since the barrier is usually made of polymer materials, it is unable to hold the pressure by itself. A metal reinforced hoop layer is usually needed outside the barrier layer in order to resist the pressure. The hoop layer is usually a steel bar with a cross-section of an irregular shape. It is helically wrapped at the outside of the barrier layer. When the pipe is pressurized, the barrier will be supported by the hoop reinforcement layer from outside. However, at the gap between the steel wraps where the barrier layer bridges, material of the barrier will be forced to extrude into the gap. The amount of the extrusion is a function of many parameters such as temperature, material property, and internal pressure and so on. In addition, it is time dependent. The creep effect needs be considered. It is critical to have a proper barrier design for a flexible pipe structure. This article presents a practical finite element method for evaluation of the barrier/gap design. The creep behavior of the polymers is multi-parameter related. Therefore, a series of material tests has been conducted under various stresses and temperatures for nylon, polyethylene and Polyvinylidene Fluoride. In this work a method is given to determine the creep behavior parameters through parameter matching based on the tests. The creep deformation of barrier was analyzed with a finite element model using these parameters.

On the Vibration of a Rotating Disk

1972 ◽  
Vol 39 (4) ◽  
pp. 1143-1144 ◽  
Author(s):  
S. Barasch ◽  
Y. Chen
Keyword(s):  
Approximate Calculation ◽  
Initial Conditions ◽  
Rotating Disk ◽  
Equation Of Motion ◽  
Outer Radius ◽  
Order Equation ◽  
System Of Differential Equations ◽  
Fourth Order Equation ◽  
First Order ◽  
Inner Radius

The equation of motion of a rotating disk, clamped at the inner radius and free at the outer radius, is solved by reducing the fourth-order equation of motion to a set of four first-order equations subject to arbitrary initial conditions. A modified Adams’ method is used to numerically integrate the system of differential equations. Results show that Lamb-Southwell’s approximate calculation of the frequency is justified.

scholarly journals Elasto - plastic analysis of anisotropic hardening materials by finite element method

1985 ◽  
Vol 7 (1) ◽  
pp. 8-13
Author(s):  
Tran Duong Hien
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Program ◽  
Yield Criterion ◽  
Element Model ◽  
Isotropic Hardening ◽  
Anisotropic Hardening ◽  
Numerical Examples ◽  
Plastic Analysis ◽  
Hill's Yield Criterion

An elasto- plastic analysis for general three dimes10nal problems using a finite element model is presented. The analysis is based on Hill's yield criterion which included anisotropic materials displaying kinematic - isotropic hardening. The validity and practical applicability of the algorithm are illustrated by a number of numerical examples, calculated by a computer program written in fortran.

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